2,3—二氢—5,6—二苯基吡嗪及其2∶1硝酸银配合物的合成与晶体结构

合成了配体2,3-二氢-5,6-二苯基吡嗪(C_(16)H_(14)N_2)及其硝酸银配合物AgNO_3(C_(16)H_(14)N_2)_2, 并用CAD4衍射仪测定了它们的晶体结构。晶体学数据为, 配体C_(16)H_(14)N_2: 单斜晶系, 空间群P2_1/n, a=0.5685(3),b=0.7928(1), c=2.7261(8) nm, β=95.02(6)°, V=1.2287 nm, z=4,D_c=1.27gcm~(-3),μ=0.81cm~(-1),R=0.031, R_w=0.033; 配合物AgNO3(C_(16)H_(14)N_2)_2:单斜晶系, 空间群A2, a=0.5655(3), b=0.7771(2), c=3.0.502(5) nm, β=94.90(2)°, V=1.3355 nm, z=2, D_c=1.59gcm~(-3),μ=7.87cm~(-1), R=0.033, R_2=0.028。测定结果表明, 在C_(16)H_(14)N_2分子中, 有关键长、键角均符合相应正常值。在AgNO3(C_(16)H_(14)N_2)_2晶体中NO_3~-为双齿配体; C_(16)H_(14)N_2则因吡嗪环上苯基的空间障碍而作为单齿配体出现; Ag原子处于二重轴上, 周围由四个氧和两个氮原子组成严重扭曲的配位八面体; Ag(1)—O(1)键长为2.828, Ag(1)—O(2)为2.520, Ag(1)—N(31)为0.2399 nm. Ag的配位八面体间借公用相对两个顶点氧原子而构成无限链状结构.

THE CRYSTAL AND MOLECULAR STRUCTURES OF 2,3-DIHYDRO-5,6-DIPHENYLPYRAZINE AND ITS COMPLEX WITH SILVER NITRATE

The crystal and molecular structures of 2,3-dihydro-5,6-dipenylpyrazine (C_(16)H_(14)N_2) and its complex with silver nitrate AgNO_3(C_(16)H_(14)N_2)_2 were determined by CAD4 single crystal diffractometer, using graphite monochromated Mo-Kα radiation. The crystallographic data are: (1) C_(16)H_(14)N_2, monoclinic, P2_1/n, α=0.5685(3), b=0.7928(1), c=2.7261(8) nm, β=95.02(6)°, V=1.2287 nm, z=4. (2) AgNO_3 (C_(16)H_(14)N_2)_2, monoclinic, A_2, α=0.5655(3), b=0.7791(2), c=3.0502(5) nm, β=94.90(2)°, V=1.3355 nm, z=2.The structure of (1) was solved by direct method and (2) by heavy atom method. The full matrix least squares refinement for (1) with isotripic thermal parameters for H atoms and anisotropic for the others was converged at R=0.031, and R_W=0.033, the refinement for (2), excluding H atoms, at R=0.033 and R_W=0.028. In the structure of C_(16)H_(14)N_2, bond lengths and angles are not unexpected, and dihedral angles between pyrazine ring plane and each plane of the two phenyls are 151.9° and 136.7° respectively. In the structure of AgNO_3 (C_(16)H_(14)N_2)_2, the Ag atom is positioned on a 2-fold axis, and coordinated by two N and four O atons to form a severely distorted octahedron, the distance Ag(1)—O(1) is 2.828, Ag(1)—O(2) 2.520, and Ag(1)—N(31) 0.2399 nm. The conformation of the C_(16)H_(14)N_2 molecule in the complex was compared with that of the free ligand.