Synthesis, X-ray characterization, DFT calculations and Hirshfeld surface analysis of Zn(ii) and Cd(ii) complexes based on isonicotinoylhydrazone ligand

Abstract

In this manuscript we report the synthesis and X-ray characterization of four ZnIJII) complexes and three CdIJII) complexes with an asymmetrical hydrazone-pyridine based ligand {HL = 2-acetyl-pyridylisonicotinoylhydrazone (HAPIH)} 7). The Schiff base acts as a tridentate N 2 Odonor ligand through the oxygen, the imine and pyridine nitrogen atoms in all the complexes. In most complexes, the ligand is observed to coordinate as a zwitterion since the proton in the hydrazine group (N-NH-CO) shifted to the uncoordinated pyridine ring, except in 7. On the other hand, in 5 the ligand acts as a negatively charged species and is bound to the cadmium center in the enolic form (N-NC-O − ). In complexes 2-4, 6 and 7, the coordination geometry around each metal center is distorted trigonal bipyramidal, with the coordination sphere of the metal completed by two halide or NCS anions. On the other hand, in homoleptic complexes 1 and 5, the metal, chelated by two tridentate Schiff base ligands, exhibits an octahedral geometry. In the crystal packing of all compounds, the pyridine rings favour π-π interactions among the symmetry related complexes. The noncovalent interactions among the complexes have been analyzed using Hirshfeld surface analysis and DFT calculations using Grimme's D3 dispersion correction to properly describe the π-π interactions.

Five‐coordinate dinuclar cobalt (II), copper (II), zinc (II) and cadmium (II) complexes with 4‐bromo‐N‐(2‐pyridinylmethylene)benzenamine: Synthesis, characterisation and methyl methacrylate polymerization

“…The bond lengths of M–N pyridine (M = Co, Cu, Zn, and Cd) and M–N imine in [(bpma)M(μ – X)X] 2 (M = Co, Cu and Zn, X = Cl; M = Cd, X = Br) lie in 2.064(4) – 2.2886(2) Å and 2.038(4) – 2.4160(2) Å range, similar to the M–N bond lengths of trigonal bipyramidal imine M (II) complexes . The bond length of M–N imine increased by approximately 0.015–0.200 Å, ranging in size from ([ (bpma)Cu(μ – Cl)Cl] 2 ) < ([ (bpma)Co(μ – Cl)Cl] 2 ) < ([ (bpma)Zn(μ – Cl)Cl] 2 ) < ( [(bpma)Cd(μ – Br)Br] 2 ).…”

Targeted synthesis of cadmium(ii) Schiff base complexes towards corrosion inhibition on mild steel

“…The cadmium atom is in the distorted octahedral environment and coordinated by two tridentate Schiff base ligands (L 1 ) ( (Table 2), quite similar to those which have been reported earlier. 44 The two pyridine rings in the complex cation are approximately perpendicular to each other, making a dihedral angle of 88.57 . The perchlorate anions are linked to the complex cation through C-H/O hydrogen bonds and these hydrogen bonds are mainly responsible for the formation of a supramolecular spiral chain-like structures (Fig.…”

“…The octahedral geometry of (Table 2), similar to earlier report. 44 Each dimeric unit is linked with each other via C4-H4/N3 hydrogen bonding (Fig. 2) to make a 1D chain like structure along c-axis (Fig.…”

Crystal structure, characterization, Hirshfeld surface analysis and DFT studies of two [propane 3-bromo-1-(triphenyl phosphonium)] cations containing bromide (I) and tribromide (II) anions: The anion (II) as a new brominating agent for unsaturated compounds

“…The Hirshfeld surfaces and 2D fingerprint plots, calculated using Crystal Explorer 3.1 from the single crystal structures, were used for visualizing, exploring and quantifying intermolecular interactions [29][30][31] on the surface of molecule in the crystal lattice for both compounds.…”