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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。
Synthesis of Hexagonal Ligand N, N, N ’, N’-Tetrakis (2-Benzimidazolylmethylene) -1,2-Ethylenediamine (EDTB) and Mononuclear Manganese (Ⅱ) Complex [Mn )] (NO3) 2.DMF, and the crystal structure and polyphenol oxidase (PPO) mimic activity were studied. The complex is an orthorhombic, P212121 space group with a = 1.172 52 (6) nm, b = 1.320 83 (6) nm, c = 2.461 91 = 1.451 g.cm-3, Z = 4, F (000) = 1 732. R (all data): R1 = 0.0652, wR2 = 0.1075, Flack index 0.02 (15). The final factor R (I> 2σ (I)) is: R1 = 0.052 2, wR2 = 0.102 2; Structural analysis shows that manganese (Ⅱ) complexes with four nitrogen atoms and two imide nitrogen atoms of the EDTB benzimidazole ring, forming a deformed octahedral structure. Spectrophotometry was used to study the activity of polyphenol oxidase. Using pyrogallol as substrate, it was found that in the range of 0.1 ~ 10μmol.L-1, with the increase of the concentration of the complex, the oxidation promotion rate From 51.5% to 82.2%. Under 30 ℃, pH = 7.8 ~ 8.2, the conversion of the complex increased from 22.93 h-1 to 51.01 h-1, indicating that the PPO activity of the complex increased with the increase of pH value.