Some five-coordinated cobalt(III) complexes were synthesized and characterized using elemental analysis, 1H NMR and IR spectra. The formation constants and the thermodynamic parameters were measured spectrophotometrically for the 1:1 adduct formation of [Co(Chel)(PBu3)]ClO4.H2O where Chel = cd3OMesalen, cd4OMesalen, cd5OMesalen: methyl-2-[1-methyl-2-(2-hydroxy-3-, 4-, 5-methoxyphenyl)methylidynen-itrilo]ethyl}amino-1-cyclopentene-dithiocarboxylate, as acceptors, with some linear and cyclic amines as donors, in different solvents at constant ionic strength (I = 0.1 M NaClO4), and at various temperatures (T = 283-313 K). The results revealed that the formation constants of the Co(III) Schiff base complexes toward a given amines donor are as follow: [Co(cd4OMesalMeen)(PBu3)]+ > [Co(cd3OMesalMeen)(PBu3)]+ > [Co(cd5OMesalMeen)(PBu3)]+. The trend of the formation constants of the donors (amines) toward a given cobalt(III) complex is as follow: Im > 4-MeIm > BzIm and n-butylamine > sec-butylamine > tert-butylamine. Also the effect of the solvents on the formation constants of a given cobalt(III) Schiff base complex toward a given donor are as follow: CH3CN > DMF > EtOH. The ligands and their cobalt complexes have been screened for their antibacterial activities. All the free Schiff base ligands exhibit higher antibacterial activity than the cobalt(III) complexes.
利用元素分析、1H NMR 和 IR 光谱合成并表征了一些五配位
钴(III)配合物。通过分光光度法测量了 [Co(Chel)(PBu3)]ClO4 的 1:1 加合物形成的形成常数和热力学参数。
H2O 其中,Chel = cd3OMesalen、cd4OMesalen、cd5OMesalen:甲基-2-[1-甲基-2-(2-羟基-3-、4-、5-
甲氧基苯基)甲基亚硝基氮]乙基}
氨基-1-
环戊烯-二
硫代
羧酸酯作为受体,一些线性胺和环状胺作为供体,在不同溶剂中,在恒定离子强度(I = 0.1 M NaClO4)和不同温度(T = 283-313 K)下在不同溶剂中进行。结果表明,Co(III) 希夫碱配合物对特定胺供体的形成常数如下:[Co(cd4OMesalMeen)(PBu3)]+>[Co(cd3OMesalMeen)(PBu3)]+>[Co(cd5OMesalMeen)(PBu3)]+。给体(胺)对特定
钴(III)络合物的形成常数趋势如下:Im>4-MeIm>BzIm,
正丁胺>
仲丁胺>
叔丁胺。此外,溶剂对特定
钴(III)希夫碱络合物与特定供体的形成常数的影响如下:CH3CN >
DMF > EtOH。对
配体及其
钴配合物进行了抗菌活性筛选。所有游离希夫碱
配体的抗菌活性都高于
钴(III)配合物。