An-Najah Staff

A novel series of Pd(II) complexes derived from 2-thiophenecarboxaldehyde and 1,8-diaminonaphthalene has been synthesized and characterized by various physico-chemical and spectroscopic techniques viz., elemental analyses, IR, UV-Vis, 1H and 13C NMR spectroscopy, and ESI-mass spectrometry. The structure of ligand, 2-(2-thienyl)-2,3-dihydro-1H-perimidine has been ascertained on the basis of single crystal X-Ray diffraction. All Pd(II) complexes together with the corresponding ligand have been evaluated for their ability to suppress the in vitro growth of microbes, E. coli, S. aureus, P. aeruginosa, Citrobacter sp., B. subtilis and S. acidaminiphila and results show that Pd(II) complexes have more significant antimicrobial activity than their corresponding ligand. Fluorescence spectroscopic measurements clearly support that both of the Pd(II) complexes show significant DNA binding with calf thymus DNA.

The novel (ether-phosphine)palladium(II) complexes such as Cl2Pd(h1-Ph2PCH2CH2OCH3)2 2, [Pd(h2- Ph2PCH2CH2OCH3)2]+22BF4 - 3 and [Pd(h1-Ph2PCH2CH2OCH3)2diamine]+22BF4 - 4L1-4L4 (Scheme1) have been obtained by reaction of [PdCl2(NCCH3)2 or PdCl2(NCPh)2] with two equimolar amounts of Ph2PCH2CH2OCH3 to produce complex 2. The dicationic complex 3 was produced by treating complex 2 with slightly excess amount of two equivalent of AgBF4 in CH2Cl2. Due to the hemilabile character, the (ether)oxygen atom of the ether-phosphine ligand immediately occupied the vacant coordination sites which created by chloride abstracted agent (AgBF4) and avoided complex decomposition. Several diamines were served as an incoming ligands, the (ether)oxygen atom can easily be displaced by these diamines to prepare complexes 4L1-4L4 in very good yields. These complexes were characterized by NMR, IR, and mass spectroscopy as well as by elemental analyses. Because of the ring contribution of the chemical shift the dissociation and association (open and close mechanism) of the weak donor can be studied by 31P{1H} NMR spectroscopy at room temperature.

We have reported the synthesis of a novel salen ligand and its mononuclear Pd–salen complexes derived from 2-{[2-hydroxy-3-{[(E)-(2-hydroxyphenyl)methylidene]amino}propyl)imino]methyl}phenol. The newly synthesized and isolated Pd(II) complexes have been identified and fully characterized by various physico-chemical studies viz., elemental analyses, IR, UV-Vis, 1H, 13C NMR spectroscopy, electron spray ionization mass spectrometry (ESI-MS) and TGA/DTA studies. The molecular structure of the salen ligand has been ascertained by single-crystal XRD and it is coordinated to Pd(II) ion through two nitrogen and two oxygen atoms. The UV-Vis data clearly suggest a square-planar environment around both the Pd(II) ions. The DNA binding studies of the synthesized compounds has been investigated by electron spectroscopy and fluorescence measurements. The results suggest that Pd(II) complexes bind to DNA strongly as compared to the free ligand. The free salen ligand and its Pd(II) complexes have also been tested against human hepatoma cancer cell line (Huh7) and results manifested exceptional anti-proliferative effects of the Pd(II) complexes. The anti-proliferative activity of Pd(II) complexes has been modulated by specific regulatory genes.

Two novel and neutral bidentate Palladium(II) complexes of the type, [PdX2(dpme)] (X = Cl 1, OAc 2], have been synthesized from 1,1-bis(diphenylphosphinomethyl)ethene (dpme) ligand and characterized on the basis of elemental analyses, infrared, FAB-MS and 1H-, 13C-, and 31P-NMR spectroscopy. The structure of 1 has been ascertained by single crystal X-ray crystallography and shows cis configuration in a square planar structure while the structural behavior of the dpme ligand through the formation of these complexes has been monitored by 31P{1H} NMR and IR spectra. These Pd(II) complexes have shown a very significant catalytic role in Heck reaction giving high yield under mild condition.