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Tailored reaction of Schiff base ligands with palladium(II) chloride and imidazole afford three complexes of formula [Pd(II)(L)(imdz)2]Cl, which are L = 2-((E)-(p-lylimino)methyl)-6-methoxyphenol (complex 1), 2-methoxy- -6-((E)-(phenylimine)methyl)phenol (complex 2) and 2-((E)-(4-chlorophenylimino) methyl)-6-methoxyphenol (complex 3). Compounds were characterized with elemental analysis, molar conductance, electronic spectroscopy, ESI-MS, FT-IR, TGA, 1H-NMR and 13C-NMR. Molecular structure and different quantum chemical parameters were calculated using the B3LYP basis set of density functional theory with the standard 6-311+G (d, 2p) level. The catalytic potential of 1-3 was examined over Heck-Mizoroki reaction and found in order of 1 > 2 > 3.

The Schiff base ligand, namely (7E)-N-benzylidene-2-styrylbenzenamine- 1,2-diamine-2,4-dihydroxy-phenol (L), was synthesized by condensation of 2,4-dihydroxybenzaldehyde with o-phenylenediamine. The reaction of the ligand with Fe(III), Co(II) and Ni(II) salts in an 1:1 ratio yielded three complexes (1–3). Different analytical tools, like elemental analysis, ESI-MS, UV–Vis, FT-IR, NMR and EPR spectroscopy, then molar conductivity and magnetic susceptibility spectra, were used to elucidate the structure of the ligand and complexes. Density functional theory calculation at the B3LYP/3- -211G++/LANL2DZ level of the theory has been carried out to optimize the geometry of the ligand and complexes. The tetradentate ligand has coordinated to metals through ONNO donors affording octahedral geometry. Complexes were studied for their oxygen-binding activity and free radical scavenging activities. Complexes 1 and 2, which contain Fe(IIl) and Co(II), displayed reversible oxygen binding activity. On the other hand, complex 3 fails to show oxygen binding. The order of antioxidant activity is: 3 > 1 > 2 > L.

Drug resistance in pathogens is a growing global health problem. The development of new drugs is a risky, time-consuming, and expensive process, since only a few got final approval. Organometallic compounds attracted attention due to their promising anticancer activities. In this study, four cyclometallates containing ruthenium and rhodium ions were synthesized from two phenolic azo ligands. These molecules were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility, FT-IR, mass, electronic,1H,13C{1H}, and31P{1H} NMR spectral studies. The general formula for the complexes istrans-[M(PPh3)2(Cl)(L)], where M = Rh or Ru, PPh3 = triphenylphosphine, and L = phenolic azo ligand. All the complexes possess prominent antibacterial activity againstEscherichia coliandMycobacterium tuberculosisas compared to market drugs. The interactions of rhodium derivatives with plasma–protein were also studied. Cyclometalation of a pendant aromatic ring is an example of C–H bond activation. Organometallic compounds were biologically potent and may be helpful for pharmaceutical industries for biological targets. [ABSTRACT FROM PUBLISHER]