摘要
精确测定了1—甲基杂氮硅三环的X光晶体结构,并用量子化学SCC—DV—X_a法对杂氮硅三环类化合物RSi(OCH_2CH_2)_3N(R=CH_3,F,Cl,Br,I)中硅氮成键本质进行了研究。计算结果证明硅氮间形成的配键中除σ键外还存在微弱的π键,硅原子的3d轨道在成键中起一定的作用。 晶体学参数:C_7H_(15)NO_3Si,M_r=189.3,单斜晶系,空间群P2_1/n,a=7.606(1),b=12.150(1),c=9.779(1),β=91.64(1)°,V=903.4,Z=4,D_c=1.392gcm^(-3),F(000)=408,μ(MoK_a)=2.208cm^(-1)。1510个可观察衍射参与最小二乘修正,最终偏离因子R=0.044。
As part of our investigations on bioactive small molecules, the crystal structure of 1-methylsi-latrane was redetermined in order to provide more reliable geometry fot quantum chemistry calcu-latons. The crystal is monoclinic. P21/n, a = 7. 606(1), b=12.150(1), c=9. 779(1) A,β= 91.64(1)°, V = 903. 4A3, Z=4, Dc= 1. 392gcm-3, F(000) = 408,μ(MoKa) = 2. 208cm-1, R = 0. 044 for 1510 observed reflections. The redetermination, resulting in bond distances and angles with e. s. d' s of 0. 002 - 0. 004A and 0. 1 - 0. 2° respectively, confirmed the quasi C3 point group symmetry of the molecule. The study of the nature of Si - N bonding in silatranes.RSi(OCH2CH2)3N (R=CH3,F,Cl,Br,I) with SCC-DV-Xa method was carrted out, and the feature of Si-N bonding was discussed in detail.
