Amparo Sancho

Crystal structure, spectroscopic characterisation and magnetic properties of [Cu(BIP)(N3)]·H2O (BIP=3,3-bis(2-imidazolyl)propionate), a copper(II) polymeric compound with asymmetrical μ-1,3-azido bridges

Abstract The structure and the spectroscopic and magnetic properties of [3,3-bis(2-imidazolyl)propionato]azidocopper(II) monohydrate are described. The compound is built of [Cu(BIP)N3] entities which are connected through carboxylate groups from the BIP molecules —which act as a tridentate ligand—and asymmetrical μ-1,3-azido bridges, leading to a polymeric sheet-like structure. The copper atom is involved in a CuN3ON′ chromophore and lies in a distorted square-pyramidal environment. Both electronic and EPR spectra are indicative of an essentially dx2−y2 ground state for the copper(II) ions. Magnetic susceptibility measurements in the range 1.8–200 K show very weak antiferromagnetic exchange between the copper(II) ions (2J=−0.48 cm−1). This feature is discussed on the basis of the relative orientation of the coordination polyhedron around the metal atom and the bridging network.

Crystal structure of copper(II) cimetidine sulphate nonahydrate. Cation distortion and structure isomerism in three copper(II) cimetidine complexes

Abstract In the crystalline state, the complex [Cu(CM) 2 ]SO 4 ·9H 2 O (CM = cimetidine) is constituted of two-dimensional cations[Cu(CM) 2 2+ ] n separated by SO 4 2− anions and water molecules. As in the related complexes [Cu(CM) 2 ](ClO 4 ) 2 and [Cu(CM) 2 ](NO 3 ) 2 , the copper atom lies in a strongly distorted octahedral CuN 4 S 2 environment. The distortion is quite different from one complex to another (cation distortion isomerism). In the title compound the CuS bond is unusually long (2.91 A). Unlike the title compound, the [Cu(CM) 2 2+ ] n cations in the perchlorate and nitrate salts are one-dimensional infinite chains characterized by different conformations of the cimetidine molecules (cation structure isomerism).

Crystal and molecular structure and electronic properties of [Cu(HBIP) (BIP) (ONO2)] (HBIP = 3,3-bis(2-imidazolyl)propionic acid)

Abstract The crystal and molecular structure of the complex [Cu(HBIP) (BIP)ONO2] (HBIP = 3,3-bis(2-imidazolyl)propionic acid) has been determined by X-ray methods. It crystallises in the monoclinic space group C2/c, Z=4, a=11.350(2), b=13.156(2), c=14.225(2) A , s=95.36(2)°, V=2114.8(6) A 3 . The CuN4O chromophore could be considered as an intermediate between the trigonal bipyramid (TBP) and square pyramid (SP). Neighbouring molecules of the complex are bound by very strong hydrogen bonds, as short as 2.478 A, between COO− and COOH groups. Electronic and EPR spectra are consistent with the crystallographic data.

Cobalt(II), nickel(II) and copper(II) complexes withN-cyano-N′-methyl-N″(2-[(5-methyl-1H-imidazol-4-yl)methylthio]ethyl)guanidine

SummaryN-Cyano-N′-methyl-N″(2-[(5-methyl-1H-imidazol-4-yl)-methylthio] ethyl) guanidine cimetidine (CM), complexes with CoII, NiII and CuII are described. The compounds are of stoichiometry [M(CM)2]SO4 · nH2O [M = CoII, NiII or CuII; n = 3,3 or 4, respectively], [M(CM)2](ClO4)2 [M = CoII or NiII], [M(CM)2]Cl2 · nH2O [M=CoII, NiII or CuII; n = 1, 2, or 2, respectively] and [Cu(CM)SO4] · 2H2O. The electronic spectra of the compounds in solid state, magnetic susceptibilities and i.r. and e.p.r. spectra were studied. Octahedral environments are proposed for the complexes: [M(CM)2]SO4·nH2O, [M(CM)2](ClO4)2, [Ni(CM)2]Cl2 · 2H2O, [Cu(CM)2]Cl2 · 2H2O and [Cu(CM)SO4] · 2H2O and a tetrahedral structure for [Co(CM)2]Cl2 · H2O.

Cimetidine complexes derived from cobalt(II), nickel(II) and copper(II) salts of polyatomic anions

SummaryCobalt(II), nickel(II) and copper(II) complexes [M(CM)2]X2 (X = BF4 or NO3) have been prepared with cimetidine (CM). Powder data, molar conductivities, magnetic moments, i.r. and electronic spectra support apseudo-octahedral stereochemistry with MN2N2⋆S2 chromophore and tentative structures are proposed for the complexes. Their properties are compared with these of previously prepared complexes.

Synthesis, properties and crystal structure of bis(metiamide)bis(isothiocyanato)nickel(II)

Abstract The crystal structure of Ni(metiamide)2(NCS)2 was determined by X-ray diffraction methods. Unlike cimetidine, which is a tridentate ligand, metiamide (C9H16N4S2): N-Methyl-N-[2-{(5-methylimidazol-4-yl)methylthio}ethyl]thiourea (which also possesses three potential donor sites) is bidentate, coordinated to the nickel atom through N(imidazole) and S(thioether) atoms. The S(thiourea) atom does not take part in the coordination; instead, the isothiocyanate ion is coordinated through nitrogen to the metal atom. The nickel atom lies on a centre of symmetry in an elongated octahedral environment: the nitrogen atoms occupy equatorial positions (NiN = 2.04 and 2.06 A) and S(thioether) atoms occupy apical positions (NiS = 2.58 A). Individual molecules are linked together by a unique S ⋯ HN hydrogen bond involving the uncoordinated S(thiourea) atom. IR, electronic reflectance and magnetic data are consistent with the structural results.

Thermal study of cobalt(II), copper(II) and nickel(II) complexes of cimetidine

Abstract The thermal behaviour of cobalt(II), nickel(II) and copper(II) complexes of cimetidine has been studied using thermogravimetry (TG) and differential scanning calorimetry (DSC). The complexes decompose in two steps: dehydration and decomposition. The decomposition products have been characterised by X-ray powder diffraction patterns.

Thermal decomposition of metal complexes of cimetidine

Abstract A study of the thermal decomposition of [M(cimetidine)2]X2 · nH2O complexes 1 where M = Co(II), Ni(II) and Cu(II), X = 1 2SO 4 , NO3 and BF4 is reported. The sulphate complexes decompose by two processes: dehydration and pyrolytic decomposition. The nitrate and tetrafluoroborate cimetidine complexes undergo only the pyrolytic decomposition process.