Constructions of seven noncovalent-bonded supramolecules from reactions of Cu(II)/Cd(II)/Zn(II) with isonicotinamide and carboxylates

Abstract

Transition metal carboxylates with O- and N-donor ligands are interesting for their structural features. Seven novel isonicotinamide(inic)-based metal complexes of [Cd(inic)2(L1)2(H2O)2] · 2H2O (1) (L1 = 2-chloronicotinate), [Cd(inic)2(L2)2(H2O)2] (2) (L2 = 2,4-dichlorobenzoate), [Cu(inic)2(L3)2] (3) (L3 = 4-chlorophenoxyacetate), [Cu3(inic)6(L4)2(HL4)2(H2O)2] · 2H2O (4) (L4 = azelate), [Zn(inic)2(L1)2(H2O)2] · (inic) · H2O (5), [Zn(inic)(L5)(H2O)4] (6) (L5 = 3-nitrophthalate) and [Zn2(inic)2(L6)2] · 5H2O (7) (L6 = 1,4-cyclohexanedicarboxylate) have been obtained by the introduction of the carboxylates by the common solution method and are structurally featured by different techniques of EA, IR spectra, TG and SCXRD analysis. The X-ray studies told that these complexes display mononuclear to trinuclear structures with octahedral/square-pyramidal geometry around the Zn2+, trigonal bipyramidal/octahedral at the Cu2+ and octahedral for the Cd2+. The inic in 1–7 are coordinated only in monodentate fashion with its ring N, while 5 has the lattice inic. The carboxylates coordinated to the metal in monodentate, chelating bidentate and bridging bidentate fashions. The pair of complementary N-H···O H-bonds from the CONH2 of the inic were found in all compounds except 7. Except 1 and 2, all other compounds bear the CH-O contacts from the pyridine CH of the inic. The intricate intra- and intermolecular classical H-bonds, CH-N, CH-O, CH-Cl, CH2-O, O-N, O-O, Cl-O, Cl-Cl, CH-π, CH2-π, C-π, N-π, Cl-π and π-π associations are elucidated by the X-ray crystallographic studies, which push the discrete complexes into high-dimensional ordered supramolecular structures.