skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Synthesis of main group, rare-earth, and d{sup 0} metal complexes containing beta-hydrogen

Abstract

A series of organometallic compounds containing the tris(dimethylsilyl)methyl ligand are described. The potassium carbanions KC(SiHMe 2) 3 and KC(SiHMe 2}) 3TMEDA are synthesized by deprotonation of the hydrocarbon HC(SiHMe 2) 3 with potassium benzyl. KC(SiHMe 2) 3TMEDA crystallizes as a dimer with two types of three-center-two-electron KH- Si interactions. Homoleptic Ln(III) tris(silylalkyl) complexes containing β-SiH groups M{C(SiHMe 2) 3} 3 (Ln = Y, Lu, La) are synthesized from salt elimination of the corresponding lanthanide halide and 3 equiv. of KC(SiHMe 2) 3. The related reactions with Sc yield bis(silylalkyl) ate-complexes containing either LiCl or KCl. The divalent calcium and ytterbium compounds M{C(SiHMe 2) 3} 2L (M = Ca, Yb; L = THF 2 or TMEDA) are prepared from MI 2 and 2 equiv of KC(SiHMe 2) 3. The compounds M{C(SiHMe 2) 3} 2L (M = Ca, Yb; L = THF 2 or TMEDA) and La{C(SiHMe 2) 3} 3 react with 1 equiv of B(C 6F 5) 3 to give 1,3- disilacyclobutane {Me2Si-C(SiHMe2)2}2 and MC(SiHMe2)3HB(C6F5)3L, and La{C(SiHMe 2) 3} 2HB(C 6F 5) 3, respectively. The corresponding reactions of Ln{C(SiHMe 2) 3} 3 (Ln = Y, Lu) give the β-SiH abstraction product [{(Me 2HSi) 3C} 2LnC(SiHMe 2) 2SiMe 2][HB(C 6F 5) 3]more » (Ln = Y, Lu), but the silene remains associated with the Y or Lu center. The abstraction reactions of M{C(SiHMe 2) 3} 2L (M = Ca, Yb; L = THF 2or TMEDA) and Ln{C(SiHMe 2) 3} 3 (Ln = Y, Lu, La) and 2 equiv of B(C 6F 5) 3 give the expected dicationic M{HB(C 6F 5) 3} 2L (M = Ca, Yb; L = THF 2 or TMEDA) and dicationic mono(silylalkyl) LnC(SiHMe 2) 3{HB(C 6F 5) 3} 2 (Ln = Y, Lu, La), respectively. Salt metathesis reactions of Cp 2(NR 2)ZrX (X = Cl, I, OTf; R = t-Bu, SiHMe 2) and lithium hydrosilazide ultimately afford hydride products Cp 2(NR 2)ZrH that suggest unusual β-hydrogen elimination processes. A likely intermediate in one of these reactions, Cp 2Zr[N(SiHMe 2)t-Bu][N(SiHMe 2) 2], is isolated under controlled synthetic conditions. Addition of alkali metal salts to this zirconium hydrosilazide compound produces the corresponding zirconium hydride. However as conditions are varied, a number of other pathways are also accessible, including C-H/Si-H dehydrocoupling, γ-abstraction of a CH, and β-abstraction of a SiH. Our observations suggest that the conversion of (hydrosilazido)zirconocene to zirconium hydride does not follow the classical four-center β- elimination mechanism.« less

Authors:
 [1]
  1. Iowa State Univ., Ames, IA (United States)
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1082979
Report Number(s):
IS-T 3091
DOE Contract Number:  
AC02-07CH11358
Resource Type:
Thesis/Dissertation
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Yan, Ka King. Synthesis of main group, rare-earth, and d{sup 0} metal complexes containing beta-hydrogen. United States: N. p., 2013. Web. doi:10.2172/1082979.
Yan, Ka King. Synthesis of main group, rare-earth, and d{sup 0} metal complexes containing beta-hydrogen. United States. doi:10.2172/1082979.
Yan, Ka King. Tue . "Synthesis of main group, rare-earth, and d{sup 0} metal complexes containing beta-hydrogen". United States. doi:10.2172/1082979. https://www.osti.gov/servlets/purl/1082979.
@article{osti_1082979,
title = {Synthesis of main group, rare-earth, and d{sup 0} metal complexes containing beta-hydrogen},
author = {Yan, Ka King},
abstractNote = {A series of organometallic compounds containing the tris(dimethylsilyl)methyl ligand are described. The potassium carbanions KC(SiHMe2)3 and KC(SiHMe2})3TMEDA are synthesized by deprotonation of the hydrocarbon HC(SiHMe2)3 with potassium benzyl. KC(SiHMe2)3TMEDA crystallizes as a dimer with two types of three-center-two-electron KH- Si interactions. Homoleptic Ln(III) tris(silylalkyl) complexes containing β-SiH groups M{C(SiHMe2)3}3 (Ln = Y, Lu, La) are synthesized from salt elimination of the corresponding lanthanide halide and 3 equiv. of KC(SiHMe2)3. The related reactions with Sc yield bis(silylalkyl) ate-complexes containing either LiCl or KCl. The divalent calcium and ytterbium compounds M{C(SiHMe2)3}2L (M = Ca, Yb; L = THF2 or TMEDA) are prepared from MI2 and 2 equiv of KC(SiHMe2)3. The compounds M{C(SiHMe2)3}2L (M = Ca, Yb; L = THF2 or TMEDA) and La{C(SiHMe2)3}3 react with 1 equiv of B(C6F5)3 to give 1,3- disilacyclobutane {Me2Si-C(SiHMe2)2}2 and MC(SiHMe2)3HB(C6F5)3L, and La{C(SiHMe2)3}2HB(C6F5)3, respectively. The corresponding reactions of Ln{C(SiHMe2)3}3 (Ln = Y, Lu) give the β-SiH abstraction product [{(Me2HSi)3C}2LnC(SiHMe2)2SiMe2][HB(C6F5)3] (Ln = Y, Lu), but the silene remains associated with the Y or Lu center. The abstraction reactions of M{C(SiHMe2)3}2L (M = Ca, Yb; L = THF2or TMEDA) and Ln{C(SiHMe2)3}3 (Ln = Y, Lu, La) and 2 equiv of B(C6F5)3 give the expected dicationic M{HB(C6F5)3}2L (M = Ca, Yb; L = THF2 or TMEDA) and dicationic mono(silylalkyl) LnC(SiHMe2)3{HB(C6F5)3}2 (Ln = Y, Lu, La), respectively. Salt metathesis reactions of Cp2(NR2)ZrX (X = Cl, I, OTf; R = t-Bu, SiHMe2) and lithium hydrosilazide ultimately afford hydride products Cp2(NR2)ZrH that suggest unusual β-hydrogen elimination processes. A likely intermediate in one of these reactions, Cp2Zr[N(SiHMe2)t-Bu][N(SiHMe2)2], is isolated under controlled synthetic conditions. Addition of alkali metal salts to this zirconium hydrosilazide compound produces the corresponding zirconium hydride. However as conditions are varied, a number of other pathways are also accessible, including C-H/Si-H dehydrocoupling, γ-abstraction of a CH, and β-abstraction of a SiH. Our observations suggest that the conversion of (hydrosilazido)zirconocene to zirconium hydride does not follow the classical four-center β- elimination mechanism.},
doi = {10.2172/1082979},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2013},
month = {1}
}

Thesis/Dissertation:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this thesis or dissertation.

Save / Share: