Dinuclear, star-shaped tetranuclear and trinuclear-based two-dimensional metal complexes derived from a less investigated Schiff base ligand: Syntheses, crystal structures and spectroscopic correlation

Bioactive Heterometallic CuII-ZnII Complexes with Potential Biomedical Applications

A series of multinuclear heterometallic Cu-Zn complexes of molecular formula [(CuL)₂Zn(dca)₂] (1), [(CuL)₂Zn(NO₃)₂] (2), [(CuL)₂Zn₂(Cl)₄] (3), and [(CuL)₂Zn₂(NO₂)₄] (4) have been synthesized by reacting [CuL] as a "metalloligand (ML)" (where HL = N,N'-bis(5-chloro-2-hydroxybenzylidene)-2,2-dimethylpropane-1,3-diamine) and by varying the anions or coligands using the same molar ratios of the reactants. All of the four products including the ML have been characterized by infrared and UV-vis spectroscopies and elemental and single-crystal X-ray diffraction analyses. By varying the anions, different structures and topologies are obtained which we have tried to rationalize by means of thorough density functional theory calculations. All of the complexes (1-4) have now been applied for several biological investigations to verify their therapeutic worth. First, their cytotoxicity properties were assessed against HeLa human cervical carcinoma along with the determination of IC₅₀ values. The study was extended with extensive DNA and protein binding experiments followed by detailed fluorescence quenching study with suitable reagents to comprehend the mechanistic pathway. From all of these biological studies, it has been found that all of these heterometallic complexes show more than a few fold improvement of their therapeutic values as compared to the similar homometallic ones probably because of the simultaneous synergic effect of copper and zinc. Among all of the four heterometallic complexes, complex 3 exhibits highest binding constants and IC₅₀ values suggest for their better interaction toward the biological targets and hence have better clinical importance.

Joining of trinuclear (CuL)2M (M = MnII and CdII) nodes by 1,3- and 1,4-benzenedicarboxylate linkers: positional isomeric effect on co-crystallization

Among the four one-dimensional coordination polymers obtained by joining (CuL)₂M (M = Mn^II and Cd^II) nodes with 1,3- and 1,4-benzenedicarboxylate linkers, the chains derived from 1,3-benzenedicarboxylate are co-crystallized with dimeric Cu^II units.

Syntheses, crystal structures, magnetic properties and ESI-MS studies of a series of trinuclear CuIIMIICuII compounds (M = Cu, Ni, Co, Fe, Mn, Zn)

Six homo/heterotrinuclear Cu^IIM^IICu^II (M = Mn–Zn) compounds derived from salicylaldehyde-trans-1,2-diaminocyclohexane, which is a rarely utilized ligand, are reported.

A nickel(ii)–manganese(ii)-azido layered coordination polymer showing a three-dimensional ferrimagnetic order at 35 K

The synthesis, crystal structure and magnetic properties of a two-dimensional nickel(ii)–manganese(ii)–azido system are described. It is an interesting molecular magnet because it exhibits long-range ferrimagnetic ordering at a T_c of 35 K and a hysteresis loop up to 20 K.

Syntheses, crystal structures, magnetochemistry and catechol oxidase activity of a tetracopper(ii) compound and a new type of dicopper(ii)-based 1D coordination polymer

One phenoxo–hydroxo bridged tetranuclear cluster and one phenoxo-µ_1,1-azido-µ_1,3-azido bridged one-dimensional coordination polymer of copper(ii) derived from a Schiff base ligand are described.

Synthesis, structural characterization and thermal properties of a new copper(II) one-dimensional coordination polymer based on bridging N,N'-bis(2-hydroxybenzylidene)-2,2-dimethylpropane-1,3-diamine and dicyanamide ligands

The design and synthesis of polymeric coordination compounds of 3d transition metals are of great interest in the search for functional materials. The coordination chemistry of the copper(II) ion is of interest currently due to potential applications in the areas of molecular biology and magnetochemistry. A novel coordination polymer of Cu(II) with bridging N,N'-bis(2-hydroxyphenyl)-2,2-dimethylpropane-1,3-diamine (H2L-DM) and dicyanamide (dca) ligands, catena-poly[[[μ2-2,2-dimethyl-N,N'-bis(2-oxidobenzylidene)propane-1,3-diamine-1:2κ(6)O,N,N',O':O,O']dicopper(II)]-di-μ-dicyanamido-1:2'κ(2)N(1):N(5);2:1'κ(2)N(1):N(5)], [Cu2(C19H20N2O2)(C2N3)2]n, has been synthesized and characterized by CHN elemental analysis, IR spectroscopy, thermal analysis and X-ray single-crystal diffraction analysis. Structural studies show that the Cu(II) centres in the dimeric asymmetric unit adopt distorted square-pyramidal geometries, as confirmed by the Addison parameter (τ) values. The chelating characteristics of the L-DM(2-) ligand results in the formation of a Cu(II) dimer with a double phenolate bridge in the asymmetric unit. In the crystal, the dimeric units are further linked to adjacent dimeric units through μ1,5-dca bridges to produce one-dimensional polymeric chains.