Acid–base equilibria of co-ordinated ligands. Part 1. The effect of basicity of co-ordinated nitrogen donors upon the acidity of chelating 8-aminoquinoline in some dicationic platinum(<scp>II</scp>) complexes
Cationic complexes of the type [Pt(8NH2-quin)L2][ClO4]2, and [Pt(8NH2-quin)(L–L)][ClO4]2(8NH2-quin = 8-aminoquinoline), where L and L–L are mono- and bi-dentate nitrogen donors respectively, have been prepared. In aqueous solution, they undergo reversible deprotonation of the amino group of the quinoline ligand. The corresponding ionization constants (Kac) have been determined by UV/VIS spectrophotometry
[Pt(8NH 2 -quin)L 2 ] [ClO 4 ] 2和[Pt(8NH 2 -quin)(L–L)] [ClO 4 ] 2(8NH 2 -quin = 8型)的阳离子络合物氨基喹啉),其中L和L–L分别是单齿和双齿氮供体。在水溶液中,它们经历喹啉配体的氨基的可逆去质子化。相应的电离常数(K a c)已通过25°C和I = 0.1 mol dm –3的UV / VIS分光光度法测定。线性自由能关系p K a c =α+βpķ一个大号被验证为对位取代的phyridines,P ķ一个大号参照L的水的碱度在25℃。