Construction of five non-covalent-fabricated Zn2+/Cd2+ supramolecules from 3,5-dimethylpyrazole: Their synthesis and features

Abstract

The present report pertains to the synthesis and characterization of 5 novel complexes of Zn2(Hdmpz)4(L1)2(1) (L1 = itaconate), Cd(Hdmpz)2(L2) (2) (L2 = isophthalate), Cd(Hdmpz)2(L3) (3) (L3 = 5-amino-isophthalate), Zn(Hdmpz)2(L4)2(4) (L4 = 3-(4‑bromo-phenylcarbamoyl)-acrylate) and [Cd(Hdmpz)2(L4)2]2 • 2H2O (5). These complexes were elaborated from EA, IR and SCXRD analysis and the TGA of all the complexes was also identified.The X-ray studies told that these complexes display mononuclear to dinuclear structures with tetrahedral/octahedral arrangement around each Zn2+/Cd2+. The Hdmpzs in 1–5 are ligated only in monodentate fashion via its neutral N. The CO2− at 1 and 4 exhibits only unidentate coordination fashion, the CO2− in 2 and 3 show the chelating bidentate coordination mode. Compound 5 bear both unidentate bridging and bidentate chelating CO2−.The uncoordinated O of the CO2− in 1 makes the intramolecular NH•••O H-bond with NH of the Hdmpz. Compounds 2 and 3 bear the interchain NH•••O H-bonds from the Hdmpz and the coordinated O. The NH of one pyrazole at 4 made a bifurcated NH•••O H-bond with both O at the CONH and the uncoordinated O of the CO2−, the NH of the other pyrazole gave a single NH•••O H-bond to the CONH. At 5 the NH•••O H-bonds from the NH of the Hdmpz, the O at the CONH and the coordinated O of the CO2− were found. In the anions of 5 there also created the intramolecular NH•••O H-bond between the coordinated O and the CONH, building a S11(7) ring. The intricate intra- and intermolecular classical H-bonds, Br•••O, CHCH, CH3Cπ, CH-Br, CH•••O/CH2•••O/CH3•••O, CH•••π/CH2-π and CH3-π associations are elucidated by the X-ray crystallographic studies, which adhere the discrete units into high-dimensional ordered supramolecular structures.