Heterobimetallic M/Zn (M = Cu, Ni) complexes with open-chain N- and N,O-ligands: Template synthesis from metal powders and supramolecular crystal structures

Abstract

A series of new heterometallic Cu IIZn II and Ni IIZn II complexes with N- and N,O open-chain multidentate ligands (L 1 = 4,6,6-trimethyl-1,9-diamino-3,7-diazanon-3-ene; L 2 = 3,7-bis(2-aminoethyl)-1,3,5,7-tetraazabicyclo[3.3.1]nonane; L 3 = 1,15-dihydroxy-7,9,9-trimethyl-3,6,10,13-tetraazapentadec-6-ene and L 4 = 1-hydroxy-9-oxy-4,6,6-trimethyl-3,7-diazanon-3-ene) have been prepared through the “direct template synthesis” approach, which is a combination of classical template reactions of amines with acetone/formaldehyde and the “direct synthesis” method based on using elemental metals as starting materials. There is a significant decrease in the reaction time when the “direct synthesis” method is used compared to the conventional template condensation methods. X-ray crystallographic analyses of the complexes with the general formula M(L)ZnX 4 and [CuL 4ZnCl 3] 2 (M = Cu 2+, Ni 2+; L = L 1-L 3; X = Cl −, NCS −) reveal the presence of long intermolecular distance interactions, such as semi-coordination, S⋯S and H-bonding, in their crystal organization.