Department of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India.
Carbohydr Res. 2011 Oct 18;346(14):2075-83. doi: 10.1016/j.carres.2011.06.030. Epub 2011 Jun 28.
We have studied the binding interactions of biologically important carbohydrates (D-glucose, D-xylose and D-mannose) with the newly synthesized five-coordinate dinuclear copper(II) complex, [Cu(2)(hpnbpda)(μ-OAc)] (1) and zinc(II) complex, [Zn(2)(hpnbpda)(μ-OAc)] (2) [H(3)hpnbpda=N,N'-bis(2-pyridylmethyl)-2-hydroxy-1,3-propanediamine-N,N'-diacetic acid] in aqueous alkaline solution. The complexes 1 and 2 are fully characterized both in solid and solution using different analytical techniques. A geometrical optimization was made of the ligand H(3)hpnbpda and the complexes 1 and 2 by molecular mechanics (MM+) method in order to establish the stable conformations. All carbohydrates bind to the metal complexes in a 1:1 molar ratio. The binding events have been investigated by a combined approach of FTIR, UV-vis and (13)C NMR spectroscopic techniques. UV-vis spectra indicate a significant blue shift of the absorption maximum of complex 1 during carbohydrate coordination highlighting the sugar binding ability of complex 1. The apparent binding constants of the substrate-bound copper(II) complexes have been determined from the UV-vis titration experiments. The binding ability and mode of binding of these sugar substrates with complex 2 are indicated by their characteristic coordination induced shift (CIS) values in (13)C NMR spectra for carbon atoms C1, C2, and C3 of sugar substrates.
我们研究了具有重要生物学意义的碳水化合物（D-葡萄糖、D-木糖和 D-甘露糖）与新合成的五配位双核铜（II）配合物[Cu2（hpnbpda）（μ-OAc）]（1）和锌（II）配合物[Zn2（hpnbpda）（μ-OAc）]（2）[H3hpnbpda=N，N'-双（2-吡啶甲基）-2-羟基-1,3-丙二胺-N，N'-二乙酸]在水堿性溶液中的结合相互作用。配合物 1 和 2 在固相中以及在溶液中均通过不同的分析技术进行了充分的表征。通过分子力学（MM+）方法对配体 H3hpnbpda 和配合物 1 和 2 进行了几何优化，以确定稳定的构象。所有碳水化合物都以 1:1 的摩尔比与金属配合物结合。结合事件通过傅里叶变换红外光谱（FTIR）、紫外-可见光谱和（13）C NMR 光谱技术的综合方法进行了研究。紫外-可见光谱表明，在碳水化合物配位过程中，配合物 1 的吸收最大值发生了显著的蓝移，突出了配合物 1 的糖结合能力。通过紫外-可见滴定实验确定了底物结合的铜（II）配合物的表观结合常数。这些糖底物与配合物 2 的结合能力和结合模式通过它们在（13）C NMR 光谱中碳原子 C1、C2 和 C3 的特征配位诱导位移（CIS）值来指示。
