Crystal Structures of 2-Bromo-1,1,1,3,3,3-Hexa­methyl-2-(Tri­methyl­sil­yl)Tris­ilane and 2-Bromo-1,1,1,3,3,3-Hexa­isopropyl-2-(Triiso­propyl­sil­yl)Tri­silane

Eva M. Gulotty; Richard J. Staples; Shannon M. Biros; Peter P. Gaspar; Nigam P. Rath; William R. Winchester

doi:10.1107/s2056989018009696

Crystal Structures of 2-Bromo-1,1,1,3,3,3-Hexamethyl-2-(Trimethylsilyl)Trisilane and 2-Bromo-1,1,1,3,3,3-Hexaisopropyl-2-(Triisopropylsilyl)Trisilane

Eva M. Gulotty, Richard J. Staples, Shannon M. Biros, Peter P. Gaspar, Nigam P. Rath, William R. Winchester

University of Missouri-St. Louis

Research output: Contribution to journal › Article › peer-review

Abstract

<div class="line" id="line-11"> The synthesis and crystal structures of two tris(trialkylsilyl)silyl bromide compounds, C9H27BrSi4 (I, HypSiBr) and C27H63BrSi4 (II, TipSiBr), are described. Compound I was prepared in 85% yield by free-radical bromination of 1,1,1,3,3,3-hexamethyl-2-(trimethylsilyl)trisilane using bromobutane and 2,2′-azobis(2-methylpropionitrile) as a radical initiator at 333&emsp14;K. The molecule possesses threefold rotational symmetry, with the central Si atom and the Br atom being located on the threefold rotation axis. The Si—Br bond distance is 2.2990&emsp14;(12)&emsp14;Å and the Si—Si bond lengths are 2.3477&emsp14;(8)&emsp14;Å. The Br—Si—Si bond angles are 104.83&emsp14;(3)° and the Si—Si—Si bond angles are 113.69&emsp14;(2)°, reflecting the steric hindrance inherent in the three trimethylsilyl groups attached to the central Si atom. Compound II was prepared in 55% yield by free-radical bromination of 1,1,1,3,3,3-hexaisopropyl-2-(triisopropylsilyl)trisilane using N-bromosuccinimide and 2,2′-azobis(2-methylpropionitrile) as a radical initiator at 353&emsp14;K. Here the Si—Br bond length is 2.3185&emsp14;(7)&emsp14;Å and the Si—Si bond lengths range from 2.443&emsp14;(1) to 2.4628&emsp14;(9)&emsp14;Å. The Br—Si—Si bond angles range from 98.44&emsp14;(3) to 103.77&emsp14;(3)°, indicating steric hindrance between the three triisopropylsilyl groups.</div>

Original language	American English
Journal	Acta Crystallographica Section E: Crystallographic Communications
Volume	74
DOIs	https://doi.org/10.1107/s2056989018009696
State	Published - Aug 1 2018

Keywords

HypSiBr
TipSiBr
crystal structure
intramolecular C-H⋯Br hydrogen bonding
steric hindrance
supersilyl bromide

Disciplines

Inorganic Chemistry
Chemistry
Biochemistry, Biophysics, and Structural Biology

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Cite this

Gulotty, E. M., Staples, R. J., Biros, S. M., Gaspar, P. P., Rath, N. P., & Winchester, W. R. (2018). Crystal Structures of 2-Bromo-1,1,1,3,3,3-Hexamethyl-2-(Trimethylsilyl)Trisilane and 2-Bromo-1,1,1,3,3,3-Hexaisopropyl-2-(Triisopropylsilyl)Trisilane. Acta Crystallographica Section E: Crystallographic Communications, 74. https://doi.org/10.1107/s2056989018009696

Crystal Structures of 2-Bromo-1,1,1,3,3,3-Hexamethyl-2-(Trimethylsilyl)Trisilane and 2-Bromo-1,1,1,3,3,3-Hexaisopropyl-2-(Triisopropylsilyl)Trisilane. / Gulotty, Eva M.; Staples, Richard J.; Biros, Shannon M. et al.
In: Acta Crystallographica Section E: Crystallographic Communications, Vol. 74, 01.08.2018.

Research output: Contribution to journal › Article › peer-review

Gulotty, EM, Staples, RJ, Biros, SM, Gaspar, PP, Rath, NP & Winchester, WR 2018, 'Crystal Structures of 2-Bromo-1,1,1,3,3,3-Hexamethyl-2-(Trimethylsilyl)Trisilane and 2-Bromo-1,1,1,3,3,3-Hexaisopropyl-2-(Triisopropylsilyl)Trisilane', Acta Crystallographica Section E: Crystallographic Communications, vol. 74. https://doi.org/10.1107/s2056989018009696

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title = "Crystal Structures of 2-Bromo-1,1,1,3,3,3-Hexamethyl-2-(Trimethylsilyl)Trisilane and 2-Bromo-1,1,1,3,3,3-Hexaisopropyl-2-(Triisopropylsilyl)Trisilane",

abstract = " The synthesis and crystal structures of two tris(trialkylsilyl)silyl bromide compounds, C9H27BrSi4 (I, HypSiBr) and C27H63BrSi4 (II, TipSiBr), are described. Compound I was prepared in 85% yield by free-radical bromination of 1,1,1,3,3,3-hexamethyl-2-(trimethylsilyl)trisilane using bromobutane and 2,2′-azobis(2-methylpropionitrile) as a radical initiator at 333&emsp14;K. The molecule possesses threefold rotational symmetry, with the central Si atom and the Br atom being located on the threefold rotation axis. The Si—Br bond distance is 2.2990&emsp14;(12)&emsp14;Å and the Si—Si bond lengths are 2.3477&emsp14;(8)&emsp14;Å. The Br—Si—Si bond angles are 104.83&emsp14;(3)° and the Si—Si—Si bond angles are 113.69&emsp14;(2)°, reflecting the steric hindrance inherent in the three trimethylsilyl groups attached to the central Si atom. Compound II was prepared in 55% yield by free-radical bromination of 1,1,1,3,3,3-hexaisopropyl-2-(triisopropylsilyl)trisilane using N-bromosuccinimide and 2,2′-azobis(2-methylpropionitrile) as a radical initiator at 353&emsp14;K. Here the Si—Br bond length is 2.3185&emsp14;(7)&emsp14;Å and the Si—Si bond lengths range from 2.443&emsp14;(1) to 2.4628&emsp14;(9)&emsp14;Å. The Br—Si—Si bond angles range from 98.44&emsp14;(3) to 103.77&emsp14;(3)°, indicating steric hindrance between the three triisopropylsilyl groups.",

keywords = "HypSiBr, TipSiBr, crystal structure, intramolecular C-H⋯Br hydrogen bonding, steric hindrance, supersilyl bromide",

author = "Gulotty, {Eva M.} and Staples, {Richard J.} and Biros, {Shannon M.} and Gaspar, {Peter P.} and Rath, {Nigam P.} and Winchester, {William R.}",

year = "2018",

month = aug,

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doi = "10.1107/s2056989018009696",

language = "American English",

volume = "74",

journal = "Acta Crystallographica Section E: Crystallographic Communications",

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TY - JOUR

T1 - Crystal Structures of 2-Bromo-1,1,1,3,3,3-Hexamethyl-2-(Trimethylsilyl)Trisilane and 2-Bromo-1,1,1,3,3,3-Hexaisopropyl-2-(Triisopropylsilyl)Trisilane

AU - Gulotty, Eva M.

AU - Staples, Richard J.

AU - Biros, Shannon M.

AU - Gaspar, Peter P.

AU - Rath, Nigam P.

AU - Winchester, William R.

PY - 2018/8/1

Y1 - 2018/8/1

N2 - The synthesis and crystal structures of two tris(trialkylsilyl)silyl bromide compounds, C9H27BrSi4 (I, HypSiBr) and C27H63BrSi4 (II, TipSiBr), are described. Compound I was prepared in 85% yield by free-radical bromination of 1,1,1,3,3,3-hexamethyl-2-(trimethylsilyl)trisilane using bromobutane and 2,2′-azobis(2-methylpropionitrile) as a radical initiator at 333&emsp14;K. The molecule possesses threefold rotational symmetry, with the central Si atom and the Br atom being located on the threefold rotation axis. The Si—Br bond distance is 2.2990&emsp14;(12)&emsp14;Å and the Si—Si bond lengths are 2.3477&emsp14;(8)&emsp14;Å. The Br—Si—Si bond angles are 104.83&emsp14;(3)° and the Si—Si—Si bond angles are 113.69&emsp14;(2)°, reflecting the steric hindrance inherent in the three trimethylsilyl groups attached to the central Si atom. Compound II was prepared in 55% yield by free-radical bromination of 1,1,1,3,3,3-hexaisopropyl-2-(triisopropylsilyl)trisilane using N-bromosuccinimide and 2,2′-azobis(2-methylpropionitrile) as a radical initiator at 353&emsp14;K. Here the Si—Br bond length is 2.3185&emsp14;(7)&emsp14;Å and the Si—Si bond lengths range from 2.443&emsp14;(1) to 2.4628&emsp14;(9)&emsp14;Å. The Br—Si—Si bond angles range from 98.44&emsp14;(3) to 103.77&emsp14;(3)°, indicating steric hindrance between the three triisopropylsilyl groups.

AB - The synthesis and crystal structures of two tris(trialkylsilyl)silyl bromide compounds, C9H27BrSi4 (I, HypSiBr) and C27H63BrSi4 (II, TipSiBr), are described. Compound I was prepared in 85% yield by free-radical bromination of 1,1,1,3,3,3-hexamethyl-2-(trimethylsilyl)trisilane using bromobutane and 2,2′-azobis(2-methylpropionitrile) as a radical initiator at 333&emsp14;K. The molecule possesses threefold rotational symmetry, with the central Si atom and the Br atom being located on the threefold rotation axis. The Si—Br bond distance is 2.2990&emsp14;(12)&emsp14;Å and the Si—Si bond lengths are 2.3477&emsp14;(8)&emsp14;Å. The Br—Si—Si bond angles are 104.83&emsp14;(3)° and the Si—Si—Si bond angles are 113.69&emsp14;(2)°, reflecting the steric hindrance inherent in the three trimethylsilyl groups attached to the central Si atom. Compound II was prepared in 55% yield by free-radical bromination of 1,1,1,3,3,3-hexaisopropyl-2-(triisopropylsilyl)trisilane using N-bromosuccinimide and 2,2′-azobis(2-methylpropionitrile) as a radical initiator at 353&emsp14;K. Here the Si—Br bond length is 2.3185&emsp14;(7)&emsp14;Å and the Si—Si bond lengths range from 2.443&emsp14;(1) to 2.4628&emsp14;(9)&emsp14;Å. The Br—Si—Si bond angles range from 98.44&emsp14;(3) to 103.77&emsp14;(3)°, indicating steric hindrance between the three triisopropylsilyl groups.

KW - HypSiBr

KW - TipSiBr

KW - crystal structure

KW - intramolecular C-H⋯Br hydrogen bonding

KW - steric hindrance

KW - supersilyl bromide

U2 - 10.1107/s2056989018009696

DO - 10.1107/s2056989018009696

M3 - Article

VL - 74

JO - Acta Crystallographica Section E: Crystallographic Communications

JF - Acta Crystallographica Section E: Crystallographic Communications

ER -