壳聚糖的配位控制氧化降解及量子化学研究

Metal-coordination controued oxidative degradation of chitosan and computional chemistry

提出一种新的壳聚糖降解法———金属配位控制氧化降解法 ,首先对壳聚糖实行人为特异性结构改造 ,将壳聚糖转化为壳聚糖金属配合物 ,再以H2 O2 对配合物进行氧化降解。对比金属配位控制氧化降解和直接氧化降解的反应结果 ,表明在相同降解条件下 ,前一种方法的降解速度明显高于后一种方法 ,且降解产物分子量分布较后者窄。半经验量子化学hyperchem6 .0 1ZIND0 /1模拟计算结果显示 ,壳聚糖金属配合物高分子链上配位糖元对应的糖苷键比其他糖苷键更容易发生断裂 ,壳聚糖链断裂优先发生在该位置 ,降解反应具有更好的选择性和可控性。

A method called metal-coordination controlled oxidative degradation was supplied for chitosan degradation.Chitosan was converted to chitosan-metal complex,and then H_2O_2 was used to depolymerize the complexes.Contrasting the results of metal-coordination controlled oxidative degradation with that of directly oxidative degradation,the degradation velocity of the former was exactly faster than that of the latter,and the molecular weight distribution of degraded chitosan by metal-coordination controlled oxitdative degradation was much more narrow than that of directly degraded chitosan at the same conditions.Semi-classical quantum chemistry method ZINDO/1 was used to calculate the structure of chitosan and chitosan-metal complexes.According to the bond length of C_1-O_1-C_4′,polymer chain of chitosan-metal complexes should be more easy to be broken than that of chitosan,and the broken site on complexes should be more selective and easier to be controlled.