Synthesis, Spectroscopic Characterization and Antibacterial Assessment of Zirconium(II) and Palladium(II) Complexes of Tetracycline-Salicylaldehyde Mixed Ligand

Abstract

Zirconium(II) and palladium(II) mixed ligand metal complexes were synthesized by using an equimolar mixture of tetracycline (Tc) as primary ligand and salicylaldehyde as secondary ligand. The metal complexes were characterized by physico-chemical and spectroscopic techniques like CHN analysis, surface tension, pH, conductivity and melting point measurements. The spectroscopic characterization technique includes IR, (1H & 13C) NMR, UV/visible and Mass spectrometry methods. The SEM technique determines the surface morphology of the complexes. The thermal and kinetic stability of the complexes was obtained from TGA/DTA curves from which the parameters like E*, ΔH*, ΔS* and ΔG* have been calculated by using the Coats-Redfern equation. Molecular modeling gives a geometry of the complex which was obtained from Chem 3D Pro. 12.0 software program. The metal complexes of Zr-TcSal and Pd-TcSal have coordinated with tetrahedral and square planar geometry, respectively. The antibacterial susceptibility study of the synthesized metal complexes was done by Kirby-Bauer paper disc diffusion techniques on S. aureus, E. coli and P. aeruginosa clinical pathogens

Plausible PEPPSI catalysts for direct C–H functionalization of five-membered heterocyclic bioactive motifs: synthesis, spectral, X-ray crystallographic characterizations and catalytic activity

“…1) has a distorted square planar form, with Pd(01)-C(008) 1.957(4) Å, Pd(01)-N(006) 2.100(4) Å, Pd(01)-Br(02) 2.4471 (7) 32 the Pd-C(carbene) bond length is considerably shorter than in those species (2.012(4), 2.039(7) Å), presumably because here the bound C-atom is trans to a relatively weak pyridine-N donor. In fact, the Pd-C bond length is very close to that observed in a true PEPPSI complex of PdCl 2 (1.964(3) Å, for example 90 ). The large carbene-N substituents appear to effectively block the axial sites on Pd, though with no indication of signicant anagostic Pd/H interactions.…”

Palladium(II) Complexes of Substituted Salicylaldehydes: Synthesis, Characterization and Investigation of Their Biological Profile

“…Since increased bacterial resistance to current antibiotics brings an urgent need for the discovery of new complexes with antibacterial properties, in recent years, many efforts Since increased bacterial resistance to current antibiotics brings an urgent need for the discovery of new complexes with antibacterial properties, in recent years, many efforts towards the development of new palladium(II) drugs were shown to direct to a different target: multi-resistant bacterial strains, [6,7]. Recent examples of palladium complexes bearing antimicrobial properties include mixed-ligand Pd(II) complexes of tetracycline and salicylaldehyde [8], Pd(II) complexes bearing azomethine chelates [9], palladium(II) complexes with Schiff bases [10], N-heterocyclic carbene-Pd(II)-triphenylophosphine complexes [11], as well as a palladium(II) complex with ibuprofen [6].…”