1:1 Complexes of palladium(II) and platinum(II) with caffeine and their interaction with nucleosides

The reaction of palladium(II) and platinum(II) with caffeine was studied in dmf and acid aqueous solutions. From dmf solution the 1:1 complexes K[McfCl3] have been isolated and characterized by various physicochemical methods. The complexes are unstable in water, where they decompose to metallic palladium or platinum. The complexes are stabilized in the presence of nucleosides, with which they react, and the following mixed ligand complexes were isolated: [McfNuclCl2] (Nucl = Ado, Guo, or Ino) and [Mcf(NuclH+)Cl] (Nucl = Guo or Ino). These mixed ligand complexes were characterized using various physicochemical methods. Potassium tetrachloroplatinate(II) in acid aqueous solution reacts with caffeine to give the complex [Pt(cfH+)Cl]2, in which caffeine is bound to platinum through its C(8) atom, forming a PtC(8) bond after the removal of the proton bound to that carbon. © 1984

Some reactions of cis-dichlorodiammine palladium(II) with nucleosides

The reactions of cis-Pd(NH3)2Cl2 with nucleosides have been studied in aqueous and dmso solutions. From aqueous solutions, with the nucleosides Ino, Guo and Cyd (= nucl) the complexes [Pd(NH3)2(nucl)2] Cl2 have been isolated, while adenosine gave the dimeric complex {[Pd(NH3)2Cl] 2Ado}Cl2. From dmso solutions the mononucleoside complexes [Pd(NH3)2(nucl)(dmso)] Cl2 have been isolated. These complexes were stable in neutral aqueous solutions, but in alkaline solutions (pH 9-10) those with ionizable N(1)H imino proton, were deprotonated and complexes of the general formula Pd(NH3)2(nucl-H+)Cl precipitated. These complexes were further transformed to the mononucleoside complexes [Pd(NH3)2(nucl)Cl] Cl in acid solution (pH ≅ 1), which in aqueous solution (pH > 5) deprotonated to the parent compound. The isolated complexes were characterized by elemental analyses, conductivity measurements, IR, 1H NMR and 13C NMR spectra. © 1982

Interactions of cysteinato-O-methylesterpalladium(II)-μ-dichloro-cysteinato-O-methylesterpalladium(II) with nucleosides and AMP

The reactions of the binuclear complex Cysteinato-O-methylesterpalladium(II)-μ-dichlorocysteinato-O-methylesterpalladium(II), {Pd(O-MeCys)Cl}2, with nucleosides, Nucl, and adenosine-5′-monophosphate disodium, AMP-Na2, have been studied in aqueous and dmso solutions. From dmso solutions, the monomeric complexes, {Pd(O-MeCys)(NuCl)Cl} were isolated and characterized by elemental analysis, IR, 1H and 13C NMR spectra. In the case of NuCl = inosine (Ino) or guanosine (Guo) the complexes are transformed to {Pd(O-MeCys)(Nucl-H+)}, when dissolved in water. The same complexes were formed by direct mixing of the reactants in water. In these latter complexes the exocyclic oxygen of the 6th position participates in the bonding with the metal, besides the N7 of the purine ring, either in a chelate or a dimeric or polymeric O6N7 manner. The reaction with AMP-Na2 in aqueous solution gave the product: {Pd(O-MeCys)(AMP)}Na. The results indicate that in this complex the nucleotide AMP coordinates to palladium through the N7 atom of the purine ring and the phosphate group, most probably in a chelate form. © 1983

Complexes of palladium (II) with L-proline. Mixed L-prolinato nucleoside complexes of Palladium (II)

The reaction of Palladium (II) chloride and L-proline (ProH) in aqueous solution gave the dimeric complex, Pd(Pro)Cl2, which was characterized by elemental analysis, molecular weight, conductivity measurements and IR and NMR spectra. The complex, reacted further with the purine nucleosides inosine or guanosine (Nucl) and the complexes Pd(Pro)(Nucl-H+) were isolated from aqueous solution. The insolubility of these complexes suggested a rather polymeric structure in which the nucleoside bridges two adjacent palladium atoms through its N(7) and the exocyclic O(6) atoms. Reaction in dmso gave the complex Pd(Pro)(Nucl)Cl in which the nucleoside act as monodentate ligands with their N(7) atom as ligation site. In aqueous solutions these complexes are quantitatively transformed to the polymeric analogues with the liberation of HCl. The nucleoside adenosine (Ado) reacted in a different way giving only the dimeric complex [Cl(Pro)PdAdoPd(Pro)Cl] in which adenosine bridges two palladium atoms through its N(1) and N(7) atoms. Finally with the pyrimidine nucleoside cytidine (Cyd) the monomer Pd(Pro)(Cyd)Cl was isolated. © 1984

1:1 Complexes of palladium(II) and platinum(II) with caffeine and their interaction with nucleosides

The reaction of palladium(II) and platinum(II) with caffeine was studied in dmf and acid aqueous solutions. From dmf solution the 1:1 complexes K[McfCl3] have been isolated and characterized by various physicochemical methods. The complexes are unstable in water, where they decompose to metallic palladium or platinum. The complexes are stabilized in the presence of nucleosides, with which they react, and the following mixed ligand complexes were isolated: [McfNuclCl2] (Nucl = Ado, Guo, or Ino) and [Mcf(NuclH+)Cl] (Nucl = Guo or Ino). These mixed ligand complexes were characterized using various physicochemical methods. Potassium tetrachloroplatinate(II) in acid aqueous solution reacts with caffeine to give the complex [Pt(cfH+)Cl]2, in which caffeine is bound to platinum through its C(8) atom, forming a PtC(8) bond after the removal of the proton bound to that carbon. © 1984

Complexes of palladium (II) with L-proline. Mixed L-prolinato nucleoside complexes of Palladium (II)

The reaction of Palladium (II) chloride and L-proline (ProH) in aqueous solution gave the dimeric complex, Pd(Pro)Cl2, which was characterized by elemental analysis, molecular weight, conductivity measurements and IR and NMR spectra. The complex, reacted further with the purine nucleosides inosine or guanosine (Nucl) and the complexes Pd(Pro)(Nucl-H+) were isolated from aqueous solution. The insolubility of these complexes suggested a rather polymeric structure in which the nucleoside bridges two adjacent palladium atoms through its N(7) and the exocyclic O(6) atoms. Reaction in dmso gave the complex Pd(Pro)(Nucl)Cl in which the nucleoside act as monodentate ligands with their N(7) atom as ligation site. In aqueous solutions these complexes are quantitatively transformed to the polymeric analogues with the liberation of HCl. The nucleoside adenosine (Ado) reacted in a different way giving only the dimeric complex [Cl(Pro)PdAdoPd(Pro)Cl] in which adenosine bridges two palladium atoms through its N(1) and N(7) atoms. Finally with the pyrimidine nucleoside cytidine (Cyd) the monomer Pd(Pro)(Cyd)Cl was isolated. © 1984

Palladium(II) and platinum(II) complexes with pentamethylenetetrazole and their interaction with nucleosides

The reactions of pentamethylenetetrazole with palladium(II) and platinum(II) in aqueous solutions have been studied and the complexes cisM(PMT)2X2 where M is Pd or Pt and X is Cl, Br, or I, isolated and characterized by elemental analysis, IR spectra, conductivity measurements and molecular weight determinations. The complexes further react with nucleosides to yield the mixed ligand complexes [M(PMT)2(Nucl)2]Cl2, where Nucl is inosine, guanosine, or cytidine. In the case of adenosine the dimeric [M(PMT)2Ado]2Cl4 or polymeric [M(PMT)2Ado]Cl2n complexes have been isolated in which adenosine bridges two metal atoms through its N1 and N7 atoms. These mixed ligand complexes were characterized besides the above techniques and by their 1H NMR spectra. © 1980

1,10-phenanthroline-N-oxide chelates with rare earth nitrates

The interactions of 1,10-phenanthroline-N-oxide with the lanthanide nitrates were studied and complexes of the general formulae Ln(PhenNO)2(NO3)3 were isolated from alcoholic solutions. The complexes were characterized by elemental analysis, conductivity measurements and ir spectra . X-ray powder patterns further indicated that the complexes are isomorphous having the same d-interplanar spacings. © 1982

Complexes of palladium(II) with nucleosides. Preparation and properties of complexes of the type potassium trichloro(nucleoside)palladate(II)

The preparation of the monobase complexes K[PdLCl3] (L = nucleoside or pyridine) is described for the first time, in dimethylformamide solutions. The complexes are characterized by elemental analyses, conductivity measurements, i.r. spectra, and chemical reactions. They are unstable in aqueous or acidic solutions. At pH ca. 9-10 the inosine and guanosine derivatives are transformed into dimeric O(6)N(7) chelates. The reactions of K[PdLCl3] with other nucleosides in water have also been studied and produce 1:4 and 1:2 complexes of the type [PdLL′3]Cl2, cis- or trans-[PdL(L′)]Cl2, and cis- or trans-[Pd(L - H) (L′ - H)], where L′ = the same or a different nucleoside to L. The binding sites of these complexes are N(7) of the purine rings, as is revealed by their 1H n.m.r. spectra