The Crystal Structure of Bicyclopropyl.

Synthesis of a tert-butyl substituted bis(silirane) and comparison with its methyl and phenyl analogs

“…The central Si1eSi1 i bond length is 2.310(5) Å, slightly shorter than a typical SieSi bond length of 2.33 Å [18]. This shorter bond length is similar to the observation made for 1,1 0 -bi(cyclopropane) [19]. The SieC bond distances of the silirane ring are all slightly longer than normal: Si1eC1, Si1eC2, 1.88(1) Å; compared to 1.87 Å in unstrained silicon systems [20].…”

Three-Membered-Ring-Based Molecular Architectures

“…17 The central bond in 1 was found to be significantly shorter than both types of the cyclopropane bonds ( Figure 1). 17 In a second gas-phase electron diffraction (GED) study of bicyclopropyl (1), 18 the conformer distribution was 47.5% s-trans and 52.5% gauche ( ) 48.7°) corresponding to an energy difference of less than 500 cal/mol in favor of the s-trans conformer. 18 Since conformer distributions cannot very accurately be determined by the GED method, the energy difference between the two conformers as determined for the liquid phase by Lüttke et al is significantly more reliable.…”

The crystal structure of 2,3,6,7,7,8-hexamethyl-1,5-diphenyltetracyclo[3,3,0,02,8,03,6]octan-4-one

“…The exocyclic bond lengths and angles are expected to be shorter and larger, respectively, than the normal values, characteristic of bent bonding. The average exocyclic C-C bond length, 1.524 (9) A, compares to 1-487 A in bicyclopropane (Eraker & Romming, 1967) and 1.478 (5) A in a pentacyclic compound (Hwang, Donohue & Tsai, 1972). The average exocyclic angle is 123.4 (6) °, much greater than the predicted 116 ° (Lukina, 1962).…”