Supramolecular Architectures And Photoluminescent Properties Of Triethanolammonium 4-Nitrobenzoate Salt And Its Ni(Ii) Complexes

Single crystals of new organic salt (HTEA)(4NB) (1) and its different types of Ni(II) complexes obtained from the same system NiCl2-compound 1 under various experimental conditions: [Ni(4NB)(TEA)(H2O)] (4NB) (2), [Ni(4NB)(TEA)(H2O)](4NB)center dot H2O (3), [Ni(TEA)(2)](4NB)(2) (4) and Ni(BIC)(2) (5), where TEA = triethanolammine, 4NB = 4-nitrobenzoate and BIC = N,N-bis(2-hydroxyethyl) glycinate, were successfully synthesized and structural characterized by FTIR spectroscopy and single crystal X-ray analysis. All new compounds represent supramolecular systems assembled by combining two or three organizing forces: metal-coordination (2-5), hydrogen bonds (1-5) and pi-pi stacking interactions (1-4). In compounds 2 and 3 the Ni(II) atom has an identical NO5 environment, while in complex 4 and 5 the metal centres have a N2O4 coordination core. The ionic coordination complexes 2-4 are arranged into 2D hydrogen-bonding layers and further assembled via pi-pi stacking interactions in supramolecular 3D network structures, while complex molecules of 5 are organized into a hydrogen-bonded network. This study emphasizes the first structurally characterized binary glycinate Ni(II) complex obtained from NiCl2 center dot 6H(2)O-(HTEA)(4NB) system. Comparative solid-state photoluminescent study of four Ni(II) coordination compounds and initial organic salt reveals a correlation between crystal structure/packing and luminescent properties. (C) 2020 Elsevier Ltd. All rights reserved.