Copper(II) complexes of 6-hydroxymethyl-substituted tris(2-pyridylmethyl)amine ligands †

Three potentially tripodal, tris(2-pyridylmethyl)amine (tpa) ligands with hydroxymethyl substituents, [6-(hydroxymethyl)-2-pyridylmethyl]bis(2-pyridylmethyl)amine (HL1), bis[6-(hydroxymethyl)-2-pyridylmethyl]2-(pyridylmethyl)amine (H2L2), tris[6-(hydroxymethyl)-2-pyridylmethyl]amine (H3L3), have been prepared in good yields. From these ligands, the copper(II) co-ordination complexes [Cu(HL1)Cl]Cl 1, [Cu(H2L2)Cl]X (X = Cl 2 or p-toluenesulfonate 3), [Cu(L2BF2)][BF4] 4 a complex of a novel macrocyclic anion with a tpa core, [Cu(H3L3)Br0.43Cl0.57]2[Cu(Br0.43Cl0.57)2(Br0.97Cl0.03)2] 5 with compositionally disordered bromo and chloro co-ligands, [Cu(H3L3)Br]Br 6 and the unusual trimer [Cu3{H3(L3)2}Br][BF4]27 have been synthesized and their spectroscopic and redox properties and crystal structures obtained.