Liu C W, Lobana Tarlok S, Santra Bidyut K, Hung Chiu-Mine, Liu Hong-Yuan, Liaw Ben-Jie, Wang Ju-Chun
Department of Chemistry, National Dong Hwa University, Hualien, 974, Taiwan.
Dalton Trans. 2006 Jan 28(4):560-70. doi: 10.1039/b510728h. Epub 2005 Oct 25.
The reactions of diselenophosphates, [dsep, (RO)2PSe2-; R = Et, (n)Pr and (i)Pr] with cadmium(II) and mercury(II) perchlorates in a 2 : 1 molar ratio formed compounds of stoichiometry M[Se2P(OR)2]2{M = Cd, R = Et (1), (n)Pr (2), (i)Pr (3); Hg, Et(4), (n)Pr (5), (i)Pr (6)}, and with zinc(II) perchlorates, chalcogen centered tetranuclear clusters, [Zn4(micro4-E){Se2P(OR)2}6]{E = Se, R = Et (7), (n)Pr (8), (i)Pr (9); E = O, R = Et (10), (n)Pr (11), (i)Pr (12)} were formed. All these complexes have been characterized with the help of analytical data, X-ray crystallography (1, 3, 6, 10, 11 and 12), and FAB-mass spectrometry (7-12). Compound 1 is a linear double-chain polymer, in which each pair of Cd atoms is bridged by two dsep ligands; the mercury 6 polymer has a helical chain structure, in which two Hg atoms are bridged by one dsep ligand, and the other ligand chelates the Hg atom. The chelating dsep ligands lie on either side of the helical chain. Compound 3 exists as a dimer in which two cadmium atoms are connected by two bridging dsep ligands, and each cadmium atom is further chelated by a dsep ligand. The metal atoms in 1, 3 and 6 are each coordinated by four selenium atoms in a distorted tetrahedral geometry. Clusters 10-12 have tetrahedral array of zinc atoms with an oxygen atom in the center with edge-bridging dsep ligands. Positive FAB-mass spectra support the formation of selenium-centered clusters,7-9, of which the cluster 8 was structurally confirmed earlier. The solution state behavior of compounds 1-12 has been studied by using multinuclear NMR spectroscopy. Dimer 3 in CD2Cl2 showed monomer-dimer exchange equilibrium in the temperature range 20 to -90 degrees C and the free energy of activation is calculated from the coalescence temperature as DeltaG++(223 K)= 38.5 kJ mol(-1). Polymer undergoes depolymerization in CDCl3 and exhibits monomer-dimer exchange equilibrium in the temperature range 20 to -60 degrees C.
二硒代磷酸酯（[dsep，(RO)2PSe2-；R = 乙基、正丙基和异丙基]）与高氯酸镉（II）和高氯酸汞（II）按2:1的摩尔比反应，形成化学计量比为M[Se2P(OR)2]2的化合物{M = 镉，R = 乙基（1）、正丙基（2）、异丙基（3）；汞，乙基（4）、正丙基（5）、异丙基（6）}，与高氯酸锌（II）反应，则形成以硫族元素为中心的四核簇合物，[Zn4(μ4-E){Se2P(OR)2}6]{E = 硒，R = 乙基（7）、正丙基（8）、异丙基（9）；E = 氧，R = 乙基（10）、正丙基（11）、异丙基（12）}。所有这些配合物均借助分析数据、X射线晶体学（1、3、6、10、11和12）以及快原子轰击质谱（7 - 12）进行了表征。化合物1是一种线性双链聚合物，其中每对镉原子由两个dsep配体桥联；汞的聚合物6具有螺旋链结构，其中两个汞原子由一个dsep配体桥联，另一个配体螯合汞原子。螯合的dsep配体位于螺旋链的两侧。化合物3以二聚体形式存在，其中两个镉原子由两个桥联的dsep配体连接，且每个镉原子进一步被一个dsep配体螯合。1、3和6中的金属原子各自以扭曲的四面体几何构型与四个硒原子配位。簇合物10 - 12具有锌原子的四面体排列，中心有一个氧原子，dsep配体在边缘桥联。正的快原子轰击质谱支持以硒为中心的簇合物7 - 9的形成，其中簇合物8的结构先前已得到证实。通过多核NMR光谱研究了化合物1 - 12的溶液状态行为。二聚体3在CD2Cl2中在20至 - 90℃的温度范围内显示出单体 - 二聚体交换平衡，并且根据聚结温度计算出活化自由能为ΔG++(223 K)= 38.5 kJ mol(-1)。聚合物在CDCl3中发生解聚，并在20至 - 60℃的温度范围内表现出单体 - 二聚体交换平衡。
