Inessa A. Efimenko

Binary palladium carboxylates with electron-donating and electron-withdrawing substituents in the carboxylate ligand: Synthesis and structural studies. The crystal structures of Pd3(μ-CH2ClCO2)6 · CH2Cl2, Pd3(μ-C6H11CO2)6, and Pd3(μ-CMe3CO2)6

Replacement of the acetate ligands in Pd3(μ-MeCO2)6 in benzene gave complexes of the general formula Pd3(μ-RCO2)6 (R = CF3, CCl3, CH2Cl, Me, cyclo-C6H11, and CMe3). The structures of the complexes were determined using IR spectroscopy, ESI mass spectrometry, and X-ray diffraction. It was found that the complexes contain a trinuclear Pd framework and that their spectroscopic and structural parameters depend on the donor-acceptor properties of the substituent in the carboxylate ligand.

Synthesis and structure of palladium(II) mixed complexes with DNA purine or pyrimidine bases and imidazole derivatives. Part I

SummaryPalladium(II) mixed ligand complexes with purine or pyrimidine and imidazole derivatives were prepared and characterized by i.r., Raman and electronic spectroscopy. The compounds have the general formula [Pd(L1)(L2)(X2)]; where L1 = adenine, guanine, hypoxanthine, cytosine, 2-aminopyrimidine, 4(6)-hydroxypyrimidine; L2 = N-methylimidazole, N-ethylimidazole or N-propylimidazole; X = Cl or Br. The complexes are square planar with cis-halogens. The purine, pyrimidine and imidazole bases act as monodentate ligands coordinated via the N(7) of purine and N(3) of pyrimidine and imidazole.

Reaction products distribution between square-planar gold(III) complexes and N,N,N′,N′-tetramethylthiuram disulfide. Crystal structure of bis(N,N-dimethyldithiocarbamato)gold(III) bromide dihydrate, [Au(Me2NCS2)2]Br·2H2O

SummaryThe reactions of N,N,N′,N′-tetramethylthiuram disulfide (tmtds) with gold(III) complexes of the [Au(L)X3] type [L = N-methylimidazole (N-Melm), 2-methylbenzoxazole (2-MeBO) and 2,5-dimethylbenzoxazole (2,5-diMeBO), X = Cl, Br or I] are reported, and yielded two main types of product - [Au(Me2dtc)X2] (A) and [Au(Me2dtc)2]X (B) (Me2dtc = N,N-dimethyldithiocarbamato anion). The ratio of the product yields (B/A) depends upon the nature of the ligand (L) and halogen (X). The ratio B/A for the reaction: [Au(L)Cl3] + tmtds = A + B, increases in the sequence N-MeIm < 2- MeBO < 2,5-diMeBO, which correlates well with the level of cytotoxic activity exhibited by the [Au(L)Cl3] complexes. A and B were characterized by their i.r., u.v-vis. and 1-n.m.r. spectra. The magnetic measurements were also recorded. The data support a squareplanar geometry for gold(III) complexes with the Me2dtc ligand bonded in a bidentate fashion; a conjecture has been verified crystallographically for [Au(Me2NCS2)2]-Br·2H2O. The X-ray analysis confirmed that the complex is composed of ionic units: [Au(Me2dtc)2] + and Br− and H2O molecules. The Au—S distances are markedly similar, falling in the 2.343(4)–2.350(3) ∘A range.

Gold(III) complexes with imidazole, benzoxazole, purine and pyrimidine derivatives

SummaryThe synthesis and characterization of AuIII complexes with several heterocyclic ligands are reported. The compounds have general formula [AuX3(L)], where L =N-methylimidazole (N-MeIz),N-ethylimidazole (N-EtIz),N-propylimidazole (N-PrIz), benzoxazole (BO), 2-methylbenzoxazole (2-MeBO), 2,5-dimethylbenzoxazole (2,5-diMeBO), 2-amino-pyrimidine (2-APm), 4(6) -hydroxy-pyrimidine [4(6)-hydrPm] or hypoxanthine (Hypox) and X = Cl or Br. Elemental analysis, conductivity measurements and spectral studies were used for the characterization of the complexes. A square-planar geometry withN-bonded heterocyclic ligands is suggested.

Gold(I) complexes of azoles

Summary(Dimethyl sulphide)AuCl reacts with azoles to give adducts [LAuX]2 [L = N-methylimidazole (N-MeIm), N-ethylimidazole (N-EtIm), N-propylimidazole (N-PrIm), 2-methylbenzoxazole (2-MeBO) and 2,5-dimethylbenzoxazole (2,5-diMeBO); X = Cl or Br] which were characterized analytically and spectroscopically, including 1H-n.m.r. I.r. and Raman studies showed that the compounds were binuclear with bridging halogen atoms. A nitrogen-containing ligand was coordinated to nitrogen N(3) atom of the azole ring in monodentate fashion.

Interaction of cystamine with palladium(II) monoethanolaminate complex: Crystal structure of [Pd(NH2CH2CH2OH)4][Pd6(NH2CH2CH2S)8]Cl6 · 5H2O

The new compound [Pd(NH2CH2CH2OH)4][Pd6(NH2CH2CH2S)8]Cl6 · 5H2O (I) is synthesized and its crystal structure is determined. The crystals are monoclinic, a = 25.625(6) Å, b = 9.633(5) Å, c = 24.847(7) Å, β = 91.47(2)°, Z = 4, and space group C2/c. The structural units of crystals I are the centrosymmetric hexanuclear [Pd6(NH2CH2CH2S)8]4+ cations, the mononuclear [Pd(NH2CH2CH2OH)4]2+ cations with C2 symmetry, the Cl− anions, and crystallization water molecules. In the hexanuclear cation, the interaction between the Pd atoms occurs through the S atoms of the mercaptoethylaminate ligands. The Pd(2) and Pd(3) atoms and the ligands form two metallochelate fragments in which the N and S atoms are located in cis positions. The average lengths of the Pd-S and Pd-N bonds are equal to 2.274(1) and 2.074(6) Å, respectively. The metallochelate fragments are joined to each other and to their centrosymmetric analogues through the Pd(1) atom, which coordinates four S atoms [the average Pd-Sav bond length is 2.332(1) Å]. In the mononuclear cation, the Pd(4) atom coordinates four N atoms of the monoethylaminate ligands [the Pd-N bond lengths are 2.045(6) and 2.056(6) Å]. The shortest Pd⋯Pd distance is equal to 3.207(1) Å. The bonding in the structure is provided by numerous hydrogen bonds with the participation of all the H2O molecules, NH2 groups, and Cl− anions.

Interaction of Palladium(II) Acido Complexes with DNA

Interaction of K2[PdCl4] (I) and (C5H12NO)2[PdCl4] (II) with DNA in vitro is studied. No fragmentation of DNA occurs under the action of II. The interstrand cross-links are formed due to the formation of complexes with purine and pyrimidine bases; no interaction with DNA phosphates is observed. The cation does not play an essential role in the formation of cross-links.

Synthesis and structures of platinum(II) mixed ligand complexes with purine or piyrimidine bases of DNA and imidazole derivatives. Part 2

SummaryPlatinum(II) mixed ligand complexes with either purine or pyrimidine and imidazole derivatives were prepared and characterized by i.r., Raman and electronic spectroscopy. The compounds had the general formula [PtL1L2Cl2], where L1 = adenine, guanine, hypoxanthine, cytosine, 2-aminopyrimidine; L2 =N-methylimidazole,N-ethyl-imidazole orN-propylimidazole. The platinum(II) complexes had a square planar structure withcis-halogens. Purine or pyrimidine and imidazole derivatived bases acted as monodentate ligands coordinated via the N(7) of purine and N(3) of pyrimidine and imidazole derivatives.

Polymeric palladium(II) dicarboxylate complexes with НOOC–R–COOH, where R is CH=C(CH3), CH2–C(=CH2), or CH=CH: Unconventional transformation of palladium citraconate with the formation of a metal chelate with the Pd–C bond in the tetranuclear complex [Pd(μ-OОC)С(СН3)(OH)СН(COOH)(CH3CN)]4 ∙ 2H2O

Polymeric palladium complexes with citraconic, itaconic, and maleic acids [Pd(μ-OOC–R–COO)(H2O)]n · (0.1 НOOC–R–COOH)n, where R is CH=C(CH3) (1), CH2–C(=CH2) (2), or CH=CH (3), in which the coordination surrounding of palladium consists of bridging acid carboxylate groups and complemented with water molecules linked by hydrogen bonds to the oxygen atoms of the non-coordinated carboxylate groups of citraconic, itaconic, and maleic ions, have been synthesized for the first time. The reaction between palladium citraconate 1 and CH3CN in acetone results in the tetranuclear complex [Pd(μ- OОC)С(СН3)(OH)СН(COOH)(CH3CN)]4 · 2H2O (4), whose structure has been characterized by X-ray diffraction. The reduction of the double bond in the citraconate ion and, as a consequence, the formation of the Pd–C bond result in that each of the four palladium atoms forms a five-membered chelate ring linked to the second non-coordinated carboxylate branch of citraconic acid.

Binary α-unsaturated palladium carboxylates and their complexes with morpholine derivatives: the Crystal structure of palladium carbamoyl crotonate (OC4H8NH)2Pd[OC4H8N(C=O)](MeCH=CHCO2) · H2O, a product of the first inner-sphere amination reaction of α-unsaturated palladium carbonyl carboxylates with morpholine

Binary α-unsaturated palladium carboxylates have been synthesized by substitution of α-unsaturated acids RCOOH (R is CH2=C(Me), MeCH=CH, PhCH=CH) for the acetate ion in Pd3(μ-MeCOO)6. These carboxylates react with amines A (A is morpholine (M), methylmorpholine (MM), or thiomorpholine (MS)) to give trans-Pd(A)2(RCOO)2 similar to trans-A2(MeCO2)2. The structures of the trans-Pd(A)2(RCOO)2 complexes (R is MeCH=CH; A is M, MM, MS) have been determined by X-ray crystallography. The effect of solvent on the crystal structure of the complexes has been demonstrated for trans-(MeCH=CHCO2)2Pd(C4H9NO)2 as an example. The amination reaction of palladium carbonyl crotonate with a secondary amine, morpholine, has been studied for the first time. The reaction involves disproportionation of Pd(I) into Pd(0) and Pd(II) and leads to the first unsaturated palladium(II) carbamoyl carboxylate—palladium carbamoyl crotonate trans-(OC4H8NH)2Pd[OC4H8NC(=O)](MeCH=CHCO2) · H2O, as well as to trans-M2Pd(MeCH=CHCO2)2 and (C4H10NO)+(MeCH=CHCO2)−. The structures of these compounds have been proved by X-ray crystallography.