Synthesis, spectral characterization and antibacterial studies of palladium(II) complexes of heterocyclic thiones

Abstract

Reactions of K2[PdCl4] with heterocyclic thiones in molar ratios of 1:2 and 1:4 in water-methanol medium yielded the palladium(II) complexes with the general formula of either [Pd(L)Cl2], [Pd(L)2]Cl2or [Pd(L)4]Cl2where L ═ Imidazolidine-2-thione (Imt), 2-Mercaptopyridine (Mpy), 2-Mercaptopyrimidine (Mpm), 6-Mercaptopurine (6-Mp) and Thionicotinamide (Tna). The complexes were characterized by elemental analysis and spectroscopic (IR,1H and13C NMR) methods. An upfield shift in the >C═S resonance of thiones in13C NMR and downfield shift in N–H or aromatic proton resonances in1H NMR are consistent with the sulfur coordination to palladium(II). The complexes were screened for antibacterial activity, and the results showed that the complexes exhibited moderate activities as compared to that of a standard drug.

Synthesis, characterization and antibacterial activity of palladium(II) bromide complexes of thioamides; X-ray structure of [Pd(tetramethylthiourea)4]Br2

“…C electron density producing a partial double bond character in the C-N bond, as observed in the other metal complexes of thiourea [7-10, 23, 24, 44]. The shifts are comparable to other palladium(II) complexes of thiones [23,24,45]. As the shift difference may be related to the strength of the metal-sulfur bond, Table 4 suggests that the Mpy complex with the most significant shift in the C=S resonance would be the most stable.…”

“…However, in all known cases, the central palladium atom possesses a square-planar geometry. Considering the importance of these complexes from structural and bioinorganic chemistry points of view, we have previously reported the spectroscopic and structural characterization of several palladium(II) chloride complexes of thiones [22][23][24]. The present report describes the spectroscopic characterization and antibacterial properties of palladium(II) bromide complexes of thiones.…”

Synthesis, spectral characterization and in vitro antibacterial evaluation and Petra/Osiris/Molinspiration analyses of new Palladium(II) iodide complexes with thioamides

“…Metal complexes with thioamides are capable of inhibiting bacterial growth and activity by interfering with the metabolic process in the bacteria. [1][2][3]14,20,33,36,38,41,42 In the present work, we have synthesized thioamides Palladium(II) iodide complexes and their. Antibacterial activities have been determined against four strains of bacteria S. aureus (ATCC 25923), B. subtilis (DSM 3256), E. coli (ATCC 25922), and P. aeruginosa (ATCC 10197).…”

“…The antibacterial activity of complexes may be attributed to their inhibition in the metabolic pathway which alter the replication of DNA. Moreover the Palladium(II) complexes have the ability to form hydrogen bonding with the constituents of cell and cell wall 43 or direct interaction with membrane, enzyme and proteins. The ligands have the capability to carry metal to the target (DNA) and allow it to interact with it.…”

“…The coordination and structural chemistry of Palladium based complexes with donor atoms, especially sulfur containing ligands have been extensively studied. [1][2][3][4][5] Palladium(II) complexes with heterocyclic thiones and thioureas as ligands showing a square-planar geometry have promising bio-relevant activities, particularly Mercaptopyrimidine, 6-Mercaptopurines, Imidazolidine-2-thione, and Diazinane-2-thione and their complexes with Palladium(II) are known to have antitumor activities. [6][7][8][9][10][11][12][13][14][15][16] In view of great potential, several complexes of thioamides with Au(I), Ag(I), Cu(I) Zn(II) Mo(II), Cd(II) Pd (II) and Hg(II) have been widely studied.…”