CYCLOADDITION REACTION OF THE AZIDO-BRIDGED CYCLOMETALLATED COMPLEX [Pd(dmba)N3]2 WITH CS2. CRYSTAL AND MOLECULAR STRUCTURE OF DI(μ, N,S-l,2,3,4-THIATRIAZOLE-5-THIOLATE)BIS[(N,N-DIMETHYLBENZYL-AMINE-C2,N)PALLADIUM(II)]

Formation and structure of two luminescent salts of [Au(SCSN3)2]- obtained through the [2 + 3] cyclization of carbon disulfide and azide ion

The colorless, two-coordinate gold(i) complex, [(H2O)3Na][Au(SCSN3)2], has been synthesized through the [2 + 3] cyclic reaction of carbon disulfide and sodium azide in the presence of the labile complex (tht)AuCl. Metathesis of [(H2O)3Na][Au(SCSN3)2], with tetra(phenyl)arsonium chloride produced colorless needles of (Ph4As)[Au(SCSN3)2]. The structure of [(H2O)3Na][Au(SCSN3)2] involves linear gold coordination by two exocyclic sulfur atoms of the 1,2,3,4-thiatriazole-5-thiolate anions. These two-coordinate anions self-associate to form extended, zig-zag chains that are connected by aurophilic bonding with Au∙∙∙Au distances of 3.2653(3) Å and 3.3090(3) Å. Remarkably, the individual S-Au-S units that are connected though aurophilic interactions are eclipsed. The structure of (Ph4As)[Au(SCSN3)2] also contains linear, two-coordinate gold ions with bonding to the 1,2,3,4-thiatriazole-5-thiolate anionic ligands through the exocyclic sulfur atoms. However, in this salt, the anions self-associate through AuAu bonds (Au∙∙∙Au distance of 3.2007(3) Å) to form simple dimers, which also have an eclipsed arrangement of the ligands. Electronic structure calculations strongly suggest that the staggered geometry for the [(Au(SCSN3))2](+) dimer is energetically favored relative to the eclipsed geometry. However, attractive π-stacking interactions appear to promote the observed eclipsed arrangement of the ligands.

Antimycobacterial and antitumor activities of palladium(II) complexes containing isonicotinamide (isn): X-ray structure of trans-[Pd(N3)2(isn)(2)]

Complexes of the type trans-[PdX(2)(isn)(2)] {X = Cl (1), N(3) (2), SCN (3), NCO (4); isn = isonicotinamide} were synthesized and evaluated for in vitro antimycobacterial and antitumor activities. The coordination mode of the isonicotinamide and the pseudohalide ligands was inferred by IR spectroscopy. Single crystal X-ray diffraction determination on 2 showed that coordination geometry around Pd(II) is nearly square planar, with the ligands in a trans configuration. All the compounds demonstrated better in vitro activity against Mycobacterium tuberculosis than isonicotinamide and pyrazinamide. Among the complexes, compound 2 was found to be the most active with MIC of 35.89 μM. Complexes 1-4 were also screened for their in vitro antitumor activity towards LM3 and LP07 murine cancer cell lines.

Antitumor and antimycobacterial activities of cyclopalladated complexes: X-ray structure of [Pd(C2,N-dmba)(Br)(tu)] (dmba=N,N-dimethylbenzylamine, tu=thiourea)

The reactions between [Pd(C(2),N-dmba)(micro-X)](2) (dmba=N,N-dimethylbenzylamine; X=Cl, Br) and thiourea (tu) in the 1:2 molar ratio at room temperature resulted in the mononuclear compounds [Pd(C(2),N-dmba)(Cl)(tu)] (1) and [Pd(C(2),N-dmba)(Br)(tu)] (2), which were characterized by elemental analyses and infrared (IR), (1)H- and (13)C{(1)H} NMR spectroscopies. The crystal and molecular structures of 2 were determined by single-crystal X-ray diffraction. In vitro cytotoxicity assays of the compounds 1, 2, tu, dmba and cisplatin were carried out using two murine tumor cell lines, namely mammary adenocarcinoma (LM3) and lung adenocarcinoma (LP07). The compounds 1, 2, tu and dmba were also tested against Mycobacterium tuberculosis and their MIC values were determined.

Investigação eletroquímica de alguns compostos organopaládio (ll): Determinação dos processos de redução do centro metálico em ciclopaladados

Investigou-se o comportamento eletroquímico dos dímeros ciclopaladados [Pd(dmba)(mi-X)]2 [X = Cl (1), NCO (2), NCS (3), CN (4)] (dmba = N,N-dimetilbenzilamina) e do monômero [Pd(dmba)(MeCN)2][NO3] (MeCN = acetonitrila). Os resultados experimentais mostraram redução de Pd(II) para Pd(I) para os compostos 1-3, enquanto que somente para 1 observou-se a redução de Pd(I) para Pd(0) em uma única etapa. O complexo 5 mostrou redução de Pd(II) para Pd(0). Observou-se que a estabilidade eletroquímica destes compostos diminuem na seguinte ordem: [Pd(dmba)(mi-CN)]2 (4) > [Pd(dmba)(mi-NCO)]2 (2) > [Pd(dmba)(mi-SCN)]2 (3) > [Pd(dmba)(MeCN)2][NO3] (5) > [Pd(dmba)(mi-Cl)]2 (1).