Maria Kubiak

The influence of the intramolecular hydrogen bond on the 1,3-N,S- and 1,5-O,S-coordination of N-phosphoryl-N′-(R)-thioureas with Ni(II) and Pd(II)

Reaction of the potassium salts of N-phosphorylated thioureas of common formula R1–N(H)–C(S)–N(H)–P(O)(OiPr)2 (HA) with NiII and PdII cations leads to [MA2] chelate complexes (M = NiII, R1 = p-MeOC6H4, p-BrC6H4, t-Bu, c-Hex; M = PdII, R = iPr). In both the NiII and PdII complexes, the metal center is found in a square-planar N2S2 environment formed by the CS sulfur atoms and the P–N nitrogen atoms of two deprotonated ligands A−. The PdII atoms in [PdB2] complexes with deprotonated thioureas of common formula R2–C(S)–N(H)–P(O)(OiPr)2 (HB) (R2 = Et2N, morpholine-N-yl) are coordinated in a square-planar fashion by the CS sulfur atoms and the PO oxygen atoms of two anionic ligands. Molecular structures of four complexes [M(A-N,S)2] (M = NiII, R1 = p-MeOC6H4, p-BrC6H4, t-Bu; M = PdII, R1 = iPr) and the palladium(II) 1,5-O,S-chelate of formula [Pd(B-O,S)2] (R2 = morpholine-N-yl) were elucidated by X-ray diffraction.

NMR and x-ray studies of Pd(II) and Pt(II) complexes with S-methyl-L-cysteine sulfoxide

Abstract IR, NMR and X-ray studies have shown that in the Pt(II) or Pd(II)S-methyl-L-cysteine sulfoxide (SOMC) complexes the ligand molecule coordinates to the metal ion via the sulfur and amine donors. Two isomers are found in solution which differ by the ligand conformation on the sulfur center. Crystals of dichloro-[(S-methyl-L-cysteine)sulfoxided]palladium(II) monohydrate are orthorhombic, space group P2 1 2 1 2 1 with a = 17.858(4), b = 8.690(3), c = 7.008 (2) A and Z = 4. The structure was solved by the heavy-atom technique and refined by full-matrix least-squares calculations to a final R = 0.061 for 942 counter reflections. Coordination around palladium is slightly distorted square-planar and involves the sulfur and the nitrogen atoms of the amino acid molecule and two chlorine atoms. The five-membered chelate ring has a λ conformation. The R, S absolute configuration of the ligand is confirmed in this study. Only one of the SOMCPd isomers was found to be present in the studied crystals.

Synthesis and characterization of a novel tetranuclear bimetallic complex containing rhodium(II) and zinc(II) as metal centres

Rh(Hdmg)2(PPh3)Cl (Hdmg=monoanion of dimethylglyoxime) undergoes reduction with zinc amalgam to give the tetranuclear bimetallic compound [Rh(Hdmg)(ClZndmg)(PPh3)]2, characterized by elemental analysis, electronic, IR and NMR spectroscopy and X-ray crystallography. It crystallizes in the triclinic space group P1 with: a=14.262(4), b=14.675(4), c=14.698(4) A, α=82.15(4), β=87.57(4), γ=65.89(3)°, Z=2. The structure was refined up to R=0.13 for 4704 reflections. The molecule consists of two [Rh(dmg)(Hdmg)(PPh3)] subunits linked by an [Rh(II)(II)] bond of length equal to 2.852(3) A and by two Zn ions bridging the oxygens of the equatorial ligands. The binding with zinc relieves the equivalence among the atoms of each subunit.

X-Ray evidence for the lysyl lateral amine group coordination in the (L-lysyl-L-tyrosine)Cu(II)•2H2O complex

Abstract X-ray evidence for the lysyl lateral amine group coordination to cupric ion is presented for the Cu(II) complex with L-lysyl-L-tyrosyl dipeptide. The dipeptide molecule is coordinated to the metal ion via all its functions. The α-amine, N− and COO- donors bind the metal ion forming two small chelate rings while ϵ-NH2 is coordinated to the other copper ion related by the screw axis and the polymeric complex is formed.

Synthesis, crystal and molecular structure of the novel complex [dinitrato{N,N-bis(1–methylbenzimidazol-2–ylmethyl)methylamine}]cobalt(II)

Co(NO3)2·6H2O reacts with N,N-bis(1–methylbenzimidazol-2–ylmethyl)methylamine (Me2L) in MeOH/ Et2O solution at ca. 5°C, yielding a novel, penta-coordinate complex, formulated as [Co(NO3)2(Me2L)], which was characterized by means of structural, spectroscopic and magnetic measurements. The Co atom is coordinated in distorted trigonal bipyramidal geometry by three N and two O atoms. The ligand Me2L is coordinated in a facial mode and two coordinated O atoms from the nitrato ligands are in cis-positions.

Crystal structure of a copper(II)–famotidine complex and solution studies of the Cu2+–famotidine–histidine ternary system

The crystal structure of the complex [CuL][ClO4]2(L = 3-{[2-diaminomethyleneamino)thiazol-4-yl]methylsulfanyl}-N2-sulfamoylpropionamidine, famotidine) has been determined. It provides a full description of the metal binding sites and reveals the impact of metal co-ordination on the conformation of the drug molecule. Even metal ion binding is not able to change some conformational features of famotidine, which could be an important factor biologically. Potentiometric and spectroscopic data were obtained for the ternary species in the Cu2+–famotidine–histidine system and show that famotidine is a very competitive chelating agent even in the presence of the strongly co-ordinating amino acid.

Rhodium complexes with diacetyl monoxime ligands; crystal structure of [Rhcis- (C4H6NO)2cis-(PPh3)2]ClO4·CHCl3

Abstract The reaction of RhCl 3 ·3H 2 O with Hdamo and PPh 3 (Hdamo = diacetyl monoxime = C 4 H 7 NO), both in the absence ( 1 ) and in the presence of HClO 4 ( 2 ) afforded the complex Rh(damo)(PPh 3 ) 2 Cl 2 . The reaction of the acidic water/ethanolic solution of [Rh(H 2 O) 6 ] 3+ with Hdamo and PPh 3 ( 3 ) gave the mixture of the isomers of the compound [Rh(damo) 2 (PPh 3 ) 2 ]ClO 4 ( 3A and 3B ). A similar mixture of isomers was formed when [Rh(H 2 O) 6 ] 3+ reacted with H 2 dopn (H 2 dopn = 3,9-dimethyl-4,8-diazaundeca-3,8-diene-2,10-dione dioxime) and PPh 3 ( 4 ). Two isomers ( 4A = 3B ) and [Rh cis -(damo) 2 cis -(PPh 3 ) 2 ]ClO 4 ·CHCl 3 ( 4B ) have been isolated. All the compounds were characterized by elemental analysis NMR and IR spectroscopy. Single-crystal X-ray diffraction studies were carried out on the complex 4B . In this compound the coordination environment around rhodium(III) is pseudooctahedral composed of two cis -oxime nitrogen atoms [av. RhN = 2.031(3) A], two trans -oxime oxygen atoms [av. RhO = 2.026(2) A] and two cis -phosphine phosphorus atoms [av. RhP = 2.403(1) A].

Dimethyl Sulfoxide Containing Platinum(II) and Palladium(II) Chelate Complexes of Glyoxylic and Pyruvic Acid Thiosemicarbazones. A New Class of Cytotoxic Metal Complexes

Abstract The complexes [Pt(DMSO)(GT)]·DMSO (1), [Pt(DMSO)(PT)]· 1/2 DMSO (2) and [Pd(DMSO)- (PT)] (3), where DMSO = dimethyl sulfoxide, H2GT = glyoxylic acid thiosemicarbazone and H2PT = pyruvic acid thiosemicarbazone, have been synthesized and characterized by elemental analysis, molar electric conductivity, IR, electronic and NMR (1H and 13C) spectra. The single crystal X-ray diffraction analysis has revealed for 1 (orthorhombic, Pnma, a = 12.941(3), b = 7.108(2), c = 15.148(3) Å , Z = 4) that the doubly deprotonated thiosemicarbazone molecule is coordinated to Pt(II) via the carboxylato O, azomethine N and thiolato S atoms forming two condensed fivemembered chelate rings. The fourth coordination site of Pt(II) is occupied by the S atom of DMSO. All the atoms of the complex molecule are coplanar except the methyl groups. The O atom of DMSO is in cis-position towards the thiolato-S atom (point group Cs). A system of hydrogen bonds of the type N-H· · ·O links the complex molecules between them and with the lattice DMSO molecules. Similar structures have been deduced for the remaining two complexes on the basis of spectroscopic data. The three complexes and the ligand H2GT exhibit cytotoxic activity against F4N leukemia cells, whereas the ligand H2PT is inactive.

Products of the oxidation of 1-(diaminomethylene)thiourea with hydrogen peroxide.

Two oxidation products of 1-(diaminomethylene)thiourea (HATU) are reported, obtained from reactions with hydrogen peroxide at two different concentrations; these are 3,5-diamino-1,2,4-thiadiazole, C(2)H(4)N(4)S, (I), related to HATU by intramolecular N-S bond formation, and 1-(diaminomethylene)uronium hydrogen sulfate, C(2)H(7)N(4)O(+).HSO(4)(-), (II). In (I), molecular hydrogen-bonded chains could be distinguished, further organized in a herring-bone-like pattern. The structure of (II) is stabilized by an extensive network of N-H...O and O-H...O hydrogen bonds, where hydrogen-bonded anion chains and characteristic cation-anion motifs are present. The compounds are of importance not only with respect to crystal engineering, but also in the design of new synthetic routes to HATU transition metal complexes.

Crystal and molecular structure of a cobalt(II) complex with bis(benzimidazol-2-ylmethyl)-methylamine (L)

The reaction product of Co(II) chloride and the title ligand L, formulated as CoLCl2·CH3OH, was prepared and characterized by means of structural and spectroscopic measurements. The violet crystals are orthorhombic, (space groupP212121) witha=8.093(2),b=14.883(3),c=16.831(3) Å, andZ=4. The structure consists of discrete molecules with pseudo-, noncrystallographic twofold symmetry in which the Co atom is coordinated in trigonal bipyramidal geometry by three nitrogen and two chlorine atoms. The ligand L is coordinated to the Co atom in afac mode and two chlorine atoms are incis-positions. The structure was confirmed by IR-spectra.