Structurally well-characterized new multinuclear Cu( ii ) and Zn( ii ) clusters: X-ray crystallography, theoretical studies, and applications in catalysis

Two new trinuclear Cu( ii ) and dinuclear Zn( ii ) clusters are crystallized out by reacting the metal salts with the triethanolamine (H 3 tea) ligand in the presence of benzoic acid (Hba). The complexes are characterized by elemental, thermal, magnetic, spectral (FTIR, UV-Visible, EPR, and photoluminescence) and single crystal X-ray studies. Single crystal X-ray crystallography reveals the composition of the complexes to be [Cu 3 (H 2 tea) 2 (ba) 2 (NO 3 ) 2 ] ( 1 ) and [Zn 2 (H 2 tea)(ba) 3 ]H 2 O ( 2 ). FTIR ascertains the binding modes of H 2 tea − , ba − and NO 3 − . Triethanolamine binds in both the complexes in the monoanionic (H 2 tea − ) mode. ba − is present as an anchoring auxiliary to generate di- and trinuclear clusters. The Cu( ii ) ion is present as a distorted octahedral center in the Cu 3 cluster ( 1 ), while the two Zn( ii ) ions in 2 have been reported for the first time to possess distorted octahedral as well as tetrahedral geometry in the same molecule. The intriguing features of the non-covalent supramolecular interactions have been investigated and supported theoretically by using Hirshfeld surface analysis and ab initio methods. The solid state photoluminescence (PL) spectra of 1 and 2 disclose the luminescence property of the complexes. Due to the closed or nearly closed shell configuration (d 9 or d 10 ), the present complexes are screened for catalytic properties in the hydrocarboxylation of alkanes and cycloalkanes. The catalytic activity data are indicative of the potential catalytic properties of 1 and 2 .