摘要
The coordination structure of cupric tartrate(Cu−TA)complex was investigated by ultraviolet−visible(UV-Vis)and liquid chromatography/mass spectrometer(LC-MS)firstly;furthermore,effective coordination configurations and electronic properties of Cu−TA in aqueous solution were systematically revealed by density functional theory(DFT)calculations.Consistently,Job plots show the possible existence of[Cu(TA)]and[Cu(TA)_(2)]^(2-)at 230 and 255 nm based on UV-Vis results.LC-MS results confirm the existence of the single and high coordination complexes[Cu_(2)(TA)_(2)]^(+),[Cu(TA)_(2)]^(+)and[Cu_(2)(TA)_(3)(H_(2)O)_(2)(OH)_(2)]^(2+).DFT calculation results show that carboxylic oxygen and hydroxyl oxygen of tartaric acid(TA)are preferred sites for Cu(Ⅱ)coordination.[Cu(TA)](1H,3H sites O of TA coordinated with Cu(Ⅱ)),[Cu(TA)_(2)]^(2-)(two 1^(C),2^(H) sites O of TA coordinated with Cu(Ⅱ)),and[Cu(TA)_(3)]^(4-)(three 2H,3H sites O of TA coordinated with Cu(Ⅱ))should be dominant coordination configurations of Cu−TA.The corresponding Gibbs reaction energies are-170.1,-136.2,and-90.2 kJ/mol,respectively.
采用紫外可见光谱(UV-Vis)和液相色谱/质谱(LC-MS)分析酒石酸铜(Cu−TA)配合物的配位结构,并通过密度泛函理论(DFT)计算系统地揭示酒石酸铜在水溶液中的有效配位构型和电子特性。UV−Vis在230和255 nm处的Job图一致显示可能存在[Cu(TA)]和[Cu(TA)_(2)]^(2-)。LC−MS结果证实单配位和高配位配合物[Cu_(2)(TA)_(2)]^(+)、[Cu(TA)_(2)]^(+)和[Cu_(2)(TA)_(3)(H_(2)O)_(2)(OH)_(2)]^(2+)的存在。DFT计算结果表明,酒石酸(TA)的羧基氧和羟基氧是Cu(Ⅱ)的优选配位位点。[Cu(TA)](酒石酸分子1号碳的羟基氧和3号碳的羟基氧与Cu(II)配位)、[Cu(TA)_(2)]^(2-)(2个酒石酸分子1号碳的羧基氧和2号碳的羟基氧与Cu(Ⅱ)配位)以及[Cu(TA)_(3)]^(4-)(3个酒石酸分子2号碳的羟基氧和3号碳的羟基氧与Cu(Ⅱ)配位)是酒石酸铜的主要配位构型。三者的吉布斯自由能分别为-170.1、-136.2和-90.2 kJ/mol。
基金
the National Key Research and Development Program of China(No.2019YFC0408303)
the Natural Science Foundation of Hunan Province,China(No.2021JJ20069)
the Changsha Science and Technology Project,China(Nos.kq2106016,kq2009005)
Higher Education Discipline Innovation Project(111 Project),China(No.B14034)
the Fundamental Research Funds for the Central Universities of Central South University,China(No.2021zzts0887).
