Chitin derivatives are difficult to be melten because of their very strong inter-molecular and intra-molecular hydrogen bonds. In this paper, N,O-benzyl chitosan was synthesized by means of phase-transfer method. The ...Chitin derivatives are difficult to be melten because of their very strong inter-molecular and intra-molecular hydrogen bonds. In this paper, N,O-benzyl chitosan was synthesized by means of phase-transfer method. The total degree of substitution for this derivative was 0 8 as determined with 1H NMR and the degree of substitution on nitrogen was 0 3 as determined with elemental analysis. This is a thermoplastic chitin derivative. Its melting point was 470 K as measured with DSC. A viscous isotropic melt occurred at the temperatures between the melting point and the decomposition temperature(513 K) while N,O-benzyl chitosan was heated on a hot stage. DSC results agreed with the results of microscopy observation. The benzyl group can not form hydrogen bonds. It is also non-polar and has larger volume. These factors weaken the interactions between chitosan chains, and therefore decrease the melting point, which was lower than the decomposition temperature. As a result, N,O-benzyl chitosan was able to melt.展开更多
以三苯基亚磷酸酯为双环金属化配体,2,2'-联吡啶-4,4'-二甲酸乙酯为辅助配体,合成了一种中性铱配合物(1).通过核磁共振波谱(NMR)、高分辨质谱(HRMS)及X射线单晶衍射分析对配合物的结构进行了确认.对配合物的光物理性能进行了表...以三苯基亚磷酸酯为双环金属化配体,2,2'-联吡啶-4,4'-二甲酸乙酯为辅助配体,合成了一种中性铱配合物(1).通过核磁共振波谱(NMR)、高分辨质谱(HRMS)及X射线单晶衍射分析对配合物的结构进行了确认.对配合物的光物理性能进行了表征,结果表明,掺杂于聚甲基丙烯酸甲酯(PMMA)中的配合物表现出黄光发射,波长为581 nm,量子效率高达29.4%,是含联吡啶羧酸类配体的铱配合物中最高的,发光寿命为1.08μs.配合物最高已占轨道(HOMO)能级为-5.43 e V,最低未占轨道(LUMO)能级为-3.18 e V.配合物表现出明显的聚集诱导发光增强性质,在水/四氢呋喃混合溶剂中,聚集后发光增强了17倍.用该配合物制备的掺杂有机电致发光器件的外量子效率高达8.9%,最大电流效率和功率效率分别为9.7 cd/A和5.2 lm/W.研究结果表明,双环金属化的亚磷酸酯配体对提高联吡啶羧酸酯类铱配合物的发光效率和扩展应用范围具有重要作用.展开更多
文摘Chitin derivatives are difficult to be melten because of their very strong inter-molecular and intra-molecular hydrogen bonds. In this paper, N,O-benzyl chitosan was synthesized by means of phase-transfer method. The total degree of substitution for this derivative was 0 8 as determined with 1H NMR and the degree of substitution on nitrogen was 0 3 as determined with elemental analysis. This is a thermoplastic chitin derivative. Its melting point was 470 K as measured with DSC. A viscous isotropic melt occurred at the temperatures between the melting point and the decomposition temperature(513 K) while N,O-benzyl chitosan was heated on a hot stage. DSC results agreed with the results of microscopy observation. The benzyl group can not form hydrogen bonds. It is also non-polar and has larger volume. These factors weaken the interactions between chitosan chains, and therefore decrease the melting point, which was lower than the decomposition temperature. As a result, N,O-benzyl chitosan was able to melt.
文摘以三苯基亚磷酸酯为双环金属化配体,2,2'-联吡啶-4,4'-二甲酸乙酯为辅助配体,合成了一种中性铱配合物(1).通过核磁共振波谱(NMR)、高分辨质谱(HRMS)及X射线单晶衍射分析对配合物的结构进行了确认.对配合物的光物理性能进行了表征,结果表明,掺杂于聚甲基丙烯酸甲酯(PMMA)中的配合物表现出黄光发射,波长为581 nm,量子效率高达29.4%,是含联吡啶羧酸类配体的铱配合物中最高的,发光寿命为1.08μs.配合物最高已占轨道(HOMO)能级为-5.43 e V,最低未占轨道(LUMO)能级为-3.18 e V.配合物表现出明显的聚集诱导发光增强性质,在水/四氢呋喃混合溶剂中,聚集后发光增强了17倍.用该配合物制备的掺杂有机电致发光器件的外量子效率高达8.9%,最大电流效率和功率效率分别为9.7 cd/A和5.2 lm/W.研究结果表明,双环金属化的亚磷酸酯配体对提高联吡啶羧酸酯类铱配合物的发光效率和扩展应用范围具有重要作用.
