TY - JOUR
T1 - Highly asymmetric coordination in alkenes
T2 - Gas-phase structures of trans-1,2-dichloro-1,2-disilylethene and 1-bromo-1-silylethene
AU - McLachlan, Lorna J.
AU - Hinchley, Sarah L.
AU - Rankin, David W.H.
AU - Morrison, Carole A.
AU - Robertson, Heather E.
AU - Mitzel, Norbert W.
AU - RUdinger, Christoph
AU - Schmidbaur, Hubert
PY - 2003/10/6
Y1 - 2003/10/6
N2 - The molecular structures of trans-1,2-dichloro-1,2-disilylethene and 1-bromo-1-silylethene have been determined by gas-phase electron diffraction (GED) and ab initio molecular orbital calculations (MP2/6-311G*). Both compounds were found to have highly asymmetric coordination around the carbon atoms with [ab initio (re)/GED (ra)] C=C-Cl [117.0/117.0(2)°] and C=C-Si [126.2/128.1(1)°] in the C2h structure of trans-1,2-dichloro-1,2-disilylethene and C=C-Br [119.2/120.7(4)°] and C=C-Si [125.0/125.0(4)°] in the Cs structure of 1-bromo-1-silylethene. Other important structural parameters for trans-1,2-dichloro-1,2-disilylethene are C=C [135.2/134.5(3) pm], C-Si [189.4/ 187.9(2) pm], and C-Cl [175.1/174.9(1) pm], and C=C [134.2/133.4(2) pm], C-Si [187.8/187.2(3) pm], and C-Br [191.3/191.0(3) pm] for 1-bromo-1-silylethene. Further ab initio calculations were carried out on CH2CRX and trans-(CRX)2 (R = SiH3, CH3, or H; X = H, F, Cl, or Br) to gauge the effects of electron-withdrawing and electron-donating groups on the structures. They reveal some even more distorted structures. The asymmetric appearance of these molecules can largely be accounted for by valence shell electron pair repulsion theory.
AB - The molecular structures of trans-1,2-dichloro-1,2-disilylethene and 1-bromo-1-silylethene have been determined by gas-phase electron diffraction (GED) and ab initio molecular orbital calculations (MP2/6-311G*). Both compounds were found to have highly asymmetric coordination around the carbon atoms with [ab initio (re)/GED (ra)] C=C-Cl [117.0/117.0(2)°] and C=C-Si [126.2/128.1(1)°] in the C2h structure of trans-1,2-dichloro-1,2-disilylethene and C=C-Br [119.2/120.7(4)°] and C=C-Si [125.0/125.0(4)°] in the Cs structure of 1-bromo-1-silylethene. Other important structural parameters for trans-1,2-dichloro-1,2-disilylethene are C=C [135.2/134.5(3) pm], C-Si [189.4/ 187.9(2) pm], and C-Cl [175.1/174.9(1) pm], and C=C [134.2/133.4(2) pm], C-Si [187.8/187.2(3) pm], and C-Br [191.3/191.0(3) pm] for 1-bromo-1-silylethene. Further ab initio calculations were carried out on CH2CRX and trans-(CRX)2 (R = SiH3, CH3, or H; X = H, F, Cl, or Br) to gauge the effects of electron-withdrawing and electron-donating groups on the structures. They reveal some even more distorted structures. The asymmetric appearance of these molecules can largely be accounted for by valence shell electron pair repulsion theory.
UR - http://www.scopus.com/inward/record.url?scp=0141566472&partnerID=8YFLogxK
U2 - 10.1021/ic034596d
DO - 10.1021/ic034596d
M3 - Article
AN - SCOPUS:0141566472
SN - 0020-1669
VL - 42
SP - 6539
EP - 6544
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 20
ER -