Synthesis and properties of a tetraaza macrocyclic ligand containing 2-pyridylmethyl pendant arms and its copper(II) and nickel(II) complexes: crystal structure of the copper(II) complex

摘要

A new functionalized macrocyclic ligand 2,13-bis(2'-pyridylmethyl)-5, 16-dimethyl-2,6, 13,17-tetraazatricyclo[16.4.0.O-1.18(7.12)]docosane (L-2) containing two 2-pyridylmethyl pendant arms has been prepared by the one-step reaction of 3,4-dimethyl-2,6, 13,17-tetraazatricyclo[ 16.4.0.O-1.18(7.12)]docosane (L-1) with 2-(chloromethyl) pyridine. The octahedral complexes [NiL2](ClO4)(2) and [CuL2](ClO4)(2), in which two pyridyl groups are coordinated to the metal ion, have been prepared and characterized. The crystal structure of [CuL2](ClO4)(2) shows that the complex is centrosymmetric and the metal center has a tetragonally distorted octahedral geometry. In concentrated HClO4 solutions, the coordinated pyridyl groups of [CuL2](2+) are protonated and are removed from the coordination sphere. However, those of [NiL2](2+) are not protonated but are coordinated to the metal ion even in 3.0M HClO4. The macrocycle L-2 reacts more slowly with copper(II) ion than does L-1. (C) 1998 Elsevier Science Ltd. All rights reserved. [References: 40]