Synthesis, Characterization and Crystal Structures of Monomeric and Imidazolate-Bridged Polymeric Copper(II) Complexes of 5-Methyl-1,5,9-triazanonane

Abstract

Two complexes [Cu(mtan)(H₂O)(ClO₄)](ClO₄) (Im = imidazolate) (1) and [Cu(mtan)(Im)]_n (ClO₄)_2n (mtan = 5-methyl-1,5,9-triazanonane) (2) have been prepared and characterized. Single-crystal X-ray analysis reveals that (1) crystallizes in the orthorhombic space group Pbcm, with a 8.906(5), b 12.255(6), c 14.821(4) Å and V 1618(1) ų, and complex (2) crystallizes in the orthorhombic space group Pca2₁, with a 11.125(7), b 9.149(6), c 15.180(7) Å and 1545(1) ų. The copper(II) atom in complex (1) is in a distorted square-pyramidal geometry, being coordinated by three nitrogen atoms from an mtan ligand and one oxygen atom from an aqua ligand at the basal plane and one perchlorate oxygen atom at the apical position. The structure of complex (2) features polymeric cationic chains composed of [Cu(mtan)(Im)]⁺ repeating units and discrete perchlorate anions. The Cu(1) atom in each unit has a severely distorted trigonal-bipyramidal geometry, being coordinated by three nitrogen atoms from one mtan ligand and two nitrogen atoms from two Im groups. The structural units are linked by -Im groups to give one-dimensional chains. The variable-temperature magnetic measurement on the powder sample of (2) reveals intrachain, medium antiferromagnetic interaction with g = 2.240 and J = –36.45 cm^–1 through the -Im bridges.