Inorganic Syntheses, Volume 36 E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Serie: Inorganic Syntheses
• Sprache: Englisch

Seitenzahl: 659

Veröffentlichungsjahr: 2014

Beschreibung

This volume of Inorganic Syntheses spans the preparations of wide range of important inorganic, organometallic and solid-state compounds. The volume is divided into 6 chapters. The first chapter contains the syntheses of some key early transition metal halide clusters and the very useful mononuclear molybdenum(III) synthon, MoCl3(THF)3. Chapter 2 covers the synthesis of a number of cyclopentadienyl compounds, including a novel route to sodium and potassium cyclopentadienide, MC5H5. Chapter 3 details synthetic procedures for a range of metal-metal bonded compounds, including several with metal-metal multiple bonds. Chapter 4 contains procedures for a range of early and late transition metal compounds, each a useful synthon for further synthetic elaboration. Chapter 5 deals with the synthesis of a number of main group compounds and ligands, while Chapter 6 covers teaching laboratory experiments.

Leseprobe

CONTENTS

Cover

Board of Directors

Title Page

Copyright

Preface

Dedication

Notice to Contributors and Checkers

Toxic Substances and Laboratory Hazards

Chapter One: Transition Metal Halide Compounds

1. Octahedral Hexatantalum Halide Clusters

A. Tetradecachlorohexatantalum Octahydrate

B. Tetradecabromohexatantalum Octahydrate

C. Tetrakis(Benzyltributylammonium) Octadecachlorohexatantalate

References

2. Octahedral Hexamolybdenum Halide Clusters

A. Tetradecachlorohexamolybdate Hexahydrate (Chloromolybdic Acid)

B. Hexamolybdenum Dodecachloride

References

3. Ether Complexes of Molybdenum(III) and Molybdenum(IV) Chlorides

A. Tetrachlorobis(Diethyl Ether)Molybdenum(IV)

B. Trichlorotris(Tetrahydrofuran)Molybdenum(III)

References

4. Octahedral Hexatungsten Halide Clusters

A. Bis(Hydroxonium) Tetradecachlorohexatungstate Heptahydrate (Chlorotungstic Acid)

B. Hexatungsten Dodecachloride

References

5. Trinuclear Tungsten Halide Clusters

A. Tritungsten Decachloride

B. Trisodium Tridecachlorotritungstate

C. Tris(Benzyltributylammonium) Tridecachlorotritungstate

References

6. Crystalline and Amorphous Forms of Tungsten Tetrachloride

A. Crystalline Tungsten Tetrachloride by Solid-State Reduction

B. Amorphous Tungsten Tetrachloride by Solution-Phase Reduction

References

Chapter Two: Cyclopentadienyl Compounds

7. Sodium and Potassium Cyclopentadienide

A. Sodium Cyclopentadienide

B. Potassium Cyclopentadienide

References

8. (Pentafluorophenyl)Cyclopentadiene and ITS Sodium Salt

A. (Pentafluorophenyl)Cyclopentadiene

B. Sodium (Pentafluorophenyl)Cyclopentadienide

References

9. BIS(η5-Pentamethylcyclopentadienyl) Complexes of Scandium

A. Bis(η5-Pentamethylcyclopentadienyl)Chloroscandium

B. Bis(η5-Pentamethylcyclopentadienyl)Methylscandium

C. Bis(η5-Pentamethylcyclopentadienyl)Phenylscandium

D. Bis(η5-Pentamethylcyclopentadienyl)(o-Tolyl)Scandium

References

10. Bis(η5-Pentamethylcyclopentadienyl) Complexes of Titanium, Zirconium, and Hafnium

A. Bis(η5-Pentamethylcyclopentadienyl)Dichlorotitanium(IV)

B. Bis(η5-Pentamethylcyclopentadienyl)Dichlorozirconium(IV)

C. Bis(η5-Pentamethylcyclopentadienyl)Dichlorohafnium(IV)

References

11. Bis(η5-Pentamethylcyclopentadienyl) Complexes of Niobium and Tantalum

A. Bis(η5-Pentamethylcyclopentadienyl)Dichlorotantalum(IV)

B. Bis(η5-Pentamethylcyclopentadienyl)Dichloroniobium(IV)

References

12. Bis(η5-Pentamethylcyclopentadienyl) Complexes of Molybdenum

A. Bis(Pentamethylcyclopentadienyl)Dichloromolybdenum(IV)

B. Bis(Pentamethylcyclopentadienyl)Dihydridomolybdenum(IV)

References

13. (η5-Cyclopentadienyl)Tricarbonylmanganese(I) Complexes

A. (η5-Cyclopentadienyl)Tricarbonylmanganese(I)

B. (η5-Pentamethylcyclopentadienyl)Tricarbonylmanganese(I)

References

14. 1,1′-Diaminoferrocene

A. 1,1′-Dilithioferrocene N,N,N′,N′-Tetramethylethylenediamine

B. 1,1′-Dibromoferrocene

C. One-Pot Preparation of 1,1′-Dibromoferrocene From Ferrocene

D. 1,1′-Diaminoferrocene

E. 1,1′-Diaminoferrocenium Hexafluorophosphate

F. 1,1′-Diaminoferrocenium Triflate

References

15. Mono(η5-Pentamethylcyclopentadienyl) Complexes of Osmium

A. Bromoosmic Acid

B. Bis(η5-Pentamethylcyclopentadienyl)Tetrabromodiosmium(III)

C. (η5-Pentamethylcyclopentadienyl)(1,5-Cyclooctadiene)Bromoosmium(II)

References

Chapter Three: Compounds with Metal–metal Bonds

16. Tetra(Acetato)Dimolybdenum(II)

References

17. Supramolecular Arrays Based on Dimolybdenum Building Blocks

A. Tetrakis(N,N′-Di-p-Anisylformamidinato)-Dimolybdenum(II)

B. Tris(N,N′-Di-p-Anisylformamidinato)Di(Chloro)-Dimolybdenum(II,III)

C. cis-Bis(N,N′-DI-p-Anisylformamidinato)Tetrakis(Acetonitrile)Dimolybdenum(II) Bis(Tetrafluoroborate)

D. (μ2-Succinato)Bis[Tris(N,N′-Di-p-Anisylformamidinato)-Dimolybdenum(II)]

E. (μ2-η2,η2-Molybdato)Bis[Tris(N,N′-Di-p-Anisylformamidinato)Dimolybdenum(II)]

F. (μ2-N,N′-Diphenylterephthaloyldiamidato)Bis[Tris-(N,N′-Di-p-Anisylformamidinato)Dimolybdenum(II)]

G. Molecular Propeller: (μ3-Trimesate)Tris[Tris(N,N′-Di-p-Anisylformamidinato)Dimolybdenum(II)]

H. Molecular Loop: closo-Bis(μ2-Malonato)Bis[Bis(N,N′-Di-p-Anisylformamidinato)Dimolybdenum(II)]

I. Molecular Triangle: closo-Tris(μ2-eq,eq-1,4-Cyclohexanedicarboxylato)Tris[Bis(N,N′-DI-p-Anisylformamidinato)Dimolybdenum(II)]

J. Molecular Square: closo-Tetrakis(μ2-Oxalato)-Tetrakis[Bis(N,N′-Di-p-Anisylformamidinato)-Dimolybdenum(II)]

K. Molecular Cage: closo-Tetrakis(μ3-Trimesate)Hexakis-[Bis(N,N′-Di-p-Anisylformamidinato)Dimolybdenum(II)]

References

18. Dimolybdenum and Ditungsten Hexa(Alkoxides)

A. Hexa(tert-Butoxy)Dimolybdenum(III)

B. Hexakis(2-Trifluoromethyl-2-Propoxy)-Dimolybdenum(III)

C. Sodium Heptachloropentakis(Tetrahydrofuran)Ditungstate(III)

D. Hexa(tert-Butoxy)Ditungsten(III)

E. Hexakis(2-Trifluoromethyl-2-Propoxy)Ditungsten(III)

References

19. Linear Trichromium, Tricobalt, Trinickel, and Tricopper Complexes Of 2,2′-Dipyridylamide

A. Dichlorotetrakis(2,2′-Dipyridylamido)-Trichromium(II)

B. Dichlorotetrakis(2,2′-Dipyridylamido)Tricobalt(II)

C. Dichlorotetrakis(2,2′-Dipyridylamido)Trinickel(II)

D. Dichlorotetrakis(2,2′-Dipyridylamido)Tricopper(II)

E. Bis(Acetonitrile)Tetrakis(2,2′-Dipyridylamido)-Trichromium(II) Bis(Hexafluorophosphate)

F. Bis(Acetonitrile)Tetrakis(2,2′-Dipyridylamido)-Tricobalt(II) Bis(Hexafluorophosphate)

G. Bis(Acetonitrile)Tetrakis(2,2′-Dipyridylamido)-Trinickel(II) Bis(Hexafluorophosphate)

References

20. Bis(Tetrabutylammonium) Octachloroditechnetate(III)

A. Tetrabutylammonium Pertechnetate(VII)

B. Tetrabutylammonium Oxotetrachlorotechnetate(V)

C. Bis(Tetrabutylammonium) Octachloroditechnetate(III)

References

21. Diruthenium Formamidinato Complexes

A. Chlorotris(Acetato)(N,N′-Di-2,6-Xylylformamidinato)-Diruthenium(II,III)

B. trans-Chlorobis(Acetato)Bis(N,N′-Di-2,6-Xylylformamidinato) Diruthenium(II,III)

C. cis-Chlorobis(Acetato)Bis(N,N′-Di-p-Anisylformamidinato)Diruthenium(II,III)

D. Chloro(Acetato)Tris(N,N′-Di-p-Anisylformamidinato)-Diruthenium(II,III)

E. Chlorotetrakis(N,N′-Di-p-Anisylformamidinato)-Diruthenium(II,III)

References

22. Heptacarbonyl(Disulfido)Dimanganese(I)

References

23. Di(Carbido)Tetracosa(Carbonyl)-Decaruthenate(2--) Salts

A. Calcium Di(Carbido)Tetracosa(Carbonyl)-Decaruthenate(2−)

B. Bis[Bis(Triphenylphosphoranylidene)Ammonium] Di(Carbido)Tetracosa(Carbonyl)Decaruthenate(2−)

References

Chapter Four: General Transition Metal Compounds

24. Bis(1,2-Bis(Dimethylphosphano)Ethane)Tricarbonyltitanium(0) and Hexacarbonyltitanate(2−)

A. Bis(1,2-Bis(Dimethylphosphano)Ethane)-Tricarbonyltitanium(0)

B. Bis[18-Crown-6)(Acetonitrile)Potassium] Hexacarbonyltitanate(2−)

References

25. Tungsten Benzylidyne Complexes

A. Trichloro(1,2-Dimethoxyethane)-Benzylidynetungsten(VI)

B. Chloro Bis[1,2-Bis(Diphenylphosphino)Ethane]-Benzylidynetungsten(IV)

References

26. Tungsten Oxytetrachloride and (Acetonitrile)Tetrachlorotungsten Imido Complexes

A. Tungsten Oxytetrachloride

B. (Acetonitrile)Tetrachloro(Phenylimido)-Tungsten(VI)

C. (Acetonitrile)Tetrachloro(2-Propylimido)-Tungsten(VI)

D. (Acetonitrile)Tetrachloro(2-Propenylimido)-Tungsten(VI)

References

27. Tungsten Oxytetrachloride and Several Tungstate Salts

A. Tungsten Oxytetrachloride

B. Bis(Tetrabutylammonium) Hexapolytungstate

C. Di(Cetylpyridinium) Peroxoditungstate

D. Bis(Tetrabutylammonium) Phenylphosphonatodiperoxotungstate

References

28. Bromotricarbonyldi(Pyridine)Manganese(I)

References

29. Bis(Tetraethylammonium) fac-Tribromotricarbonylrhenate(I) and -Technetate(I)

A. Bis(Tetraethylammonium) fac-Tribromotricarbonylrhenate(I)

B. Bis(Tetraethylammonium) fac-Trichlorotricarbonyltechnetate(I)

References

30. Methyl(OXO)Rhenium(V) Complexes with Chelating Ligands

A. Methyl(OXO)(1,2-Ethanedithiolato)Rhenium(V) Dimer

B. Methyl(OXO)Bis(2-Oxyquinoline)Rhenium(V)

C. Methyl(OXO)(2,2′-Thiodiacetato)(Triphenylphosphine)Rhenium(V)

References

31. Hexahydridoferrate(II) Salts

A. Tetrakis[Bromobis(Tetrahydrofuran)Magnesium] Hexahydridoferrate(II)

B. Tetrakis[2-Methyl-2-Propoxomagnesium] Hexahydridoferrate(II)

References

32. Tris(Allyl)Iridium and -Rhodium

A. Allyllithium

B. mer-Trichlorotris(Tetrahydrothiophene)Iridium(III)

C. mer-Trichlorotris(Tetrahydrothiophene)-Rhodium(III)

D. Tris(Allyl)Iridium(III)

E. Tris(Allyl)Rhodium(III)

References

33. Trinuclear Palladium(II) Acetate

References

Chapter Five: Main Group Compounds and Ligands

34. Monocarbaborane Anions with 10 or 12 Vertices

A. Tetraethylammonium arachno-6-Carba-Decaboranate(14)

B. Tetraethylammonium closo-2-Carba-Decaboranate(10)

C. Tetraethylammonium closo-1-Carba-Decaboranate(10)

D. Tetraethylammonium closo-1-Carba-Dodecaboranate(12)

E. Tetraethylammonium nido-6-Phenyl-6-Carba-Decaboranate(12)

F. Tetraethylammonium closo-2-Phenyl-2-Carba-Decaboranate(10)

G. Tetraethylammonium closo-1-Phenyl-1-Carba-Decaboranate(10)

H. Tetraethylammonium closo-1-Phenyl-1-Carba-Dodecaboranate(12)

References

35. Tetrakis(5-tert-Butyl-2-hydroxyphenyl)ethene

A. 5,5′-Di-tert-Butyl-2,2′-Dimethoxybenzophenone

B. Titanium Trichloride 1,2-Dimethoxyethane (1:1.5)

C. Tetrakis(5-tert-Butyl-2-Methoxyphenyl)Ethene

D. Tetrakis(5-tert-Butyl-2-Hydroxyphenyl)Ethene

References

36. Electrochemical Synthesis of Tetraethylammonium Tetrathiooxalate

References

37. Mid-Infrared Emitting Lead Selenide Nanocrystal Quantum Dots

A. Lead Selenide NQDs Emitting at 2.5 μm (0.50 eV)

B. Lead Selenide NQDs Emitting at 2.8 μm (0.44 eV)

C. Lead Selenide NQDs Emitting at 3.3 μm (0.38 eV)

D. Lead Selenide NQDs Emitting at 3.5 μm (0.35 eV)

References

Chapter Six: Teaching Laboratory Experiments

38. Tetra(Acetato)Dichromium(II) Dihydrate

References

39. Keggin Structure Polyoxometalates

A. Tri(Ammonium) 12-Molybdophosphate

B. 12-Tungstosilicic Acid

C. 12-Tungstophosphoric Acid

D. 12-Molybdophosphoric Acid

References

40. Quadruply Metal–Metal Bonded Complexes of Rhenium(III)

A. Tetrabutylammonium Perrhenate(VII)

B. Bis(Tetrabutylammonium) Octachlorodirhenate(III)

C. Tetra(Acetato)Dichlorodirhenium(III)

References

41. Bis[Bis(triphenylphosphoranylidene)ammonium] Undecacarbonyltriferrate(2−)

References

42. Acetylide Complexes of Ruthenium

A. (Cyclopentadienyl)Bis(Triphenylphosphine)-Chlororuthenium(II)

B. (Cyclopentadienyl)Bis(Triphenylphosphine)-(Phenylacetylido)Ruthenium(II)

References

43. N,N′-Bis(Mercaptoethyl)-1,4-Diazacycloheptane (H2Bme-Dach) and Its Nickel Complex: A Model for Bioinorganic Chemistry

A. [N,N′-Bis(2-Mercaptidoethyl)-1,4-Diazacycloheptane]-Nickel(II)

B. Sulfur Dioxide Adduct of NiII(BME-DACH)

C. Acetylation of NiII(BME-DACH)

References

44. Tin(II) Iodide

References

45. N-tert-BUTYL-3,5-dimethylaniline

A. 2,4,6-Trimethylpyrylium Tetrafluoroborate

B. N-tert-Butyl-3,5-Dimethylaniline

References

Cumulative Contributor Index

Cumulative Subject Index

Cumulative Formula Index

End User License Agreement

List of Tables

Table 1.

List of Illustrations

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Scheme 1.

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Scheme 1.

Scheme 1.

Figure 1.

Figure 1.

Guide

Cover

Table of Contents

Preface

Chapter 1

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Board of Directors

THOMAS B. RAUCHFUSS, President University of Illinois at Urbana-Champaign

MARCETTA Y. DARENSBOURG Texas A&M University

GREGORY S. GIROLAMI University of Illinois at Urbana-Champaign

ALFRED P. SATTELBERGER Argonne National Laboratory

JOHN R. SHAPLEY University of Illinois at Urbana-Champaign

Secretary to the Corporation

STANTON CHING Connecticut College

Future Volumes

37 PHILIP P. POWER University of California at Davis

International Associates

MARTIN A. BENNETT Australian National University

MALCOLM L. H. GREEN Oxford University

JAN REEDIJK Leiden University

HERBERT W. ROESKY University of Göttingen

WARREN R. ROPER University of Auckland

Inorganic Syntheses

Volume 36

Editors-in-Chief

Gregory S. Girolami

University of Illinois at Urbana-Champaign

Alfred P. Sattelberger

Argonne National Laboratory

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Library of Congress Catalog Number: 39:23015

ISBN 978-1-118-74487-1

Preface

This volume of Inorganic Syntheses spans the preparations of a wide range of important inorganic, organometallic, and solid-state compounds. Continuing a long-standing tradition, we have emphasized useful compounds and methods. Reflecting our own personal research interests, transition metal halides, complexes with cyclopentadienyl and substituted cyclopentadienyl ligands, and compounds with metal–metal bonds are featured. We have also included a chapter on pedagogically important compounds that we hope will find their way into undergraduate inorganic chemistry teaching laboratories.

The volume is divided into six chapters. Chapter 1 contains the syntheses of some key early transition metal halide clusters and the very useful mononuclear molybdenum(III) synthon, MoCl3(THF)3. This set of procedures was submitted by Lou Messerle and Rinaldo Poli. Chapter 2 covers the synthesis of a number of cyclopentadienyl compounds, including a novel route to sodium and potassium cyclopentadienide, MC5H5. Special thanks are due to John Bercaw, Endy Min, and Ged Parkin for the syntheses of the bis(pentamethylcyclopentadienyl) compounds of groups 3, 4, 5, and 6. Chapter 3 details synthetic procedures for a range of metal–metal bonded compounds, including several with metal–metal multiple bonds. Special thanks here are due to Al Cotton, Carlos Murillo, and Dick Walton. Chapter 4 contains procedures for a range of early and late transition metal compounds, each a useful synthon for further synthetic elaboration. Chapter 5 deals with the synthesis of a number of main group compounds and ligands, while Chapter 6 covers teaching laboratory experiments. The editors are grateful to Marcetta Darensbourg for suggesting the teaching chapter.

We would like to thank everyone who submitted syntheses for Volume 36 and the checkers who dedicated considerable time and effort in checking the procedures. We acknowledge the long delay in getting this volume published and thank the contributors and checkers for their patience. To those contributors who will not see their syntheses in this volume, we apologize for not being able to find an individual willing or able to check their syntheses. We wish to extend special thanks to Vera Mainz for her expert help in the preparation of the cumulative indices that appear at the end of this volume. We undertook this large project in the hope that readers will find this material to be useful aids to locating recipes that have appeared since the last cumulative index, which summarized content up through volume 30 of Inorganic Syntheses.

Finally, we would like to thank our friend and colleague Tom Rauchfuss for his tireless encouragement and advice, and our mentors Dick Andersen and Geoff Wilkinson (for GSG) and Ward Schaap and John Fackler (for APS) who taught us both the joys and challenges of synthetic inorganic chemistry.

Alfred P. Sattelberger

Argonne National Laboratory

Gregory S. Girolami

University of Illinois at Urbana-Champaign

Dedication

This volume is dedicated to the memory of eight eminent chemists who made outstanding contributions to inorganic chemistry in general and to Inorganic Syntheses in particular. We also note the recent passing of two other inorganic chemists, Bill Lipscomb and Gordon Stone, who were not former volume editors but whose contributions to inorganic chemistry were significant. Each was a talented synthetic chemist in his own right, and all helped shape the discipline we know and love.

George Therald Moeller (Editor-in-Chief, Volume V, 1957)

Therald Moeller was born in North Bend, Oregon, on April 3, 1913, and died in Broken Arrow, Oklahoma, on November 24, 1997, at the age of 84. In 1934, he graduated from Oregon State College (now Oregon State University) in Corvallis as the top student of his senior class, having majored in chemical engineering. In 1938, he received his Ph.D. degree in inorganic and physical chemistry from the University of Wisconsin, Madison, for a thesis titled “A Study of the Preparation and Certain Properties of Hydrous Lanthanum Oxide Sols,” carried out under the direction of Francis C. Krauskopf. Therald was Instructor in Chemistry at Michigan State College (now Michigan State University) at East Lansing (1938–1940), but in 1940 he moved to the University of Illinois, Urbana-Champaign. In 1969, Therald became Chair of the Department of Chemistry at Arizona State University in Tempe, serving in this capacity until 1975. He retired as Professor Emeritus in 1983.

Therald became an internationally recognized authority on the chemistry of the rare earth elements (lanthanides) and published 94 research papers and books in this area alone. During his 45 years of teaching and research, he guided the laboratory research of 43 Ph.D. students, 20 postdoctoral fellows, and 11 M.S. and 25 B.S. students for a total of 99 research students in inorganic chemistry. Of these, at least 39 became professors themselves at universities in the United States, Taiwan, Spain, India, Japan, Brazil, England, and Finland. Several became Department Chairs and one a College President.

Therald's 281 publications include 22 books and laboratory manuals authored or edited by him (32 books if Spanish, Russian, Japanese, Italian, and Polish editions are counted). One of these texts, Inorganic Chemistry, An Advanced Text (Wiley, 1952), was the “bible” of inorganic chemistry for decades, enjoying widespread adoption (I used it in my first inorganic chemistry class in 1956). Until its appearance, few U.S. universities taught inorganic courses more advanced than the freshman level because only foreign texts were available, and none of these were satisfactory. As soon as Therald's text appeared, universities began to teach advanced inorganic chemistry, which immensely influenced its development in the United States and around the world. Along with John C. Bailar Jr. (Editor-in-Chief, Volume IV, 1953), Therald cofounded the ACS Division of Inorganic Chemistry (1956), serving as its Chair in 1961–1962. He also served for many years as a member of the Board of Directors of Inorganic Syntheses, Inc.

Eugene George Rochow (Editor-in-Chief, Volume VI, 1960)

Gene Rochow was born in Newark, New Jersey, on October 4, 1909, and died in Fort Myers, Florida, on March 21, 2002, at the age of 92. He spent his childhood in Maplewood, New Jersey, where he displayed an interest in electricity and the early use of silicon as a crystal detector in radio sets. Gene followed his brother Theodore as a chemistry assistant both in high school and at Cornell University, Ithaca, New York. He was a lecture and laboratory assistant to Louis M. Dennis, Chairman of the Chemistry Department at Cornell, under whom he received his B.S. (1931) and Ph.D. degrees (1935), the latter for a thesis titled “Contributions to the Chemistry of Fluorine.” Gene also worked as a special assistant to Alfred Stock, who spent several months in 1932 at Cornell as Baker Lecturer. From Stock he first learned about the chemistry of silicon hydrides, and in fact was responsible for drawing the diagrams for Stock's famous book, The Hydrides of Boron and Silicon, which was written during that time.

After a summer job as Research Chemist at the Halowax Corporation, New York City (1931–1932), and as a Lecture Assistant at Cornell (1932–1935), Gene found summer employment with the Hotpoint Company, a General Electric Company subsidiary. He later became a Research Associate at the General Electric Research Laboratory, Schenectady, New York (1935–1948). His most notable discovery there was a process to produce methylchlorosilanes, the precursors to silicones, from methyl chloride and a silicon/copper alloy, a process still used on a large scale today. He continued his research on silicone production until his transfer to Richland, Washington, where he conducted research on nuclear fission as a source of domestic energy. When the U.S. Government requested that GE work on nuclear propulsion for naval vessels, Gene, a Quaker, left in 1948 to teach chemistry at Harvard University, where he remained until retiring in 1970. His 1949 Baekeland address called for conservation, recycling, and the use of less wasteful alternatives long before these became fashionable. In the early 1950s, he became the first to apply broad-line NMR to the study of dynamic motion in silicone polymers. His interest in the differences in the chemistry of the group 14 elements led to work that culminated in the Allred–Rochow electronegativity scale, which can be found in many current textbooks.

Gene was the author or coauthor of several influential books, including Chemistry of the Silicones (1946, 1951), General Chemistry—A Topical Introduction (1954), The Chemistry of Organometallic Compounds (1956), Unnatural Products (1960), Organometallic Chemistry (1964), Metalloids (1966), Chemistry—Molecules That Matter (1974), and Modern Descriptive Chemistry (1977). The holder of numerous U.S. and foreign patents on chemical processes and organometallic substances, Gene received many awards, including the Baekeland Medal, American Chemical Society (1949); the Meyer Award, American Ceramic Society (1951); the Perkin Medal, Society of Chemical Industry (London, 1962); election to the American Academy of Arts and Sciences (1962); the Honor Scroll, American Institute of Chemists (1964); the Frederick Stanley Kipping Award, American Chemical Society (1965); the Chemical Pioneers Award, American Institute of Chemistry (1968); the Award for Excellence in Teaching, Manufacturing Chemists Association (1970); the James Flack Norris Award for the Teaching of Chemistry, American Chemical Society (1973); and the Alfred Stock Medal, German Chemical Society (1983).

Jacob Kleinberg (Editor-in-Chief, Volume VII, 1963)

Jake Kleinberg was born on February 14, 1914, in Passaic, New Jersey, and died on January 12, 2004, in Lawrence, Kansas, at the age of 89. He lost his father at the age of 3 and put himself through college by working part-time. Although initially enrolled at the City College of New York, he transferred to Randolph-Macon College, Ashland, Virginia, from which he received his B.S. degree in 1934. He earned his M.S. (1937) and Ph.D. degrees (1939) from the University of Illinois, Urbana-Champaign, under Ludwig F. Audrieth (Editor-in-Chief, Volume III, 1950), one of the founders and most prolific contributors to Inorganic Syntheses and a member of its Board of Editors (1934–1967). His thesis involved the ammonolysis of esters and the use of sulfamic acid in the separation of the rare earths. Jake was Assistant Professor at James Millikin University, Decatur, Illinois (1940–1943), and the College of Pharmacy at the University of Illinois, Chicago (1943–1946). In 1946, he joined the chemistry faculty of the University of Kansas, becoming Professor in 1951 and serving as Department Chairman from 1963 to 1970 before retiring in 1984. He was a Resident Lecturer for the National Science Foundation's summer institutes for high school chemistry teachers, led two committees that selected two Chancellors, and was President of the local chapter of Phi Beta Kappa.

Jake was the author of 95 scientific articles. He was the first to synthesize the ReH92− anion (although its composition would remain mysterious for many years), and carried out many studies of the electrochemical reduction of both inorganic and organic substances. The titles of his books reflect his primary interests: Unfamiliar Oxidation States and Their Stabilization (1950); Non-Aqueous Solvents: Applications as Media for Chemical Reactions (with Ludwig F. Audrieth, 1953); Inorganic Chemistry (with William James Argersinger Jr. and Ernest Griswold, 1960); University Chemistry (with John C. Bailar Jr. and Therald Moeller, 1965); Chemistry with Inorganic Qualitative Analysis (with Therald Moeller and John C. Bailar Jr., 1965); Introductory Analytical Chemistry (with Alexander I. Popov and Ronald T. Pflaum, 1966); and Radiochemistry of Iodine (with Milton Kahn, 1977).

The winner of the ACS Midwest Award and the Amoco Foundation Award for Distinguished Teaching, Jake was a consultant for the Los Alamos National Laboratory and a member of the Editorial Board of Chemical Reviews (1951–1953), the Journal of Inorganic & Nuclear Chemistry (founded in 1955), and Inorganic Chemistry (1961–1964).

Henry Fuller Holtzclaw Jr. (Editor-in-Chief, Volume VIII, 1966)

Henry Holtzclaw was born on July 30, 1921, in Stillwater, Oklahoma, and died in Lincoln, Nebraska, on May 24, 2001, after a long illness at the age of 79. He earned his A.B. degree in chemistry from the University of Kansas, Lawrence, in 1942, where his father was a Professor of Economics. While still a student, he was employed at the Eastman Kodak Company in Rochester, New York (summers of 1941 and 1942). He obtained his M.S. (1946) and Ph.D. degrees (1947) from the University of Illinois, Urbana-Champaign, under John C. Bailar Jr. (Editor-in-Chief, Volume IV, 1953). He participated in the Manhattan Project with the Tennessee Eastman Corporation in Oak Ridge, Tennessee (1944–1945), and his doctoral thesis was entitled “Polarographic Reduction of Cobaltic Coordination Complexes.” In 1947, Henry joined the Chemistry Department of the University of Nebraska, Lincoln, and rose through the ranks to become Professor. He was appointed Foundation Professor of Chemistry in 1967 and Dean of Graduate Studies from 1976 to 1985. He spent a sabbatical leave as Guest Professor to teach and carry out research at the Universität Konstanz in Germany. He retired from the University of Nebraska in 1988.

Henry's research interests encompassed mass spectroscopy, proton magnetic resonance, and polarography of coordination compounds especially metal complexes of chelates such as β-diketonates. He was the coauthor of three popular freshman chemistry textbooks, some of which went through as many as 10 editions: College Chemistry: With Qualitative Analysis (1963), General Chemistry (1972), and Basic Laboratory Studies in College Chemistry with Semi-Micro Quantitative Analysis (1986).

Henry served as Chair of the Test of English as a Foreign Language Research Committee of the Educational Testing Services in the 1980s. In 1995, he received the James A. Lake Academic Freedom Award in recognition of his role as Chairman of a committee investigating a faculty member who helped lead a student anti-war demonstration in 1971.

William Lee Jolly (Editor-in-Chief, Volume XI, 1968)

Bill Jolly was born in Chicago, Illinois, on December 27, 1927, and passed away at the age of 86 in Berkeley, California, on January 10, 2014. Bill received his B.S. (1948) and M.S. (1949) degrees from the University of Illinois at Urbana-Champaign, where he studied phosphate and hydrazine chemistry under the inorganic chemist Ludwig Audrieth (Editor-in-Chief, Volume III, 1950). He then moved to the University of California at Berkeley, where he obtained his Ph.D. degree under Wendell Latimer for work on the physical properties of germanium compounds. He was appointed for 1 year as an instructor at Berkeley in 1952 and then served as the Head of the Physical Chemistry and Inorganic Chemistry Division at the Radiation Laboratory in Livermore from 1952 until 1955. In the latter year, he returned to Berkeley as an Assistant Professor in the Chemistry Department, and was promoted to Associate Professor in 1957 and to Professor in 1962. He became Professor Emeritus in 1991.

Bill's research interests included thermodynamic and spectroscopic studies of liquid ammonia solutions, the synthesis of main group hydrides, and the chemistry of sulfur–nitrogen compounds, especially S4N4. In addition to work on the mechanism of hydrolysis of the borohydride ion, Bill developed improved routes to germane, stannane, arsine, and stibine. In the late 1960s and for the next 15 years, he carried out extensive and widely cited X-ray photoelectron spectroscopy (ESCA) studies of the chemical structure and bonding of inorganic compounds (especially those containing nitrogen and phosphorus) and organometallic compounds (especially metal carbonyls).

Among his other achievements, Bill wrote a highly entertaining history of the Chemistry Department at Berkeley called From Retorts to Lasers (1987). He was an expert in the chemistry of photography and invented a developer for the “solarization” of film, a technique that creates partly negative, partly positive photographic images. Among his awards was a Guggenheim Fellowship in 1959–1960, which he spent at the Chemical Institute of the University of Heidelberg, Germany. He was elected a fellow of the American Association for the Advancement of Science in 1984.

He was a prodigious author, especially in the area of preparative inorganic chemistry, where his textbooks were widely used and influential. Among his books are Synthetic Inorganic Chemistry (1960), The Inorganic Chemistry of Nitrogen (1964), Preparative Inorganic Reactions (editor, 7 volumes, 1964–1971), The Chemistry of the Non-Metals (1966), The Synthesis and Characterization of Inorganic Compounds (1970), Metal-Ammonia Solutions (compiler, 1972), Encounters in Experimental Chemistry (1972, 1985), Principles of Inorganic Chemistry (1976), Modern Inorganic Chemistry (1985, 1991, 1998), and Solarization Demystified (unpublished, 1997).

John Keen Ruff (Co-Editor-in-Chief, Volume XIV, 1973)

John was born on February 19, 1932, in New York City and died on January 6, 2004, in Athens, Georgia, of cancer at the age of 71. He received his B.S. degree in 1954 from Haverford College in Haverford, Pennsylvania, where he worked on hormones in his honors work. He obtained his Ph.D. degree from the University of North Carolina, Chapel Hill, in 1959 for a dissertation, “Light-Scattering of Aqueous Aluminum Nitrate and Gallium Perchlorate Solutions,” that was supervised by S. Young Tyree (Editor-in-Chief, Volume IX, 1967). He then worked for 10 years at Redstone Arsenal, a research unit at Huntsville, Alabama, operated by the Rohm & Haas Company. In 1969, he moved to the University of Georgia, Athens, where he was a faculty member for 27 years.

John specialized in fluorine, boron, sulfur, phosphorus, and metal carbonyl chemistry. With M. Frederick Hawthorne, he discovered a series of amine complexes of aluminum trihydride and showed that some of them give aluminum metal when heated; this process later became useful for the formation of aluminum thin films by chemical vapor deposition. One of his notable achievements was the discovery that the PPN cation, bis(triphenylphosphoranylidene) ammonium, forms air-stable salts with many air-sensitive anions such as [Co(CO)4]−. He also discovered that cesium fluoride can serve as a catalyst for the synthesis of organic fluoroxy compounds (RFOF) by the fluorination of acyl halides.

He wrote three editions (1995, 1998, 2001) of the laboratory manual Experiments in General, Organic and Biological Chemistry (coauthor Bobby Stanton). John was awarded a Sloan Research fellowship in 1969 and was a longtime member of the Atlanta Yacht Club.

Duward Felix Shriver (Editor-in-Chief, Volume XIX, 1979)

Duward (“Du”) F. Shriver was born on November 20, 1934, in Glendale, California, and died on March 6, 2013, in Evanston, Illinois. He was raised on Oahu in the Hawaiian Islands, received his undergraduate degree in 1958 from the University of California, Berkeley, working with William L. Jolly (Editor-in-Chief, Volume XI, 1968), and his Ph.D. degree in 1961 from the University of Michigan, working with Robert W. Parry (Editor-in-Chief, Volume XIII, 1972). Du spent his entire academic career at Northwestern, beginning in 1961. He was named Morrison Professor of Chemistry in 1987 and served as Chemistry Department Chair from 1992 to 1995.

Du published more than 400 scientific articles spanning inorganic and organometallic synthesis, bioinorganic, solid-state and polymer chemistry, and vibrational spectroscopy. Some of his more notable achievements were the stepwise protonation of a carbonyl ligand to form methane and the isolation of cluster compounds containing the ketenylidene ligand; both of these systems are relevant to the industrially important Fischer–Tropsch process. He also made significant contributions to the design and synthesis of new polymers for lithium ion batteries and the vibrational signature of metal dioxygen compounds.

Du's book The Manipulation of Air-Sensitive Compounds (1969, 1986) is a standard reference in the field of organometallic chemistry, and he coedited The Chemistry of Metal Cluster Compounds (1990) with Herbert D. Kaesz (Editor-in-Chief, Volume XXVI, 1989) and Richard D. Adams. His highly successful undergraduate textbook Inorganic Chemistry (1990, 1994, 1999, 2006), coauthored with Peter W. Atkins, has been translated into 10 languages and is used to teach this very broad and important subject to students around the world. Du mentored more than 150 students and postdoctoral students who went on to pursue careers in industry and government and at national laboratories, colleges, and universities.

He received many professional awards, including a Guggenheim Fellowship, an Alfred P. Sloan Research Fellowship, the Royal Society of Chemistry Ludwig Mond Medal, the Materials Research Society Medal, and the American Chemical Society Award for Distinguished Service in Inorganic Chemistry. He was a fellow of the American Association for the Advancement of Science.

Herbert David Kaesz (Editor-in-Chief, Volume XXVI, 1989)

Herb Kaesz was born on January 4, 1933, in Alexandria, Egypt, to Austrian parents and died on February 26, 2012, in Los Angeles, California, at the age of 79, about a month after he had been diagnosed with cancer. His father, a chemist, had joined his wife's family business, Kurz Optical, to run the Alexandria branch. When Herb was 7, the family emigrated to the United States. He received his A.B. degree from New York University in 1954 with Phi Beta Kappa honors. He earned his M.A. (1956) and Ph.D. degrees (1959) from Harvard University under the supervision of F. Gordon Stone for work on molecular addition compounds of boron. In August 1960, Herb joined the Inorganic Division of the University of California, Los Angeles (UCLA), where he served until his retirement in 2003. He remained an active Professor Emeritus until his death.

Herb's research centered on the synthesis and applications of organometallic compounds, especially metal carbonyls. In 1961, he synthesized Tc2(CO)10, which completed the list of elements, 14 in number, that form isolable binary carbonyls in the zero oxidation state. He discovered many new metal hydride and cluster compounds, and carried out elegant investigations of the nucleophilic activation of coordinated CO ligands under mild conditions. His book, The Chemistry of Metal Cluster Complexes (1990), coauthored with Duward F. Shriver (Editor-in-Chief, Volume XIX, 1979) and Richard D. Adams, became the premier reference text on the topic. He also studied main group element compounds and, later in his career, he investigated the development of pyrolytic and photolytic methods of metal film deposition for electronic applications.

He served as Chair of the International Union of Pure and Applied Chemistry (IUPAC) Commission on the Nomenclature of Inorganic Chemistry, was President of Inorganic Syntheses, Inc., and served for more than three decades as Associate Editor of the ACS journal, Inorganic Chemistry (1969–2001). Herb's honors included the ACS Southern California Section's Tolman Medal (1981), a Fellowship of the American Association for the Advancement of Science (1988), and the ACS Award for Distinguished Service in the Advancement of Inorganic Chemistry (1998). In 2009, the inaugural year of the program, he was elected an ACS Fellow. Herb held two foreign fellowships—a Fellowship from the Japan Society for the Promotion of Science (1978) and a Senior U.S. Scientist Award from the Alexander von Humboldt Foundation in Germany (1988). He also twice held the post of Professeur Invité in France, once in Toulouse (1992) and once in Paris (1995).

George B. Kauffman

California State University, Fresno, CA

Notice to Contributors and Checkers

The Inorganic Syntheses series (www.inorgsynth.com) publishes detailed and independently checked procedures for making important inorganic and organometallic compounds. Thus, the series is the concern of the entire scientific community. The Editorial Board hopes that many chemists will share in the responsibility of producing Inorganic Syntheses by offering their advice and assistance in both the formulation and the laboratory evaluation of outstanding syntheses.

The major criterion by which syntheses are judged is their potential value to the scientific community. We hope that the syntheses will be widely used and provide access to a broad range of compounds of importance in current research. The syntheses represent the best available procedures, and new or improved syntheses of well-established compounds are often featured. Syntheses of compounds that are available commercially at reasonable prices are ordinarily not included, however, unless the procedure illustrates some useful technique. Inorganic Syntheses is not a repository of primary research data, and therefore submitted syntheses should have already appeared in some form in the primary peer-reviewed literature and, at least to some extent, passed the “test of time.” The series offers authors the chance to describe the intricacies of synthesis and purification in greater detail than possible in the original literature, as well as to provide updates of an established synthesis.

Authors wishing to submit syntheses for possible publication should write their manuscripts in a style that conforms with that of previous volumes of Inorganic Syntheses (a style guide is available from the Board Secretary). The manuscript should be in English and submitted as an editable electronic document. Nomenclature should be consistent and should follow the recommendations presented in Nomenclature of Inorganic Chemistry, IUPAC Recommendations 2005, published for the International Union of Pure and Applied Chemistry by The Royal Society of Chemistry, Cambridge, 2005. This document is available online (as of 2012) at http://www.iupac.org/fileadmin/user_upload/databases/Red_Book_2005.pdf. Abbreviations should conform to those used in publications of the American Chemical Society, particularly Inorganic Chemistry.

Submissions should consist of four sections: Introduction, Procedure, Properties, and References. The Introduction should include an indication of the importance and utility of the product(s) in question, and a concise and critical summary of the available procedures for making them and what advantage(s) the chosen method has over the alternatives. The Procedure should present detailed and unambiguous laboratory directions and be written so that it anticipates possible mistakes and misunderstandings on the part of the person who attempts to duplicate the procedure. It should contain an admonition if any potential hazards are associated with the procedure, and what safety precautions should be taken. Sources of unusual starting materials must be given, and, if possible, minimal standards of purity of reagents and solvents should be stated. Ideally, all reagents are readily available commercially or have been described in earlier volumes of Inorganic Syntheses. The scale should be reasonable for normal laboratory operation, and problems involved in scaling the procedure either up or down should be discussed if known. Unusual equipment or procedures should be clearly described and, if necessary for clarity, illustrated in line drawings. The yield should be given both in mass and in percentage based on theory. The Procedure section normally will conclude with calculated and found microanalytical data. The Properties section should supply and discuss those physical and chemical characteristics that are relevant to judging the purity of the product and to permitting its handling and use in an intelligent manner. Under References, pertinent literature citations should be listed in the order they appear in the text.

Manuscripts should be submitted electronically to the Secretary of the Editorial Board, Professor Stanton Ching, [email protected]. The Editorial Board determines whether submitted syntheses meet the general specifications outlined above. Every procedure will be checked in an independent laboratory, and publication is contingent on satisfactory duplication of the syntheses. For online access to information and requirements, see www.inorgsynth.com.

Chemists willing to check syntheses should contact the editor of a future volume or make this information known to Professor Ching.

Toxic Substances and Laboratory Hazards

Chemicals and chemistry are by their very nature hazardous. The obvious hazards in the syntheses reported in this volume are delineated, where appropriate, in the experimental procedure. It is impossible, however, to foresee every eventuality, such as a new biological effect of a common laboratory reagent. As a consequence, all chemicals used and all reactions described in this volume should be viewed as potentially hazardous. Care should be taken to avoid inhalation or other physical contact with reagents and solvents used in this volume. In addition, particular attention should be paid to avoiding sparks, open flames, or other potential sources that could set fire to combustible vapors or gases.

The following sources are especially recommended for guidance:

NIOSH Pocket Guide to Chemical Hazards

, U.S. Government Printing Office, Washington, DC, 2005 (ISBN-13: 978-1-59804-052-4), is available free at

http://www.cdc.gov/niosh/npg/

and can be purchased in paperback and spiral bound format. It contains information and data for 677 common compounds and classes of compounds.

Organic Syntheses

, which is available online at

http://www.orgsyn.org

, has a concise but useful section “Handling Hazardous Chemicals.”

Prudent Practices in the Laboratory: Handling and Disposal of Chemicals

, National Academy Press, 1995 (ISBN-13: 978-0-30905-229-0), is available free at

http://www.nap.edu/catalog.php?record_id=4911

.

W. L. F. Amarego and C. Chai,

Purification of Laboratory Chemicals

, 6th ed., Butterworth-Heinemann, Oxford, 2009 (ISBN-13: 978-1-85617-567-8), is the standard reference for the purification of reagents and solvents. Special attention should be paid to the purification and storage of ethers.

Chapter OneTransition Metal Halide Compounds

1. Octahedral Hexatantalum Halide Clusters

Submitted by Thirumalai Duraisamy,1 Daniel N. T. Hay,1 and Louis Messerle1Checked by Abdessadek Lachgar2

Octahedral hexatantalum halide clusters usually exist as extended structures of the form Ta6(μ-X)12X2 with terminal (outer) and bridging (inner) halogen atoms shared between clusters, or as discrete clusters such as Ta6(μ-X)12X2·8H2O that are better formulated as Ta6(μ-X)12X2(OH2)4·4H2O. These clusters consist of six tantalums linked through Ta—Ta bonding to form a Ta6 octahedron with a halide bridge along each of the 12 octahedral edges and one terminal ligand (halide, water, etc.) located apically on each tantalum.1 A range of cluster oxidation states have been reported.2

Ta6Cl14 was first reported in 1907 from the reduction of Ta2Cl10 (denoted as TaCl5 hereafter) with sodium amalgam,3 and its structure was determined in 1950.4 It is prepared typically by high-temperature, solid-state reduction of TaCl5 in vacuum-sealed quartz ampules.5 Microwave heating has also been employed.6 Extraction with large volumes of water gives good yields of the discrete cluster7 Ta6(μ-Cl)12Cl2(OH2)4·4H2O after aqueous reduction of oxidized cluster contaminants with SnCl2. The most commonly used approach is that developed by Koknat et al., involving reduction at 700°C of TaCl5 with a four-fold excess of Ta powder.8

Ta6Br14 was first prepared in 1910 by sodium amalgam reduction of TaBr5.3b It has since been prepared by using the reductants aluminum5a and excess tantalum8a and can be isolated by aqueous extraction as the discrete cluster Ta6(μ-Br)12Br2(OH2)4·4H2O.2a,b A sample was structurally characterized as [Ta6(μ-Br)12(OH2)6](OH)Br·4H2O,9 and another structure of the hexaaquo ion [Ta6(μ-Br)12(OH2)6]2+ was recently reported.10

There is considerable interest in the coordination11 and catalytic12 chemistries of these discrete clusters. Because of its high electron count, the hexaaquo ion [Ta6(μ-Br)12(OH2)6]2+ has been used frequently for phase determination9,13 of isomorphous protein derivatives by SIR, MIR, SIRAS/MIRAS, and SAD/MAD methods in biomacromolecular crystallography. This use is growing as larger biomacromolecular structures and assemblies (e.g., membrane proteins, ribosomes, proteasomes) are studied.

We have found that the main group metal and metalloid reductants mercury, bismuth, and antimony are highly effective14 in reducing WCl6 or MoCl5 at surprisingly lower temperatures than commonly used in the solid-state synthesis of early transition metal cluster halides. Borosilicate ampules can be substituted for the more expensive and less easily sealed quartz ampules at these lower temperatures, and the metals and metalloids are not as impacted by oxide coatings that inhibit solid-state reactions with more active metals. These lower temperatures may allow access to kinetic products, such as trinuclear clusters, instead of thermodynamic products.

We report here an extension of this reduction methodology to the convenient preparation15 of Ta6(μ-X)12X2(OH2)4·4H2O by reduction of TaX5 with gallium dichloride, Ga+GaCl4− (for X = Cl), or gallium (for X = Br). Gallium dichloride has not been used as a preparative-scale reductant in transition metal chemistry. Gallium is an effective reductant, but because of its tendency to agglomerate and to adhere to glass, reductions employing Ga need to be agitated several times during the course of the reaction in order to optimize yields by homogenization of reactants. We have not yet tested the use of gallium dibromide as a reductant for TaBr5, but expect that it would eliminate the need to homogenize reactants in gallium-based reductions and might improve the yield. The aquated hexatantalum clusters are liberated from the solid-state products by Soxhlet extraction with water, which greatly simplifies the isolation procedure. We also describe the straightforward preparation of a tetraalkylammonium derivative of the [Ta6(μ-Cl)12Cl6]4− anion that has solubility in a broader array of organic solvents than the aquated clusters.

General Procedures

TaX5 (X = Cl, Br; Materion Advanced Chemicals, Milwaukee, WI), hydrochloric acid (12 M, Fisher Scientific), Ga (99.99%, Atlantic Equipment Engineers, Bergenfield, NJ), NaCl (Fisher), KBr (Aldrich Chemical), SnCl2·2H2O (Fisher), SnBr2 (99.5%, Alfa Aesar), HBr (48%, Fisher), and diethyl ether (anhydrous, Fisher) are used as received. Ga+GaCl4− is purchased and used as received from Alfa Aesar or is prepared by a literature method.16 Powder X-ray diffraction is performed on samples protected from moisture by a 5 μm polyethylene film. Reactants and solid-state products are handled in a glove box under a dinitrogen atmosphere. A tube furnace with a positionable thermocouple is used in conjunction with a temperature controller in order to maintain and ramp temperatures. Syntheses are performed in dual-chamber, 25 mm OD borosilicate glass ampules with 30–40 mL total chamber volume, a 14/20 ground glass joint at one end, and constrictions between the end reaction chamber and middle receiver chamber (for volatile by-products) and between the middle receiver chamber and ground joint (Fig. 1). Ampules are oven dried at 130°C overnight and brought directly while hot into the glove box and cooled under vacuum or dinitrogen. Reactants are thoroughly mixed (employing a vortex mixer to agitate the reactants in a 20 mL glass scintillation vial) and added to the end reaction chamber via a long-stem funnel that minimizes contamination of the constriction surfaces. A gas inlet adapter3 is used to seal the ampule, which is then evacuated on a Schlenk line and flame sealed between the joint and receiver chamber.

Figure 1. Ampule design for solid-state syntheses.

Tantalum is determined gravimetrically as the metal oxide Ta2O5. Samples are decomposed in tared borosilicate test tubes using concentrated nitric acid and hydrogen peroxide. The samples are dried and ignited. Other analyses are performed by Desert Analytics, Tucson, AZ.

A. Tetradecachlorohexatantalum Octahydrate

Procedure

A vacuum-sealed ampule with TaCl5 (0.96 g, 2.7 mmol), Ga2Cl4 (1.00 g, 3.56 mmol), and NaCl (0.52 g, 8.9 mmol) in the end reaction chamber is placed in the center of a 45° inclined tube furnace. The furnace is slowly heated to 500°C over 4 h and kept at 500°C for 24 h. After being cooled, the ampule is opened in air and the dark solid is ground to a green powder with a mortar and pestle. The hygroscopic green powder is transferred to a coarse fritted glass Soxhlet thimble (25 mm × 50 mm), containing a layer of borosilicate wool, the end packed with borosilicate wool, and the thimble is placed in a Soxhlet extractor. The apparatus is evacuated and backfilled with argon three times, and the powder is extracted (under argon to minimize air oxidation) for 17 h with argon-degassed distilled water (120 mL). The dark green solution is filtered through a medium-porosity fritted glass funnel in air, in order to remove insoluble white GaO(OH) powder (identified by powder X-ray diffractometry, matching PDF Card Number 06-0180). A solution of SnCl2·2H2O (1.0 g, 4.5 mmol) in 12 M hydrochloric acid (150 mL) is filtered to remove insoluble material, and a portion of this solution is added to the dark green filtrate, which is stirred and heated to near boiling, then cooled, and the remaining stannous chloride solution added. This step reduces any oxidized cluster contaminants to Ta6(μ-Cl)12Cl2(OH2)4·4H2O. The mixture is cooled in an ice bath, and the dark emerald green solid product is collected on a medium-porosity fritted glass funnel. The solid is washed with hydrochloric acid (20 mL), diethyl ether (30 mL), and dried in vacuum. Yield: 0.75 g (95%).

Anal. Calcd. for H16Cl14O8Ta6: Ta, 62.90; Cl, 28.75; Ga, 0.0. Found: Ta, 62.74; Cl, 28.70; Ga, <0.01.

Properties

Ta6(μ-Cl)12Cl2(OH2)4·4H2O is soluble in water, DMSO, and methanol. The solutions are an intense emerald green. UV–vis (water): 330, 400, 470 (sh), 638, 750 nm. Solid [Ta6(μ-Cl)12Cl2(OH2)4]·4H2O and its aqueous solutions are slowly oxidized by air to hexatantalum clusters with higher oxidation states. Stannous chloride is a convenient solution reductant, as it quickly reduces contaminant levels of [Ta6(μ-Cl)12(OH2)6]3+ and [Ta6(μ-Cl)12(OH2)6]4+ back to [Ta6(μ-Cl)12(OH2)6]2+.

B. Tetradecabromohexatantalum Octahydrate

Procedure

A vacuum-sealed ampule with TaBr5 (7.5 g, 12.9 mmol), Ga (0.80 g, 11.4 mmol), and KBr (2.39 g, 19.9 mmol) in the end reaction chamber is placed in the center of a 270°C preheated horizontal tube furnace and heated for 20 min. After being cooled to room temperature, the reactants/products are homogenized by gentle shaking, and this heating and homogenization cycle is repeated two times in order to disperse the molten gallium throughout the reaction mixture. The ampule is then placed in a tube furnace inclined to 45° and heated to 300°C over 1 h and held at that temperature for 12 h. The furnace is turned off and allowed to cool to room temperature. The ampule is removed from the furnace and the products are homogenized by vigorous shaking to give a dark green granular powder. The ampule is returned to the inclined furnace, heated to 400°C in 1 h, and held at that temperature for 24 h. The ampule is removed from the furnace, allowed to cool to room temperature, and opened in air. The dark solid is ground with a mortar and pestle to a dark green powder. The green powder is extracted by Soxhlet extraction with degassed water (170 mL) under argon for 24 h, as described above for Ta6(μ-Cl)12Cl2(OH2)4·4H2O. The resulting dark green solution is filtered through a medium-porosity fritted glass funnel in order to remove insoluble white GaO(OH) (as confirmed by powder X-ray diffractometry) powder. The dark green filtrate is treated with a filtered solution of SnBr2 (3.1 g) dissolved in 48% hydrobromic acid (200 mL) to convert any oxidized species to Ta6(μ-Br)12Br2(OH2)4·4H2O, as described above for Ta6(μ-Cl)12Cl2(OH2)4·4H2O. The mixture is cooled in an ice bath and filtered through a medium-porosity fritted glass funnel. The dark green solid is washed with 48% hydrobromic acid (30 mL) followed by diethyl ether (30 mL). Yield: 4.15 g (86%).

Anal. Calcd. for H8Br14O8Ta6: Ta, 46.23; Br, 47.63. Found: Ta, 46.8; Br, 48.22.

Properties

Ta6(μ-Br)12Br2(OH2)4·4H2O has solubility characteristics similar to the chloride analog. Solutions are an intense emerald green. UV–vis (water): 350, 420, 496 (sh), 638, 748 nm.

C. Tetrakis(Benzyltributylammonium) Octadecachlorohexatantalate

Procedure

The synthesis of this tetraalkylammonium salt of [Ta6(μ-Cl)12Cl6]4− is adapted from the method developed by McCarley17 for the synthesis of (NMe4)4[Nb6Cl18].4 In a glove box (a glove bag would be sufficient), Ta6(μ-Cl)12Cl2(OH2)4·4H2O (0.50 g, 0.29 mmol) is placed into a coarse porosity fritted glass Soxhlet thimble in a Soxhlet extractor. A condenser with gas inlet and small empty flask are added and the apparatus is attached to a Schlenk line. In a 100 mL Schlenk flask containing a stir bar, a solution of [N(CH2Ph)Bu3]Cl (0.36 g, 1.1 mmol) in 100% ethanol (50 mL) is degassed with argon with the help of a gas dispersion tube. The Soxhlet apparatus is joined to the Schlenk flask (with PTFE sleeves) under argon and the Ta6(μ-Cl)12Cl2(OH2)4·4H2O is extracted under argon into the stirring [N(CH2Ph)Bu3]Cl/ethanol solution for 1 h, resulting in a dark green solution. After the Soxhlet apparatus is detached, the ethanol is removed under vacuum at 30°C. Degassed benzene (70 mL) is added to the dark forest green solid by cannula. A Dean–Stark trap is attached to the Schlenk flask and the solid is dried by means of azeotropic distillation for ∼21 h under argon. The remaining benzene is then removed under vacuum. The dark forest green solid is dissolved in a minimum of cold (−40°C) CH2Cl2 in the glove box, and the resulting mixture is filtered through Celite® in order to remove a small amount of brown residue. The volume of the filtrate is reduced on a rotary evaporator until a small amount of brown residue forms. The solution is cooled to −40 °C and the brown solid is removed by filtration. The green filtrate is treated dropwise with toluene (∼25% of the solution volume) and the volume is reduced by rotary evaporation until a small amount of brown precipitate is noted. The solution is filtered and the volume reduced by rotary evaporation until a clear supernatant is observed over a green solid. The supernatant is decanted and the solid is washed with toluene (3 × 2 mL) and dried in vacuum. Yield: 0.72 g (88%).

Anal. Calcd. for C38H68N2Cl9Ta3: C, 32.26; H, 4.84; N, 1.98; Cl, 22.55. Found: C, 32.14; H, 5.04; N, 2.04; Cl, 22.14.

Properties

Green [N(CH2Ph)Bu3]4[Ta6(μ-Cl)12Cl6] is soluble in dichloromethane and 1,2-dichloroethane, but is insoluble in ether, benzene, and toluene. This tetraalkylammonium cation imparts higher solubility to the salt, compared to the NMe4+ salt, and the benzyl group reduces cation crystallographic disorder compared to NBu4+ salts. Single-crystal X-ray diffractometry on [N(CH2Ph)Bu3]4[Ta6(μ-Cl)12Cl6] showed a [Ta6(μ-Cl)12Cl6]4− core in each of two crystalline forms (one a solvate), with similar metrics to [Ta6(μ-Cl)12Cl6]4− salts with inorganic cations.15a

Acknowledgments

This research was supported in part with funds from the National Science Foundation (CHE-0078701), the National Cancer Institute (1 R21 RR14062-01), the Roy J. Carver Charitable Trust (grant 01-93), a pilot grant funded by NIH/NIDDK (P30 DK 54759) and the Cystic Fibrosis Foundation (ENGELH98S0), and the Department of Energy's Energy-Related Laboratory Equipment Program (tube furnace). The Siemens D5000 automated powder diffractometer and Nonius Kappa CCD diffractometer were purchased with support from the Roy J. Carver Charitable Trust (grants 96-36 and 00-192).

Notes

1.

Department of Chemistry, The University of Iowa, Iowa City, IA 52242.

2.

Department of Chemistry, Wake Forest University, Winston-Salem, NC 27109.

3.

The checkers recommend that a quick-fit be used here to simplify the procedure.

4.

The checkers report that the Me

4

N

+

salt of the Ta

6

Cl

18

4−

anion is easily prepared, without Soxhlet extraction, by simple addition of NMe

4

Cl to the Ta

6

Cl

18

4−

solution.

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2. Octahedral Hexamolybdenum Halide Clusters

Submitted by Chang-Tong Yang,1 Daniel N. T. Hay,1 and Louis Messerle1Checked by David J. Osborn III,2 Jeffrey N. Templeton,3 and Lisa F. Szczepura3

Molybdenum halides in lower oxidation states typically adopt dinuclear or polynuclear structures. One of the oldest known (1859) polynuclear clusters is Mo6X12,1 whose solid-state structure consists of octahedral Mo6 units bearing eight μ3-halides (inner chlorides), one over each of the eight octahedral faces, and six terminal (outer) halides in apical positions on the octahedral framework. Mo6Cl12, also known by its empirical formula MoCl2, has an extended structure in which some of the chlorine atoms are shared between clusters. Although it can be made by direct reduction of higher molybdenum halides, the product obtained is often impure. Much purer material can be obtained by addition of concentrated hydrochloric acid to the crude material, which affords discrete dianionic clusters of stoichiometry [Mo6(μ3-Cl)8Cl6]2−. The resulting chloromolybdic acid, (H3O)2[Mo6(μ3-Cl)8Cl6]·6H2O, is sparingly soluble in water and can be recrystallized from hydrochloric acid. This material can be converted in near-quantitative yield to pure Mo6Cl12 by thermolysis in vacuum.2

Mo6Cl12, its discrete halide and chalcogenide derivatives, and its coordination complexes3 have attracted considerable attention because of their interesting photochemical properties/lifetimes (phosphorescence, luminescence, and electrogenerated chemiluminescence),4 utility in catalysis,5 radiochemistry,6 sensor and conductor research,7 intercalation chemistry,8