TY - JOUR
T1 - Syntheses and structures of silicon analogues of cyclopropabenzenes
AU - Tajima, Tomoyuki
AU - Hatano, Ken
AU - Sasaki, Takayo
AU - Sasamori, Takahiro
AU - Takeda, Nobuhiro
AU - Tokitoh, Norihiro
AU - Takagi, Nozomi
AU - Nagase, Shigeru
N1 - Funding Information:
This work was supported by Grants-in-Aid for COE Research on Elements Science (No. 12CE2005), 21st Century COE on Kyoto University Alliance for Chemistry, and Scientific Research on Priority Areas (A) (Nos. 09239208 and 11166250) from Ministry of Education, Culture, Sports, Science, and Technology of Japan. We thank Professor R. Neidlein (Pharmazeutisch-Chemischen Institut der Universität Heidelberg) for providing information of cyclopropabenzene prior to publication. Central Glass Co. Ltds. is also acknowledged for a gift of tetrafluorosilane. Computation time was provided by the Supercomputer Laboratory, Institute for Chemical Research, Kyoto University.
PY - 2003/12/1
Y1 - 2003/12/1
N2 - The reactions of an overcrowded diaryldilithiosilane, Tbt(Dip)SiLi 2 (Tbt=2,4,6-tris[bis(trimethylsilyl)methyl]phenyl; Dip=2,6-diisopropylphenyl), with o-dibromobenzene and 1,2,4, 5-tetrabromobenzene resulted in the synthesis and isolation of the first stable silacyclopropabenzene and bis(silacyclopropa)benzenes (IUPAC name is 4,8-disilatricyclo[5.1.0.03,5]octa-1,3(5), 6-triene), respectively. The crystallographic analyses and theoretical calculations revealed that the lengths of the juncture carbon-carbon bonds of the mono- and bis(silacyclopropa)benzenes were marginally in the range of carbon-carbon bond lengths of usual benzene rings. It is shown that this structural feature is attributable to a decrease in the strain energy of silacyclopropabenzenes relative to the corresponding cyclopropabenzenes, and the strain energy is a simple additive function of the number of the fused three-membered rings involving Si atom.
AB - The reactions of an overcrowded diaryldilithiosilane, Tbt(Dip)SiLi 2 (Tbt=2,4,6-tris[bis(trimethylsilyl)methyl]phenyl; Dip=2,6-diisopropylphenyl), with o-dibromobenzene and 1,2,4, 5-tetrabromobenzene resulted in the synthesis and isolation of the first stable silacyclopropabenzene and bis(silacyclopropa)benzenes (IUPAC name is 4,8-disilatricyclo[5.1.0.03,5]octa-1,3(5), 6-triene), respectively. The crystallographic analyses and theoretical calculations revealed that the lengths of the juncture carbon-carbon bonds of the mono- and bis(silacyclopropa)benzenes were marginally in the range of carbon-carbon bond lengths of usual benzene rings. It is shown that this structural feature is attributable to a decrease in the strain energy of silacyclopropabenzenes relative to the corresponding cyclopropabenzenes, and the strain energy is a simple additive function of the number of the fused three-membered rings involving Si atom.
KW - Bis(silacyclopropa)benzenes
KW - Crystallographic structural analysis
KW - Diaryldilithiosilane
KW - Silacyclopropabenzene
KW - Three-membered ring
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U2 - 10.1016/S0022-328X(03)00446-7
DO - 10.1016/S0022-328X(03)00446-7
M3 - Article
AN - SCOPUS:0142025005
VL - 686
SP - 118
EP - 126
JO - Journal of Organometallic Chemistry
JF - Journal of Organometallic Chemistry
SN - 0022-328X
IS - 1-2
ER -