Copper(I) halide complexes of 2,2,5,5-tetramethyl-imidazolidine-4-thione: Synthesis, structures, luminescence, thermal stability and interaction with DNA.

Five neutral mononuclear copper(I) halide complexes containing 2,2,5,5-tetramethylimidazolidine-4-thione (tmimdtH) and triphenylphosphane (PPh3) or tri-o-tolylphosphane (totp) have been prepared and structurally characterized by X-ray single-crystal analysis. The complexes containing PPh3 adopt the usual distorted tetrahedral geometry, while the presence of the bulkier totp forces the formation of three-coordinated trigonal planar species. The interaction of the compounds with calf-thymus DNA was monitored directly via UV-vis spectroscopy, DNA-viscosity measurements and indirectly via its competition with ethidium bromide for DNA studied by fluorescence emission spectroscopy. Intercalation was revealed as the most possible mode of binding. Furthermore, luminescent properties and thermal stabilities of the complexes were investigated.

Silver(I) complexes of N-methylbenzothiazole-2-thione: synthesis, structures and antibacterial activity.

Three silver(I) complexes containing N-methylbenzothiazole-2-thione (mbtt) have been prepared and structurally characterized by X-ray single-crystal analysis. Silver(I) nitrate, and silver(I) triflate react with mbtt to give homoleptic complexes of formula [(mbtt)2Ag(µ-mbtt)2Ag(mbtt)2](NO3)2 (1) and [Ag(mbtt)3](CF3SO3) (2) respectively, while silver(I) chloride gives the binuclear halide-bridged [(mbtt)2Ag(µ2-Cl)2Ag(mbtt)2] (3). In the binuclear complex 1 the two metal ions, separated by 3.73 Å from each other, are doubly bridged by the exocyclic S-atoms of two mbtt ligands, with the tetrahedral environment around each silver ion being completed by the S-atoms of two terminally bonded mbtt units. Compound 2 is mononuclear with the metal ion surrounded by the exocyclic S-atoms of three mbtt ligands in a nearly ideal trigonal planar arrangement. The new complexes showed significant in vitro antibacterial activity against certain Gram-positive and Gram-negative bacterial strains.

Copper(I) halide complexes of 5-carbethoxy-2-thiouracil: synthesis, structure and in vitro cytotoxicity.

5-Carbethoxy-2-thiouracil (eitotH2) reacts with copper(I) halides CuX (X = Cl, Br, I) to give dinuclear complexes of the formula [CuX(eitotH2)2]2 while mononuclear mixed-ligand complexes of the formula [CuX(PPh3)2(eitotH2)] result when the reactions are performed in the presence of two equivalents of triphenylphosphine (PPh3). The molecular structures of representative compounds from each of the above types of complexes, namely [CuI(eitotH2)2]2, [CuCl(PPh3)2(eitotH2)] and [CuBr(PPh3)2(eitotH2)] have been established by single-crystal X-ray diffraction. The new copper(I) complexes were evaluated for in vitro antitumor properties against two tumor cell lines, A549 (human pulmonary carcinoma cell line) and HeLa (human epithelial carcinoma cell line) and one normal immortalized cell line MRC5 (human fetal lung fibroblast). The mixed-ligand complexes possessing triphenylphosphine were found to be highly cytotoxic in contrast to the phosphine-free ones which inhibited cell proliferation only in relatively high concentrations.

Copper(I) halide complexes of N-methylbenzothiazole-2-thione: synthesis, structure, luminescence, antibacterial activity and interaction with DNA.

The reactions of copper(I) halides, CuX (X=Cl, Br, I) with N-methylbenzothiazole-2-thione (mbtt), independent of the molar ration chosen (1:2 or 1:3), led to the formation of dinuclear complexes of the formula [CuX(mbtt)2]2, whereas the reactions of CuX and mbtt in the presence of two equivalents of triphenylphosphine (PPh3) afforded mononuclear mixed-ligand complexes of the formula [CuX(PPh3)2(mbtt)]. The molecular structure of a representative compound from each of the two above types of complexes, namely [CuCl(mbtt)2]2 and [CuI(PPh3)2(mbtt)] have been established by single-crystal X-ray diffraction. The new complexes are strongly emissive both in the solid state and in solution. The complexes were also screened for antibacterial activity and their ability to interact with native calf thymus DNA (CT-DNA) in vitro. Both types of complexes showed significant activities against all the bacteria tested as compared to that of standard antibiotic ampicillin, however, the three mixed-ligand complexes including triphenylphosphane as ligand exhibited perceptibly stronger antibacterial activity than the three homoleptic ones possessing only the mbtt ligand. DNA electrophoretic mobility experiments showed that all complexes bind to CT-ds DNA resulting in high molecular weight complexes ending in DNA degradation.

Structural and electronic properties of luminescent copper(I) halide complexes of bis[2-(diphenylphosphano)phenyl] ether (DPEphos). Crystal structure of [CuCl(DPEphos)(dmpymtH].

Heteroleptic copper(I) halide complexes containing the bis[2-(diphenylphosphano)phenyl]ether (DPEphos) ligand and the heterocyclic thioamides pyridine-2(1H)-thione (py2SH), pyrimidine-2(1H)-thione (pymtH) or 4,6-dimethylpyrimidine-2(1H)-thione (dmpymtH) have been synthesized and characterized by (1)H-NMR, IR spectroscopy, elemental analyses and melting point determinations. The complexes can be readily obtained by the addition of the thione ligand to a CuX-diphosphane adduct in dichloromethane-ethanol solution. The molecular structure of [CuCl(DPEphos)(dmpymtH)] complex has been established by single-crystal X-ray diffraction. The structure features a tetrahedral copper(I) center with two phosphorus atoms from the chelating diphos ligand, one halogen atom and the exocyclic sulfur atom of the heterocyclic thioamide unit. The complexes are strongly emissive in the solid state at ambient temperature. DFT and TD-DFT calculations were employed to study the structural, electronic and photophysical properties of the novel complexes. Electronic absorption spectra show two broad bands in the regions 275-290 and 380-398 nm of mixed MLCT/IL character. Intense blue-green emission is observed in the region 500-558 nm for complexes having py2SH or dmpymtH thione ligands. The emitting first triplet excited state, T(1) is mainly localized on the thione ligand.