基于5-甲基-3-吡唑甲酸为配体的钴(Ⅱ)、镍(Ⅱ)配合物的合成、晶体结构和电化学性质

利用5-甲基-3-吡唑甲酸、咪唑和相应醋酸盐在乙醇和水混合溶剂中反应,得到了配合物M(MPA)2(Im)2].2H2O(1:M=Co;2:M=Ni)(HMPA=5-甲基-3-吡唑甲酸,Im=咪唑)。用元素分析、红外光谱、X-单晶衍射结构分析、热重分析、循环伏安等对其进行了表征。配合物1和2的晶体结构参数如下:配合物1和2的晶体都属于单斜晶系,空间群为P21/n。配合物1的晶胞参数为a=0.847 02(16)nm,b=1.461 5(3)nm,c=0.899 67(17)nm,β=101.759(6)°,V=1.090 3(4)nm3,Z=2;配合物2的晶胞参数为a=0.853 59(6)nm,b=1.451 77(9)nm,c=0.889 83(6)nm,β=102.382 0(10)°,V=1.077 04(12)nm3,Z=2。金属离子与来自2个5-甲基-3-吡唑甲酸配体中的2个氮原子及2个氧原子,2个咪唑分子中的2个氮原子配位,形成八面体配位构型。配合物中的独立结构单元M(MPA)2(Im)2].2H2O通过2种分子间氢键(N-H…O和C-H…O)形成三维超分子。循环伏安性质测试表明配合物1和2的电解过程均为准可逆过程。

Syntheses, Crystal Structures and Electrochemical Properties of Cobalt and Nickel Complexes Based on 5-Methyl-1H-pyrazole-3-carboxylic Acid Ligand

The new monomeric complexes of M(MPA)2(Im)2].2H2O(1:M=Co;2:M=Ni)(HMPA=5-methyl-1H-pyrazole-3-carboxylic acid,Im=imidazole) were synthesized by the reaction of HMPA and Im with M(OAc)2.4H2O(M=Co,Ni),respectively.The compounds were characterized by elemental analysis,IR spectra,single crystal X-ray diffraction,thermogravimetric analysis and cyclic voltammetry.The structural parameters of 1 and 2 were analyzed as follows:1,monoclinic,P21/n,a=0.847 02(16) nm,b=1.461 5(3) nm,c=0.899 67(17) nm,β=101.759(6)°,V=1.090 3(4) nm3,Z=2;2,monoclinic,P21/n,a=0.853 59(6) nm,b=1.451 77(9) nm,c=0.889 83(6) nm,β= 102.382 0(10)°,V=1.077 04(12) nm3,Z=2.Metal ions have all octahedral geometry coordinated by two nitrogen atoms from two Im molecules,two nitrogen atoms and two oxygen atoms from two MPA-ligands.In both complexes,the independent components M(MPA)2(Im)2].2H2O are connected by two kinds of intermolecular hydrogen bonds(N-H…O and C-H…O) to form a three-dimensional supramolecular architecture.Electrochemical property of the complex shows that electron transfer of M(Ⅱ) between M(Ⅲ)(M=Co,Ni) in electrolysis is quasi-reversible process.