cyclo-stannasiloxanes cyclo-[t-Bu(OH)Si(OSnt-Bu2O)2Si(OH)t-Bu] (1) and cyclo-t-Bu2Si[OSn(CH2SiMe3)2O]2Sit-Bu2} (2) as well as the synthesis of the six-membered cyclo-stannasiloxane cyclo-t-Bu2Si[OSn(CH2SiMe3)2]2O} (3) are reported. Compound 1 crystallizes as its trans isomer, but the cis isomer dominates in solution. In agreement with the experimentally obtained results, ab initio and DFT calculations on the model
八元的合成和晶体结构环-stannasiloxanes环[ -吨-Bu(OH)的Si(OSN吨-Bu 2 O)2的Si(OH)吨-Bu](1)和环- 吨-Bu 2的Si [OSN(CH 2森达3)2 O] 2的Si吨-Bu 2 }(2),以及所述六元的合成环-stannasiloxane环- 吨-Bu 2的Si [OSN(CH报告了2 SiMe 3)2 ] 2 O}(3)。化合物1以其反式异构体形式结晶,但顺式异构体在溶液中占主导地位。与实验获得的结果一致,对模型化合物环-(H 2 SiO)4(4),环-[H 2 Si(OSnH 2)OSiH 2 ](5),环-O( H 2 SiOSnH 2)2 O(6)和环-[H 2 Si(OSiH 2)OSnH 2 ](7)表示采用褶皱结构的能量偏好随着环中
锡原子数量的增加而增加,并且环的柔韧性降低。褶皱构象的丰富多样性归因于不同有机取代基的空间需求。