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Synthesis, X-ray crystal structure and IR spectrum of {[MnII(Im)6] AE 2(2-IC) AE 2(NC) AE 2(DMSO)} (Im = imidazole, 2-HIC = indole-2- carboxylic acid, NC = 2,9-dimethyl-1,10-phenanthroline, DMSO = dimethyl sulfoxide) are reported. The manganese(II) ion has octahedral geometry with a MnN6 core. The crystal structure is completed by two NC, two 2-IC- and two DMSO solvate molecules. The individual cations are linked into chains running parallel to the a axis by four intermolecular hydrogen bonding involving two 2-IC-solvate. Moreover, these chains are connected by p–p stacking interactions which occur between neocuproine molecules related through inversion center. In IR spectroscopy, the compound spectrum is roughly similar to the imidazole one: (i) above 1800 cm1, the bands are broad, but when focussing on some of them a doublet structure can be found; (ii) below 1800 cm1, the bands are sharp and it is then possible to point out the modification of S–O band when this later is involved in bifurcated hydrogen bonding to a second solvate 2-IC-. The compound catalyses the disproportionation of H2O2; moreover an additional quantity of imidazole increases the reaction rate.

Three ternary complexes of zinc indole-2-carboxylate (2-IC) with 2,9-dimethyl-1,10-phenanthroline (NC) in dimethylacetamide (DMA), dimethylformamide (DMF) or dimethyl sulfoxide (DMSO) were synthesized, their X-ray crystal structure and IR spectra were determined. In compound [Zn(2-IC)2(NC)]·(DMA) (1), Zn is five-coordinate by one bidentate NC ligand and two 2-IC anionic ligands one of which is monodentate, and the other is bidentate. The individual molecules are linked into chains running parallel to the a-axis by intermolecular hydrogen bonding. The crystal structure is completed by a DMA solvate molecule. Compounds [Zn(2-IC)2(NC)]·(DMF) (2) and [Zn(2-IC)2(NC)]·(DMSO) (3) contain one monomeric zinc complex similar to 1 and a disordered solvate molecule (DMF in 2; DMSO in 3) in contrast to 1. In the IR spectra of the three compounds, the most important feature is the appearance of a very broad band at about 3175 cm−1 presenting a fine structure which can be correlated to hydrogen bonds in N–H⋯O bifurcated links, via inter and intramolecular interactions. A tentative assignment was made to point out the bidentate or monodentate carboxylate groups attached to the Zn atom.

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.

The asymmetric unit of the title compound, [Zn(C7H5O3)2(C10H8N2)], contains one monomeric zinc complex. The Zn atom is coordinated to one 2,2′-bipyridyl ligand via both N atoms and to two salicyl­ate anions (Hsal−) in a bidentate chelating manner involving carboxyl­ate O-atom coordination. The complex exhibits a distorted octahedral geometry about the ZnII atom, with the `apical' positions occupied by one of the two N atoms of the bipyridyl ligand and an O atom from one Hsal− ligand; the Zn atom is 0.168 (1) A out of the `basal' plane. Two intramolecular six-membered hydrogen-bonded rings are present, generated from interactions between the carboxyl and hydroxyl groups of the salicyl­ate ligands. The crystal packing is governed by weak C—H⋯O and C—H⋯π interactions.

Study by X-ray diffraction of various mixtures of CaS and Yb 2 S 3 after heating at 1200 °C, reveals the existence of continuous domains of solid solutions with successively a NaCl-type cubic unit cell (parameter a), a cubic unit cell (parameter 2a) and a rhombohedral structure. Some of the structures have been determined by three dimensional X-ray diffraction. Ca 3.86 Yb 0.09 S 4 [a = 5.691A, Fm3m] and Ca 3.10 Yb 0.60 S 4 [a = 5.675A, Fm3m] have a rock salt structure. In Ca 2.30 Yb 1.14 S 4 [a = 11.246A, F43m], Ca and Yb are in the same octahedral (24f) sites; octahedral (4c) and (4d) positions are occupied respectively by Ca and Yb atoms. The order of the cations in the 〈111〉 planes accounts for the superstructure.

In the ternary Yb-In-S system two phases were identified and their structure determinated on single crystal by X-ray diffraction. Yb[sub 4/3]In[sub 4/3]S[sub 4] belongs to a solid solution, it has a cubic structure intermediate between spinel and NaCl type. All metal sites are incompletely occupied. Yb[sub 18]In[sub 7.33]S[sub 36] is hexagonal. Yb[sup III] atoms have two types of environment with sevenfold prismatic and sixfold octahedral coordination. However, the octahedral sites are occupied also by In[sup III] atoms. Large channels around the threefold and sixfold axes are occupied by In[sup 1] or are empty. The two structures are analyzed. They have the particularity to have octahedral sites occupied by Yb[sup III] and In[sup III] statistically disordered. The most similar radii of Yb[sup III] and In[sup III] atoms are likely the reason of the existence of the hexagonal phase not found for other rare earth atoms and also of the presence of a large solid solution, domain for the first phase.

The title compounds are characterized by powder XRD and magnetic measurements in the temperature range 5—300 K.

The asymmetric unit of the title compound, bis(μ-2-hydroxybenzoato-O 1 ,O 2 :O 2 )bis[(2,2'-bipyridyl-N,N')copper(II)]-acetylsalicylic acid-water (1/1/2), [Cu 2 (C 7 H 4 O 3 ) 2 (C 10 H 8 N 2 ) 2 ].C 9 H 8 O 4 .2H 2 O, contains a binuclear copper complex, one acetylsalicylic acid molecule and two water molecules. Both crystallographically independent Cu II atoms of the mixed binuclear unit show analogous distorted elongated square-pyramidal coordination (of the type 4+1). Each Cu II atom is surrounded by one 2,2'-bipyridyl chelate and two salicylate anions. The crystal packing is characterized by several intermolecular hydrogen bonds.

Cristallisation dans Pmma avec a=13,308, b=7,769, c=6,285 A, z=4; affinement jusqu'a R=0,0393. ZnTm 2 S 4 cristallise dans la structure olivine. Les atomes Tm III sont en coordination octaedrique (Tm-S=2,671 a 2,744 A) les atomes Zn I I sont dans des sites tetraedriques (Zn-S=2,294 a 2,388 A). Les distorsions des polyedres de coordination octaedrique et tetraedrique sont discutees

International audience; X-ray crystallography, infrared absorption and Raman scattering were applied to study the influence of Zn(II) or H+ on the amidic bond. (R,R)-1,2-diacetamidocyclohexane (DAACH) was chosen as a conformationally strained chiral building block including two amide bonds; this model is hoped to be not too far from a peptide and gives easily crystalline complexes. Crystallographic structures of DAACH molecule (1), DAACH/ZnBr2 (2) and DAACH/HBr3 (3) complexes were studied. Complexation of Zn by DAACH is due to the hyperpolarization of the amidic bond. IR and Raman studies of 1-3 agree with the X-ray results. This could be a model in the study of metal/proteins interactions or acidic denaturation of polypeptides

The title compound, tris[(R)-2-hydroxypropanamide-kappa2O,O']zinc(II) tetrabromozincate, [Zn(C3H7NO2)3][ZnBr4], contains one monomeric six-coordinate zinc complex cation and one tetrahedral [ZnBr4]2- anion. Both Zn(II) atoms lie on threefold axes. Coordination in the cation occurs via the amide and hydroxy O atoms [Zn-O = 2.074 (5) and 2.073 (6) A] and has a distorted octahedral geometry, with cis-O-Zn-O angles in the range 76.2 (2)-109.2 (2) degrees . In the crystal structure, the cations and anions are linked by N-H...Br and O-H...O hydrogen bonds, generating a three-dimensional network.

Two types of coordination polyhedra are present. The prismatic positions are occupied by Yb atoms. Yb and Fe atoms lie on octahedral sites with the same occupancy factor, and without any tendency to statistical disorder. Fe is divalent and Yb trivalent. The structure consists of prismatic rows along the a axis linked by ribbons of octahedral sites

The Yb and Ca atoms have slightly distorted octahedral environments and the K atom has regular sixfold prismatic coordination. The sites are completely (Yb, Ca) or partially (Yb, K) occupied. The compound crystallizes with a layer structure; each layer is made up of [CaS 6 ] or [YbS 6 ] octahedra and is perpendicular to the c axis. Groups made up of three layers, [Yb(1)S 6 ], [CaS 6 ] and [Yb(2)S 6 ], are held together by K atoms

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

The Yb atoms occupy independent, slightly distorted octahedral sites. All the metal sites are fully occupied. The structure consists of pairs of [YbS 6 ] octahedra forming chains parallel to the axis. In this direction, between two pairs of octahedra, there is an empty octahedral site. The compound may also be described as a layered structure; each layer is alternately composed of Yb and S atoms

The asymmetric unit of the title compound, [Zn(C(10)H(6)NO(2))(2)(C(12)H(8)N(2))] x 1.5C(3)H(7)NO, contains one monomeric zinc complex and 1.5 disordered dimethylformamide solvate molecules. The Zn atom is coordinated to one 1,10-phenanthroline ligand and to two isoquinolinecarboxylate anions (IQC-) via their N and O atoms. The complex exhibits a distorted octahedral geometry around the Zn(II) atom, with the apical positions occupied by the O atoms of the IQC- ligands. The Zn atom lies 0.049 (1) A out of the basal plane. The crystal packing is characterized by several hydrogen bonds.

The asymmetric unit of the title compound, [CuCl(C(10)H(6)NO(2))(C(14)H(12)N(2))], contains two monomeric copper molecules, A and B. Each Cu atom is coordinated to one 2,9-dimethyl-1,10-phenanthroline (neocuproine) ligand via both N atoms, to one isoquinoline-1-carboxylate anion (IQC(-)) via the N and one O atom, and to one Cl(-) anion. The environment of the Cu atom is approximately square pyramidal, with the apical position occupied by an N atom of neocuproine. In molecule A, the Cu atom is 0.301 (1) A above the basal plane; this distance is 0.316 (1) A in molecule B. The crystal packing is characterized by several hydrogen bonds.

Cristallisation dans Bb2 1 m avec a=12.55, b=12.74, c=3.756A, affinement jusqu'a R=0.05. Les sites octaedriques sont occupes selon un desordre statistique par des ions divalents Mn et des ions divalents et trivalents Yb. Seuls les ions trivalents Yb occupent des sites prismatiques

The electrochemistry of trimetallic ‘crown-like’ iridium(I) complexes of the type Ir 3 (μS- t Bu) 3 (μX)(CO) 6 [X = F 3 CCCCF 3 (1), H 3 COOCCCCOOCH 3 (2)] and substituted analogues Ir 3 (μS- t Bu) 3 (μX)(CO) 5 L [X = F 3 CCCCF 3 , L = C 4 F 6 (3), CH 3 CN (4)] has been studied in CH 3 CN and CH 2 Cl 2 solvents on mercury, platinum and glassy carbon electrodes. These complexes undergo an irreversible one-electron reduction leading to the destruction of the trimetallic units. An irreversible one-electron oxidation step is also observed. A redox mechanism is proposed on the basis of electrochemical and IR spectroscopic results by comparison with the electrochemical behavior of the analogous dimetallic [Ir(μS- t Bu)(CO) 2 ] 2 (5).

Cristallisation dans P6 3 /m avec a=20,688 et c=3,861 A, Z=1; affinement jusqu'a R=0,053. Les atomes Yb (III) ont deux types d'environnement: coordination prismatique d'ordre 7 et octaedrique d'ordre 6. Toutefois, les seconds sites sont egalement occupes par In (III). De grands canaux autour des diols d'ordre 3 et d'ordre 6 sont respectivement occupes par In (I) et vides

A description of the presently known crystal structures of ternary sulfides containing europium is presented. Most of them are formed by divalent europium; they are divided into three classes: Classical structures , in which each cation is bonded to S and each S anion is simultaneously bonded to the two metals: M 1− x Eu x S (M ≡ Ca, Sr, Ba); R 2 EuS 4 (R ≡ trivalent rare-earth ion); EuGa 2 S 4 , Eu 2 GeS 4 , Eu 3 Ge 3 S 9 , Eu 3 Sn 2 S 7 , Eu 3 Sb 4 S 9 , Eu 1− x Cr 2 S 4− x and Eu p NbS 2 . The usual coordinations of Eu(II) in these compounds are 7–8 in mono- or dicapped trigonal prisms, 8 in square prisms. Cluster structures , observed with clusters of the second metal: EuMo 6 -S 8 (Chevrel phase), Eu 2 Re 6 S 11 or polysulfide groups: Eu 2 SnS 5 . Semi-metal structures : Eu 1.1 Bi 2 S 4 , for which some Eu(II) atoms are in semi-metallic channels. In these non-classical structures, the coordination polyhedra of Eu(II) are often strongly modified. Trivalent europium is present in MEuS 2 compounds (M ≡ IA elements), with an octahedral coordination. Mixed-valence compounds are Eu 5 Sn 3 S 12 , Eu 2 BiS 4 and Eu 2 CuS 3 . The sites of Eu(II) and Eu(III) are well differentiated in their structures and these compounds are, in reality, quaternary compounds.

The thermal behaviour of decacarbonyldirhenium has been investigated. A reversible crystalline phase transition appears at 92 °C in all atmospheres studied: nitrogen, air, argon, and oxygen. A Debye–Scherrer X-ray diffraction diagram of the new crystalline phase is submitted, and an interpretation of the transition is suggested.