Shafqat Nadeem

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

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]Cl2 or [Pd(L)4]Cl2 where 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 and 13C NMR) methods. An upfield shift in the >C═S resonance of thiones in 13C NMR and downfield shift in N–H or aromatic proton resonances in 1H 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.

Tetrakis(thiourea-κS)palladium(II) dithio­cyanate

The title compound, [Pd(CH4N2S)4](SCN)2, consists of complex [Pd(TU)4]2+ [TU = thiourea, SC(NH2)2] cations and thiocyanate counter-anions. The PdII cation is situated on an inversion centre and exhibits an almost square-planar coordination by the S atoms of the TU ligands. The complex cations are connected through the thiocyanate ions via N—H⋯N [2.922 (3)–3.056 (3) Å] and N—H⋯S [3.369 (2)–3.645 (2) Å] hydrogen bonds.

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

Abstract The paper emphasizes on the synthesis of Palladium(II) iodide complexes containing based ligands. The new compounds of general formulae [Pd(L)4]I2 where L = Thiourea (Tu), Methylthiourea (Metu), Dimethylthiourea (Dmtu), Tetramethylthiourea (Tmtu), Imidazolidine-2-thione (Imt), Mercaptopyridine (Mpy), Mercaptopyrimidine (Mpm), and Thionicotinamide (Tna) were prepared simply by reacting K2[PdCl4] with the corresponding thioamides in 1:2 M ratio and then with 2 equivalents Potassium iodide. The complexes were characterized by elemental analysis and spectroscopic techniques (IR, 1H and 13C NMR). All the synthesized complexes were screened for antibacterial activity and some of compounds have shown good activities against both gram positive and gram negative bacteria. POM analyses reveal that the compounds are only slightly toxic and present a potential for antibacterial activity. Moreover, they have 16–23% drug score which is an important parameter for the compound possessing the drug properties.

3-Carbamothioylpyridinium iodide

In the crystal of the title salt, C6H7N2S+·I−, inversion-related cations form an R 2 2(8) dimer linked by a pair of N—H⋯S hydrogen bonds. Pairs of iodide anions are located between adjacent cation dimers and are linked to them by way of N—H⋯I hydrogen bonds. This results in zigzag chains propagating in [001] lying parallel to the bc plane.

SYNTHESIS, CRYSTAL STRUCTURE, AND ANTIMICROBIAL STUDIES OF TRANS-[PD(PPH3)2(IMIDAZOLIDINE-2-THIONE)2]CL2 · 3.5H2O

The palladium(II) complex, [Pd(PPh3)2(Imt)2]Cl2 · 3.5H2O (I) (Imt = imidazolidine-2-thione), has been synthesized and characterized by IR, NMR, and X-ray crystallography. An upfield shift in the >C=S resonance of Imt in the 13C NMR spectrum and a downfield shift in the N-H resonance in 1H NMR are consistent with the sulfur coordination of Imt to palladium(II). In the crystal structure of I, the central palladium atom is coordinated to two thione sulfur atoms of Imt and to two phosphorus atoms possessing a square-planar environment with the average cis and trans bond angles of 89.60° and 167.31°, respectively. The title complex was screened for antimicrobial effects, and the results showed that it exhibits moderate activities against gram-negative bacteria (E. coli, P. aeruginosa). The complexes also exhibited significant activities against yeast (C. albicans, S. serevisaiae).

Synthesis, Spectral Characterization, In Vitro Antibacterial Evaluation and POM Analyses of Palladium(II) Thiocyanate Complexes of Thioamides

Palladium(II) thiocyanate complexes of general formula, [PdL4](SCN)2, where L = thiourea (Tu), N-methylthiourea (Metu), N,N-dimethylthiourea (Dmtu), tetramethylthiourea (Tmtu), imidazolidine-2-thione (Imt) and thionicotinamide (Tna) were prepared by the reaction of K2[PdCl4] with thioamides followed by the addition of Potassium thiocyanate in 1:2:2 molar ratio. The complexes were characterized by elemental analysis, and spectroscopic techniques (IR, 1H and 13C NMR), and were screened for antibacterial activities against four strains of bacteria {Staphylococcus aureus (ATCC 25923), Bacillus subtilis (DSM 3256), Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 10197)}. Some of the compounds exhibited signifiacnt antibacterial activity even higher than the standards showing the potential for their use as potent antibacterial agents. POM analyses reveal that the compounds are slightly toxic. Moreover, they have 8 ~ 12 % drug score, which is an important parameter for a compound possessing the drug properties.

Synthesis, Characterization, and DFT Investigation of a Zinc(II)–Silver(I) Bimetallic Complex, [Zn(Dmen)2{Ag(CN)2}2][Zn(Dmen)2(H2O)2]{Ag(CN)2}2 (Dmen = N,N′-Dimethylethylenediamine)

A cyanido bridged Zn(II)-Ag(I) bimetallic complex (I) has been prepared and characterized by IR spectroscopy, thermal analysis, X-ray crystallography (CIF file CCDC no. 884016) and DFT calculations. Thermal analysis shows that the composition of the compound is consistent with the proposed stoichiometry, i.e., [Zn(diamine)2{Ag(CN)2}2] · H2O. The crystal structure of complex I consists of two independent molecules; a trinuclear molecule, [Zn(Dmen)2{Ag(CN)2}2] and an ionic species, [Zn(Dmen)2-(H2O)2]{Ag(CN)2}2; the overall formula being [Zn(Dmen)2{Ag(CN)2}2][Zn(Dmen)2(H2O)2]{Ag(CN)2}2 (I) (Dmen = N,N′-dimethylethylenediamine). The structures of I and two of its analogues, [Zn(Dmen)2{Ag(CN)2}2]2 · 2H2O (II) and {[Zn(Dmen)2{Ag(CN)2}][Ag(CN)2]}2 · 2H2O (III) were predicted by DFT calculations. The DFT results reveal that the structure I is more stable in comparison to the calculated structures, II and III. The X-ray structure of I shows that the complex is also stabilized by the argentophilic interactions. The Ag···Ag interaction energy calculated at the MP2 level of theory is –4.02 kcal mol–1.