Mononuclear and heterometallic dinuclear, trinuclear and dimer-of-dinuclear complexes derived from single- and double-compartment Schiff base ligands having a less utilized diamine

A combined experimental and computational study on supramolecular assemblies in hetero-tetranuclear nickel(ii)-cadmium(ii) complexes with N2O4-donor compartmental Schiff bases

Two new hetero-tetranuclear nickel(ii)/cadmium(ii) complexes, a cubane [(CH₃CO₂)₂Ni₂(L¹)₂Cd₂(NCS)₂] (1) and a linear tetramer [(DMSO)₂NiL²Cd(NCS)(μ_1,3-SCN)Ni(DMSO)L²Cd(NCS)₂] (2) {where H₂L¹ = N,N'-bis(3-methoxysalicylidene)propane-1,3-diamine and H₂L² = N,N'-bis(3-ethoxysalicylidene)propane-1,3-diamine are potential octadentate compartmental Schiff bases}, were synthesized and characterized. The structures of both complexes were confirmed by single crystal X-ray diffraction studies. Complex 1 contained a Ni₂Cd₂O₄ cubane core, whereas complex 2 featured an end-to-end thiocyanate-bridged tetranuclear moiety. Furthermore, complex 1 showed C-HH-C interactions, whereas a unique Sπ interaction was observed in complex 2. Theoretical studies were performed using several computational tools such as NBO and AIM analyses. Both complexes showed photoluminescence in DMSO medium at room temperature upon irradiation with ultraviolet light. The lifetimes of the excited states were ∼27 ns.

Theoretical and experimental investigation of anticancer activities of an acyclic and symmetrical compartmental Schiff base ligand and its Co(ii), Cu(ii) and Zn(ii) complexes

A compartmental Schiff base ligand, 2,2′-((((((2-hydroxypropane-1,3-diyl)bis(oxy))bis(2,1-phenylene))bis(methylene))bis(azanylylidene))bis(methanylylidene))bis(4-bromophenol) (H₃L^Br) and its complexes with cobalt(ii), copper(ii) and zinc(ii) including, [Co(HL^Br)] (1), [Cu₂(L^Br)(μ-1,3-OAc)]·MeOH (2) and [Zn(HL^Br)] (3) were prepared using template synthesis and characterised by elemental analysis, FT-IR and ¹H NMR spectroscopies and single-crystal X-ray diffraction. In the structure of complexes 1 and 3 the metal atom has a MN₂O₂ environment with tetrahedral geometry while complex 2 has a binuclear structure with a MNO₄ environment and square planar geometry around the copper atom. The ability of all compounds to interact with the nine biomacromolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS and Top II) are investigated by docking calculations. For examination of the docking results, the in vitro activities of eight compounds against the human leukemia cell line K562 was investigated by evaluation of IC₅₀ values and mode of cell death (apoptosis).

A compartmental Schiff base ligand and its copper, cobalt and zinc complexes were prepared. The in vitro activities of all compounds against the human leukemia cell line K562 were investigated along with docking and DFT studies.

Exploration of unconventional π–hole and C–H⋯H–C types of supramolecular interactions in a trinuclear Cd(ii) and a heteronuclear Cd(ii)–Ni(ii) complex and experimental evidence for preferential site selection of the ligand by 3d and 4d metal ions

We report the synthesis of a trinuclear cadmium(ii) (1) and a di(phenoxido)-bridged dinuclear cadmium(ii)–nickel(ii) (2) complex derived from a bicompartmental (N₂O₄) Schiff base ligand.