配合物[Mn(EDTB)](NO_3)·_2DMF的合成、晶体结构及多酚氧化酶(PPO)活性的研究

Synthesis and Crystal Structure of Complex [Mn(EDTB)](NO_3)_2·DMF and Its Polyphenol Oxidase Activity

合成六齿配体N,N,N′,N′-四(2-苯并咪唑亚甲基)-1,2-乙二胺(EDTB)及单核锰(Ⅱ)配合物[Mn(EDTB)](NO3)2.DMF,并进行了晶体结构和多酚氧化酶(PPO)模拟活性研究。该配合物为正交晶系,P212121空间群,a=1.172 52(6)nm,b=1.320 83(6)nm,c=2.461 91(12)nm,V=3.812 8(3)nm3,Dc=1.451 g.cm-3,Z=4,F(000)=1 732。最终因子R(I>2σ(I)):R1=0.052 2,wR2=0.102 2;R(全部数据):R1=0.0652,wR2=0.1075,Flack指数为0.02(15)。结构分析表明,锰(Ⅱ)分别与配体EDTB苯并咪唑环的4个氮原子、两个亚胺基氮原子发生配位,形成1个变形八面体结构。采用分光光度法研究配合物的多酚氧化酶活性,以邻苯三酚为底物,表明在0.1～10μmol.L-1范围内,随着配合物浓度逐渐增大,配合物的氧化促进率从51.5%增至82.2%。在30℃,pH=7.8～8.2条件下,配合物的转化数由22.93 h-1增加到51.01 h-1,说明配合物的PPO活性随着pH值的升高而明显增强。

The title complex [Mn（EDTB）]（NO3）2·DMF [EDTB=N,N,N′,N′-tetrakis-[（2-benzimidazolyl） methyl]-1,2-ethanediamine] has been synthesized and characterized by elemental analysis and single crystal X-ray diffraction method.The crystal of mononuclear Mn（Ⅱ） complex belongs to orthorhombic crystal system with space group,P212121,a=1.172 52（6） nm,b=1.320 83（6） nm,c=2.461 91（12） nm,V=3.812 8（3） nm3,Dc=1.451 Mg·m-3,Z=4,F（000）=1 732.The final R（I2σ（I））：R1=0.052 2,wR2=0.102 2 and R（all data）：R1=0.065 2,wR2=0.107 5,Flack parameter：0.02（15）.The manganese（Ⅱ） atom of the cation has distorted octahedral coordination geometry and is six-coordinated by four nitrogen atoms of the benzimidazole groups and two tertiary amine nitrogen atoms from the ligand.Polyphenol oxidase activity toward pyrogallol has been studied spectroscop ically.In the 0.1～10 μmol·L-1 rang,promotion rates of the complex increase from 51.5% to 82.2%.The turnover numbers of the complex toward pyrogallol increase from 22.93 h-1 to 51.01 h-1 at 30 ℃,showing polyphenol oxidase activity of the complex increasing with pH.CCDC：771022.