Supramolecular self-assembly of M-IDA complexes involving lone pair center dot center dot center dot pi interactions: crystal structures, Hirshfield surface analysis, and DFT calculations [H(2)IDA =iminodiacetic acid, M = Cu(II), Ni(II)]

Abstract

[eng] Mononuclear copper(II) and nickel(II) complexes, [(C5H6N2)Cu(IDA)(H2O)] (1) and (C5H7N2)2[Ni(IDA)2(H2O)] (2) [H2 IDA = iminodiacetic acid; C5H6N2 = 4-aminopyridine; C5H7N2 = protonated 2-aminopyridine], have been synthesized, and their crystal structures were solved using single crystal X-ray diffraction data. A detailed analysis of Hirshfeld surfaces and fingerprint plots facilitates a comparison of intermolecular interactions, which are crucial in building different supramolecular architectures. Molecules are linked by a combination of N H3 3 3 O, O H3 3 3O and C H3 3 3O hydrogen bonds into two-dimensional framework, whose formation is readily analyzed in terms of substructures of lower dimensionality with zero finite zero-dimensional dimeric units as the building blocks within the structures. Moreover, the aromatic molecules that are engaged in lone pair 3 3 3 π interactions with the noncoordinated carbonyl moieties play a crucial role in stabilizing the self-assembly process observed for both complexes. Intricate combinations of hydrogen bonding, lone pair 3 3 3 π and π π interactions are fully described along with the computational studies.