ABSTRACT
New neutral Pd(II) and Pt(II) complexes of the type [M(L)(PPh(3))] (M = Pd or Pt) were prepared in crystalline form in high-yield synthesis with the S-benzyldithiocarbazates and S-4-nitrobenzyldithiocarbazates derivatives from 2-hydroxyacetophenone, H(2)L(1a) and H(2)L(1b), and benzoylacetone, H(2)L(2a) and H(2)L(2b). The new complexes [Pt(L(1a))(PPh(3))] (1), [Pd(L(1a))(PPh(3))] (2), [Pt(L(1b))(PPh(3))] (3), [Pd(L(1b))(PPh(3))] (4), [Pt(L(2a))(PPh(3))] (5), [Pd(L(2a))(PPh(3))] (6), [Pt(L(2b))(PPh(3))] (7) and [Pd(L(2b))(PPh(3))] (8) were characterized on the basis of elemental analysis, conductivity measurements, UV-visible, IR, electrospray ionization mass spectrometry (ESI-MS), NMR ((1)H and (31)P) and by X-ray diffraction studies. The studies showed that differently from what was observed for the H(2)L(1a) and H(2)L(1b) ligands, H(2)L(2a) and H(2)L(2b) assume cyclic forms as 5-hydroxypyrazolinic. Upon coordination, H(2)L(2a) and H(2)L(2b) suffer ring-opening reaction, coordinating in the same manner as H(2)L(1a) and H(2)L(1b), deprotonated and in O,N,S-tridentate mode to the (MPPh(3))(2+) moiety. All complexes show a quite similar planar fourfold environment around the M(II) center. Furthermore, these complexes exhibited biological activity on extra and intracellular forms of Trypanosoma cruzi in a time- and concentration-dependent manner with IC(50) values ranging from 7.8 to 18.7 µM, while the ligand H(2)L(2a) presented a trypanocidal activity on trypomastigote form better than the standard drug benznidazole.
Subject(s)
Coordination Complexes/pharmacology , Hydrazines/chemistry , Palladium/chemistry , Platinum/chemistry , Trypanosoma cruzi/drug effects , Animals , Coordination Complexes/chemistry , Magnetic Resonance Spectroscopy , Molecular StructureABSTRACT
The reaction of Hg(TePh)2 with AgX (X = Cl, NO3) in the presence of PPh3 and PMePh2 in dimethylformamide (DMF) affords the cluster [Hg6Ag4(TePh)16] (1) at room temperature or [Hg6Ag4Te(TePh)14]2 (2) with heating. When Hg(TePh)2 is reacted with [Co(PPh3)2Cl2] or [Ni(PPh3)2Cl2], the clusters [Hg8Te(PhTe)12Cl4]Q [3; Q = [Co(DMF)6]2+ (3a), [Ni(DMF)6]2+ (3b)] are formed. The syntheses of 1 and 2 occur with the incorporation of AgI into the cluster, and the single-crystal analyses show that the two ternary clusters consist of Hg, Ag, and Te centers occupying well-defined positions. Compounds 3a and 3b do not show the incorporation of the metal into the cluster, but the CoII and NiII salts provide the Cl atom to generate the anionic cluster 3 stabilized by the [Co(DMF)6]2+ or [Ni(DMF)6]2+ ion.
ABSTRACT
The first structurally characterized alkali metal phosphonate, the title compound, [K2(C6H6O3P)2(C3H7NO)(H2O)]n, has a complex structure, with layers parallel to the crystallographic bc plane consisting of two crystallographically independent K atoms sandwiched between the three types of ligands present in the structure, viz. water molecules, dimethylformamide molecules and two crystallographically independent phenylphosphonate ligands. Six O atoms coordinate to one K atom and seven to the other. The interlayer distance is 15.327 (4) A. The K-O distances are in the range 2.739 (2)-2.932 (2) A for the seven-coordinate K atom and 2.650 (2)-2.821 (2) A for the six-coordinate K atom.
ABSTRACT
The structure of the title compound, [PtCl(2)(C(5)H(5)N)(C(2)H(6)S)], consists of discrete molecules in which the Pt-atom coordination is slightly distorted square planar. The Cl atoms are trans to each other, with a Cl-Pt-Cl angle of 176.60 (7) degrees. The pyridine ligand is rotated 64.5 (2) degrees from the Pt square plane and one of the Pt-Cl bonds essentially bisects the C-S-C angle of the dimethyl sulfide ligand. In the crystal structure, there are extensive weak C-H...Cl interactions, the shortest of which connects molecules into centrosymmetric dimers. A comparison of the structural trans influence on Pt-S and Pt-N distances for PtS(CH(3))(2) and Pt(pyridine) fragments, respectively, in square-planar Pt(II) complexes is presented.
