B. Viossat

Structure du trans-dichlorobis(pyridine)palladium(II)

[PdCl 2 (C 5 H 5 N) 2 ], M r =335.51, monoclinic, C2/c, a=8.774 (1), b=15.474 (2), c=8.635 (1) A, β=90.56 (1) o , V=1172.3 (3) A 3 , Z=4, D m =1.87 (3), D x =1.90 Mg m -3 , λ(Mo Kα)=0.7107 A, μ=1.991 mm -1 , F(000)=656, T=295 (1) K, final R=0.033 for 1086 independent observed reflections. The title compound exhibits twofold internal geometry: the Pd atom, and the N(1), C(3), N(2) and C(6) atoms of two independent pyridine molecules lie on the binary axis. The complex consists of discrete molecules with Pd showing the usual square-planar coordination with two Cl atoms at 2.297A and two N atoms of the pyridine molecules at 2.024A

A mixed-ligand homodinuclear copper(II) complex with weak disulfide-metal interactions: synthesis, properties and molecular and crystal structure of μ-(N,N,N′,N′-Tetrakis(carboxymethyl)cystaminato(4−))-bis(imidazole)diaquodicopper(II) dihydrate, [Cu2(TTC)(ImH)2(H2O)2]·2H2O

Abstract μ-(N,N,N′,N′-Tetrakis(carboxymethyl)cystaminato (4−))-bis(imidazole)diaquodicopper dihydrate, [Cu2- (TCC)(ImH)2(H2O)2]·2H2O (I) (where TCC = (O2- CCH2)2NC2H4SSC2H4N(CH2CO2)24−), has been obtained in good yield by reaction of [Cu2 (TCC)(H2O)2]·4H2O (II) with excess of imidazole (ImH) in water. The new product I has been characterized by chemical analysis, TG-DTA diagram, infrared, reflectance and ESR spectra and the single- crystal X-ray diffraction method. The compound crystallizes in the monoclinic system, space group P21/n (a = 20.800(2), b = 10.191(2), c = 13.419(2) A, β = 92.41(1)°). Final R = 0.036 and Rw, = 0.035 for 2784 independent observed reflections. Instead of the polynuclear layered crystal structure of II, the crystal of I consists of hydrogen bonded water molecules and discrete dinuclear units [Cu2(TCC)- (ImH)2(H2O)2] linked together in a tridimensional hydrogen bonding network. Both crystallographic independent copper atoms of the mixed dinuclear unit show analogous distorted elongated octahedral coordination (of the type 4 + 1 + 1). The two CuN(ImH) bonds are shorter than the homologous bond in a variety of copper(II)imidazole derivatives, lying in the lowest limit of the corresponding bond lengths in Cu(II)(ImH)aminoacidato (or peptide) complexes (1.95–1.98 A). However, the ImH ligands do not play any π acceptor role (the CuN(ImH) bonds are tilted with respect to the ImH planes, which are twisted with respect to the mean equatorial coordination planes of the copper(II) atoms). By reacting ImH with II to give I, the copper coordinated water molecule in the equatorial position in II is replaced by an ImH molecule in I and moves to an apical position; this results in the lengthening of the CuS(disulfide) bonds, from 2.721(3) A in II to 2.959(2) A, average in I.

Les Composés de la Metformine avec les Ions CoII, CuII et NiII

The structures of trichloro(N,N-dimethylbiguanidium)-cobalt(II), [Co(C 4 H 12 N 5 )Cl 3 ], (I), and di-μ-chlorobis-[chloro-(N,N-dimethylbiguanide)copper(II)], [CuCl 2 -(C 4 H 11 N 5 )] 2 , (II), consist of the metal atom bound to three Cl atoms and to one or two N atoms, respectively, belonging to one metformine ligand. The structures of bis(N,N-dimethylbiguanide)copper(II) dichloride dihydrate [Cu(C 4 H 11 N 5 ) 2 ]Cl 2 .2H 2 O, (III), and bis-(N,N-dimethylbiguanide)nickel(II) monohydroxide chloride, [Ni(C 4 H 11 N 5 ) 2 ](Cl)(OH), (IV), are formed of [M(metformine) 2 ] 2+ (M = Cu or Ni) and anions (Cl- or OH - ). In these compounds, the metal is on a centre of symmetry and forms a square-planar structure comprising four N atoms of two N,N-dimethylbiguanidine ligands. The metformine ligand is planar in (II), (III) and (IV), allowing delocalization of the π-electron system in the metal-ligand ring, but not in (I), where the dihedral angle between the two guanidine groups is 68.4(2)°. The four structures are stabilized by hydrogen bonding and van der Waals interactions.

L'hydrogénocarbonate de Bis(N,N-diméthylbiguanide) Cuivre(II), [Cu(C4H11N5)2]2HCO3

The structure of bis(N 1 ,N 1 -dimethylbiguanide- N 2 ,N 4 )copper(II) bis(hydrogencarbonate) consists of a [Cu(C 4 H 11 N 5 ) 2 ] 2+ cation and two HCO 3 + anions. The Cu atom is at a centre of symmetry and forms a square-planar structure with four N atoms belonging to two N,N-dimethylbiguanide (metformin) groups. The metformin ligand is planar, allowing delocalization of the π electrons in the metal-ligand ring. The hydrogencarbonate anions are hydrogen bonded to N(I), N(2) and N(3)

Tétrachlorocuprate(II) de metformine

The structure of metformine tetrachlorocuprate(II), (C 4 H 13 N 5 )[CuCl 4 ], consists of an N,N-dimethylbiguanidium cation and a squashed tetrahedral CuCl 4 2- anion, which has Cl-Cu-Cl bond angles equal to 136 and 96 o . The two guanide groups are not coplanar, the angle between the two guanide planes is 132.7 (5). There are several N-H...Cl hydrogen bonds between the organic cation and the tetrachlorocuprate anion

Chlorure de cis-Chloro(diméthyl sulfoxyde)(metformine)platine(II)

In this cis-chloro (dimethyl sulfoxide)(metformin)platinum (II) chloride complex (metformin is 1,1-dimethyl-biguanide), [PtCl(C 4 H 11 N 5 )(C 2 H 6 OS)]Cl, the coordination about the Pt atom is square planar, involving Cl, S and two N atoms. The N atoms are in cis positions and belong to the metformin ligand. In the complex cation, the metformin-Pt ring is approximately planar. There is a delocalized orbital over the biguadine group. An N-H...O intramolecular hydrogen bond [2.75 (1) A] forms a pseudo five-membered ring. Several N-H...Cl intermolecular hydrogen bonds take part in the cohesion of the structure

Dibromidobis-(4-hydr-oxy-1,5-dimethyl-2-phenyl-3-pyrazolone)zinc(II).

In the title compound, [ZnBr2(C11H12N2O2)2], the Zn(II) ion is coordinated by two Br atoms and two O atoms from two 4-hydroxyantipyrine molecules via the carbonyl O atoms, which act as monodentate ligands, giving rise to a distorted tetrahedral geometry. The values of the bond angles at the Zn atom are in the range 99.4 (1) to 113.2 (1)°. The presence of O—H⋯O and O—H⋯Br intramolecular hydrogen bonds can explain the difference between the two Zn—O [1.961 (3)/2.015 (3) Å] and the two Zn—Br [2.350 (1)/2.378 (1) Å] bond lengths. The crystal structure is governed by C—H⋯O, C—H⋯Br and Zn—Br⋯Cg(π-ring) interactions.

2‐(2‐Aminophénylthio)‐2‐(2‐thiényl)éthyl 2‐Thiényl Cétone

The X-ray structure of the title compound, C17H15NOS3, unambiguously establishes the nature of the unexpected and non-cyclized compound obtained by reacting 2-aminobenzenethiol with 1-(2-thienyl)-3-(2-thienyl)-2-propen-1-one. The molecule as a whole is not planar, the two thienyl rings, P1 and P2, and the phenyl ring, P3, are planar and make (P1, P2), (P1, P3) and (P2, P3) dihedral angles of 75.9 (2), 31.9 (2) and 70.7 (1)°, respectively. Atoms S1 and O exhibit a Z conformation around the C10—C14 bond.

Synthèse et structure du tétrachloroplatinate(II) de pyrido[2,3-h]pyrrolo[1,2-a]quinoxalinium monohydrate, [C14H11N3][PtCl4].H2O

The structure of the title compound, 5H + ,8H + -pyrido[2,3-h]pyrrolo[1,2-a]quinoxalinium tetrachloroplatinate monohydrate, consists of a square planar (PtCl 4 ) 2- anion and a PPQH 2 2+ cation, where PPQH 2 + is the protonated organic ligand. The protonation on the N(5) and N(8) atoms gives rise to an opening of the angles C(4)-N(5)-C(14) and C(9)-N(8)-C(15) when compared with the homologous values in the neutral PPQ form. Although each ring of the PPQH 2 2+ ion is almost planar to within experimental error, the ion as a whole is not, as shown by the value of the dihedral angle [18.8 (2) o ] between the mean planes of the pyrrole (P1) and the pyridine (P4)

An original linkage between arabinose and a pyranopyrimidine derivative via a sulfur atom

The structure of 5-methyl-2-[(2,3,4-tri-O-acetyl-β-D- arabinopyranosyl)thio]-3,4-dihydro-7H-pyrano[2,3- g]pyrimidine-4,7-dione, C 19 H 20 N 2 O 10 S, is described. This compound consists of a sugar ring and a planar base (pyranopyrimidine derivative) linked unusually by an S atom. The sugar ring is in a 4 C 1 chair conformation and makes dihedral angles of 74.5 (4) and 75.7 (4) o with the pyran and pyrimidine rings. The S atom occupies an axial position on the sugar ring and lies 2.461 (9) A out of the corresponding mean plane