Synthesis, Structural Characterization, and Biological Evaluation of Oxorhenium(V) Complexes with a Novel Type of Thiosemicarbazones Derived from N-[N′,N′-Dialkylamino(thiocarbonyl)]benzimidoyl Chlorides

Abstract

Reactions of N-[N',N'-diethylamino(thiocarbonyl)]benzimidoyl chloride with 4,4-dialkylthiosemicarbazides give a novel class of thiosemicarbazides/thiosemicarbazones, H(2)L, which causes a remarkable reduction of cell growth in in vitro experiments. These strong antiproliferative effects are also observed for oxorhenium(V) complexes of the general composition [ReOCl(L)], which are formed by reactions of the potentially tridentate ligands with (NBu(4))[ReOCl(4)]. A systematic substitution of the alkyl groups in the thiosemicarbazone building blocks of the ligands do not significantly influence the biological activity of the metal complexes, while the replacement of the chloro ligand by a PPh(3) ligand (by the replacement of the oxo unit by a nitrido ligand) completely terminated the cytotoxicity of the metal complexes.

On the cytotoxic activity of Pd(II) complexes of N,N-disubstituted-N′-acyl thioureas

“…The remaining binding sites are occupied by triphenylphosphines (average distance Pd-P1 = 2.2577 Å and Pd-P2 = 2.3455 Å), or by the chloride in the case of complex (1), where the distance Pd-Cl is 2.3269(9) Ả, which is close to those reported in the literature [36]. The distances for the C\S, C\N and C\O bonds in the chelate rings, listed in Table 2, are the characteristic of single and double bond lengths, respectively [44]. The C\O bond distances are slightly sensitive to the coordination of the ligand to the metal.…”

“…The thione C_S bond in the coordinated anionic ligands becomes formally a single bond making it longer (average = 1.7418 Å) than the C_S bond of the neutral moieties [24,25], and the N(2)\C bond (average 1.3252 Å) (Fig. 2, Table 2), which becomes a double bond in the anionic moieties, is typical for C_N distances [44]. The N(1)\C distance, 1.341 Ả (average), is anionic and in the amine form.…”

Syntheses, Structures, and Biological Activity of NiII, PdII, and PtII Complexes with New Tetradentate Benzamidine Ligands

“…[5][6][7][8] Hitherto, only a few tridentate benzamidines, [5][6][7][8] and two tetradentate benzamidines with an S,N,N,S donor set have been reported. [9,10] The coordination chemistry of these ligands is mainly restricted to their rhenium and technetium complexes.…”

Structure/Activity of PtII/N,N-Disubstituted-N’-acylthiourea Complexes: Anti-Tumor and Anti-Mycobacterium tuberculosis Activities

“…For the complexes synthesized in this work, the C-S bond distance is 1.734 Å (average), longer than the C-S bond distance of neutral species (1.661-1.676 Å). 16,21,44,45 For free N,N-disubstituted-N'-acylthioureas, the C-O bonds lengths of 1.214-1.215 Å indicate double-bond character, whereas the C-N bonds, as single one, are at about 1.373-1.412 Å. 44,45 As a result of acylthiourea coordination to the metal, the bond lengths present significant C-S and C-O lengthening and C-N shortening (see Figure 5, Table 2), which is an evidence of resonance effect, as above mentioned in the 13 C{ 1 H} NMR experiment discussion, as a consequence of the deprotonation of the nitrogen atom N-H, which is between the carbonyl and thiocarbonyl groups.…”