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本文报道起始模型对于X射线实验观测量和已知立体化学观测量作约束参数最小二乘修正的结果.经修正和扩展的模型,不仅包括DPI分子的全部非氢原子和一个镉原子,而且还加进49个水分子.由反常散射和模型信息概率相联合得到相角,各项系数按相角可靠性加权,其2F_o-F_c Fourier综合给出清晰的结果,无明显的对试用模型的偏向.最后得到的模型有合理的立体化学,同理想键长的均方根偏离是0.027A;同观测X射线散射相当吻合,对 10—2.4A分辨率的全部数据其偏离因子R=0.182.
This paper reports the results of the initial model for X-ray experimental observations and known stereochemical observations as the least-squares modification of the constraint parameters.The modified and extended model includes not only all non-hydrogen atoms and one cadmium atom of DPI molecules, but also 49 water molecules were added, and the phase angle was obtained by the combination of the anomalous scattering and the model information probabilities. The coefficients were weighted according to the phase angle reliability, and the 2F_o-F_c Fourier synthesis gave a clear result. The resulting model has a reasonable stereochemistry and the mean square root deviation from the ideal bond length is 0.027A, which is in good agreement with the observed X-ray scattering. The deviation factor R = 0.182 for all data with 10-2.4A resolution.