应用有机结构数据库系统研究钼簇合物的键价规律

SYSTEMATICAL RESEARCH ON THE BOND VALENCES OF MOLYBDENUM CLUSTER COMPOUNDS WITH CAMBRIDGE STRUCTURAL DATABASE

本文基于有机结构数据库CSD中簇合物的大量信息,依靠计算机检索、图形显示和运算功能,系统分析了449个钼簇合物的价电子总数和Mo-Mo键的键价,键长,提出钼簇合物的价电子Counting规则和Mo-Mo键的总键价计算修正公式,总结出Mo-Mo键的键价、健长等。

Based on the structural information on 449 molybdenum cluster compounds inCSD (Cambridge Stuctural Database), the sum of valence electrons of molybdenumclusers, the average bond valences of Mo-Mo and the average bond lengths of Mo-Mo have been calculated. The current method uses the functions of retrieval, molecularplots and statistics in CSD. It is suggested that the valence electron counting rule ofmolybdenum cluster compouds is:The sum of valence electrons of molybdenum cluster(k)+the sum of bondvalences for Mo-Mo×2=18×n-2×∑Δ_iand the sum of bond valence for Mo-Mo can be counted by using the formula: v=(18×n-k)/2-∑Δ_ithe geometry configurations of molybdenum clusters, the distribution of the bondvalences, bond lengths of Mo-Mo, the electronegativity of ligands, and their rela-tions have been systematically analysed. the results proved that the bond lengthes ofMo-Mo with equal bond valence are mainly influenced by the electronegativity ofligands. The larger the electronegativity of ligands, the shorter the bond lengths ofMo-Mo with equal bond valence.