Inter-ligand interactions and the selective formation of the unusual metal–N3(adenine) bond in ternary copper(II) complexes with N-benzyliminodiacetato(2−) ligands

A novel mixed-ligand copper(II) complex with N-(p-methoxybenzyl)-iminodiacetato(2−) ligand (MOBIDA) and adenine (AdeH) of formula [Cu(MOBIDA)(AdeH)(H2O)]·H2O has been obtained. Its crystal structure reveals the selective formation of a rare Cu–N3(AdeH) bond, closely related to those reported by first time for compounds of general formula [Cu(B)(AdeH)(H2O)]·H2O, with B=N-benzyl- or N-(p-methylbenzyl)-iminodiacetato(2−) ligands. Appropriate structural comparison reveals that the copper(II) coordination by less basic N3 heterocyclic donor of the nucleobase is controlled by a molecular recognition process involving the formation of an intra-molecular inter-ligand N7(imidazole-like)–H⋯O(carboxyl) bond and the inter-molecular inter-ligand π,π-stacking interaction between six membered rings of benzyl (MOBIDA) and AdeH. This stack generates multi-stacked infinite chains along the b-axis of the crystal.