顺式-二氯-1,3-环戊二胺合铂的晶体结构和振动光谱的简正坐标分析

测定了顺式一二氯-1,3-环戊二胺合铂,cis-Pt(DACP)C1_2]的晶体结构和分子结构,晶体属单斜晶系,空间群为C2/c,a=13.222(3),b=10.697(1),c=13.486(5)°A,β=116.06(2)°,Z=8。利用Patterson法得到Pt原子位置,经差值Fourier合成找到其余非氢原子的位置,用全矩阵最小二乘法修正,最后R因子为0.029。同时进行了cis-Pt(DACP)C1_2]的振动光谱简正坐标分析,定义了80个内坐标,得到60个频率计算值,与观测值的最大误差为15cm~(-1)。采用U-B力场定义了56个力常数,得到合理的优化结果。根据位能分布进行了各振动频率的归属,並讨论了简正坐标分析中内坐标与力场的关系。

CRYSATL STRUCTURE ND NORM L COORDINATE ANALYSIS OF cis -DICHLORO-1,3-CYCLOPENTA-DIAMINEPLATINUM(Ⅱ)

The crystal of cis-dichloro-1, 3-cyclopentadiamineplatinum, cis-Pt(DACP)-Cl2] belongs to monoclinic system with space group C2/c, a = 13.222 (3), b = 10.697(1),c = 13.486(5)A,β=116.06(2)°,Z=8. The positional parameters of Pt atom were derived from Patterson function and the parameters of the other non-hydrogen atoms were solved by difference Fourier syntheses. The full matrix least squares refinement for all atoms gave a final discrepancy factor R = 0.029. According to the molecular structure, 80 internal coordinates were established and 60 theoretical vibrational frequencies were calculated. The average difference between the calculated frequencies and observed ones is 4.4cm-1 or 0.79%. 56 force constants defined by U-B force field were refined and the values were reasonable. The frequencies were assigned for cis-Tt(DACP)Cl2] in terms of potential energy distributions among force constants. The relationship between internal coordinate and force field is discussed.