Sonia Mañas

Visible-Light Photoisomerization and Photoaquation of trans-[Ru(1,3,5-triaza-7-phosphaadamantane)4Cl2] in Organic Solvent and Water

The interaction of the PTA (PTA = 1,3,5-triaza-7-phosphaadamantane) ruthenium complex trans-[RuCl(2)(PTA)(4)] (trans-1) with visible light in chloroform and in water has been studied at room temperature. The complex trans-1 isomerizes to the cis isomer in CHCl(3) with radiation of lambda > 416 nm (Phi(434 nm) (CHCl(3)) = 0.13 +/- 0.01). The isomerization reaction is reversible as cis-1 is transformed into trans-1 with lambda = 367 nm (Phi(367 nm) (CHCl(3)) = 0.25 +/- 0.02). Irradiation at lambda > 416 nm of a solution of trans-1 in water leads to the cis-isomer complex and to the aqua complex (OC-6-32)-[RuCl(H(2)O)(PTA)(4)]Cl (2Cl) by a photoisomerization and photoaquation reaction (Phi(434 nm) (D(2)O) = 0.27 +/- 0.02). The mole ratio of cis-1 to 2Cl is not dependent on the pH but on the concentration of the products in solution. Isomerization in water is not reversible even if only cis-1 is present in solution. Synthesis and characterization of (OC-6-32)-[RuCl(H(2)O)(PTA)(4)](CF(3)SO(3)) (2CF(3)SO(3)) are also presented.

Palladium phosphine complexes from 8-(thio)-theophylline, 8-(methylthio)-theophylline and 8-(benzylthio)-theophylline

Abstract A series of palladium(II) complexes have been synthesized and characterized to examine the coordination chemistry of several 8-thio-purine derivatives: 8-(thio)-theophylline (8-TTH2), 8-(benzylthio)-theophylline (8-BzTTH) and 8-(methylthio)-theophylline (8-MTTH). All of the complexes have been studied by IR and multinuclear (1H, 31P, 13C NMR) spectroscopy. A representative example of a Pd complex, [cis-Pd(8-BzTT)2(PPh3)2], has been authenticated by X-ray crystallography. In this complex square-planar coordination about palladium occurs through two deprotonated N7 purine atoms cis to each other, and two triphenylphosphine phosphorus atoms. In this paper, we present and discuss details of the synthesis, characterization and structural properties of the novel complexes. The synthesis and the characterization of 8-(benzylthio)-theophylline (8-BzTTH), a new organic ligands based on the molecular skeleton of 8-thio-purine, and a new procedure to obtain 8-(methylthio)-theophylline (8-MTTH) are also presented.

Substitution process in phosphine thiopurine palladium complexes

Abstract The synthesis and characterization of the new palladium phosphane thiopurine complexes [PdCl(Py)(PPh 3 )(8-MTT)] ( 1 ) (8-MTTH=8-methylthiotheophylline) and [PdBr(Py)(PPh 3 )(8-BzTT)] ( 2 ) (8-BzTTH=8-benzylthiotheophylline) are presented. Both complexes have been studied by IR and multinuclear ( 1 H, 31 P{ 1 H}) NMR spectroscopy. In addition, the solid state structure of 2 has been authenticated by X-ray crystallography. In this complex, a square-planar coordination around palladium occurs through a deprotonated N7 8-BzTT − atom trans to a Br − atom, and cis to a PPh 3 and to a pyridine. The substitution process that exchanges one of the two PPh 3 ligands in trans -[PdCl(PPh 3 ) 2 (8-MTT)] by a pyridine to produce 1 has also been studied by multinuclear NMR and GS–MS.

New palladium complexes with bis(8-thiotheophylline)alkane derivatives

Abstract Aiming at finding new models that allow us to obtain more information about the interaction between metals and purine-biomolecules, the new derivatives bis(S-8-thiotheophylline)methane (MBTTH2) (1), 1,2-bis(S-8-thiotheophylline)ethane (EBTTH2) (2), 1,3-bis(S-8-thiotheophylline)propane (PBTTH2) (3) and, 1,10-bis(S-8-thiotheophylline)decane (DBTTH2) (4) were synthesised. The evaluation of the coordinative properties of these new ligands against cis-[PdCl2(PPh3)2], leaded to the synthesis of the complexes trans-[PdCl(PPh3)2LH] (L=EBTT2− (5), PBTT2− (6)) and trans-[(PdCl(PPh3)2)2L] (L=MBTT2− (7), EBTT2− (8), PBTT2− (9), DBTT2− (10)). All of the ligands and complexes were characterised by elemental analysis, IR and multinuclear (1H, 13C{1H}, 31P{1H} NMR) spectroscopy. The crystal structure of the ligand 1 is also presented, confirming the proposed composition for the new purine derivatives.