Mononuclear, oligonuclear and polynuclear metal coordination compounds with 1,2,4-triazole derivatives as ligands

Complexes of heterocyclic thione donors

The secular determinants obtained in the previous paper are solved for the energy levels which are important in the absorption spectra of the normal complex ions, leaving the crystalline field strength as a parameter. The values of B and C (Racah's parameters) there needed are determined from the observed spectra of free ions or in some cases by extrapolation. The f -values of the transitions which connect the energy levels calculated are estimated and compared with the observed intensities. The difference of the spectral width among absorption bands and lines is also considered using the energy diagram obtained. Following the assignments determined by the above considerations, the calculated positions of lines and bands are rather in good agreement with the experimental data in divalent ions [MX 6 ] 2+ (M=Cr, Mn, Fe, Co, Ni), when we adjust the crystalline field parameter D q suitably. In trivalent ions [MX 6 ] 3+ (M=Ti, V, Cr, Mn, Fe), it is necessary besides the adjustment of D q to use smaller values ...

On the absorption spectra of complex ions. II

Coordination compounds of copper, nickel and iron with Schiff bases derived from hydroxynaphthaldehydes and salicylaldehydes

At present, cisplatin (cis-diamminodichloroplatinum(II)) is one of the most largely employed anticancer drugs as it is effective in the treatment of 70-90% of testicular and, in combination with other drugs, of ovarian, small cell lung, bladder, brain, and breast tumors. Anyway, despite its high effectiveness, it exhibits some clinical problems related to its use in the curative therapy, such as a severe normal tissue toxicity (in particular, nephrotoxicity) and the frequent occurrence of initial and acquired resistance to the treatment. To obtain compounds with superior chemotherapeutic index in terms of increased bioavailability, higher cytotoxicity, and lower side effects than cisplatin, we report here on some gold(I) and gold(III) complexes with dithiocarbamate ligands (DMDT = N,N-dimethyldithiocarbamate; DMDTM = S-methyl-N,N-dimethyldithiocarbamate; ESDT = ethylsarcosinedithiocarbamate), which have been synthesized, purified, and characterized by means of elemental analyses, conductivity measurements, mono- and bidimensional NMR, FT-IR, and UV-vis spectroscopy, and thermal analyses. Moreover, the electrochemical properties of the designed compounds have been studied through cyclic voltammetry. All the synthesized gold complexes have been tested for their in vitro cytotoxic activity. Remarkably, most of them, in particular gold(III) derivatives of N,N-dimethyldithiocarbamate and ethylsarcosinedithiocarbamate, have been proved to be much more cytotoxic in vitro than cisplatin, with IC50 values about 1- to 4-fold lower than that of the reference drug, even toward human tumor cell lines intrinsically resistant to cisplatin itself. Moreover, they appeared to be much more cytotoxic also on the cisplatin-resistant cell lines, with activity levels comparable to those on the corresponding cisplatin-sensitive cell lines, ruling out the occurrence of cross-resistance phenomena and supporting the hypothesis of a different antitumor activity mechanism of action.

Gold dithiocarbamate derivatives as potential antineoplastic agents: design, spectroscopic properties, and in vitro antitumor activity.

Synthesis and characterization of ruthenium dithiocarbamate complexes

A new series of manganese(III), cobalt(II), nickel(II), zinc(II), cadmium(II) and mercury(II) complexes with monomethylsubstituted dithiocarbamates as ligands has been synthesized and studied Their structures are discussed in relation to their spectroscopic, magnetic and thermal properties The dithio-ligands exhibit bidentate behaviour acting as S,S′donors in all the complexes In the far ir region particular attention is paid to a comparison of the spectra of the octahedral complexes with those of the other metal derivatives (1∶2 metal to ligand molar ratio) The esr spectra are indicative of aD2h symmetry in the cobalt(II) complexes

Transition metal complexes with 2-methyl-, 3-methyl-, and 4-methyl-piperidine dithiocarbamate as ligands

Transition metal complexes of piperazinedithiocarbamate

The preparation and characterization of some cobalt(II), nickel(II) and copper(II) complexes with 7-chloro-2-methylamino-5-phenyl-3H-1, 4-benzodiazepin-4-oxide and 1, 3-dihydro-7-nitro-5-phenyl-2H-1, 4-benzodiazepin-2-one are reported. The complexes have been studied by means of magnetic susceptibility measurements, infrared and far infrared spectra, electronic spectra and conductivity measurements. Assignments for the metal-ligand and metal-halide bands have also been made. The evidence suggests that the cobalt(II) and nickel(II) complexes have a pseudotetrahedral symmetry, whereas the copper(II) complexes are octahedral.

Carlo Preti

Papers

Synthesis and characterization of ruthenium dithiocarbamate complexes

Transition metal complexes with 2-methyl-, 3-methyl-, and 4-methyl-piperidine dithiocarbamate as ligands

Transition metal complexes of piperazinedithiocarbamate

The syntheses and properties of cobalt(ii), nickel(ii) and copper(ii) complexes with some 1,4-benzodiazepines

Synthesis and spectroscopic characterization of arsenic(III), antimony(III), bismuth(III), tin(II) and lead(II) dithiocarbamate adducts