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Abstract: The novel complex, C(NH2)3[VO2(dipic)]·2H2O (1), and its analogous, NH4[VO2(dipic)] (2), were synthesized and characterized in the solid state by means of FT-Raman and FT-infrared spectroscopies. Their crystal and molecular structures were determined by X-ray diffraction methods. The optimized geometry of the [VO2(dipic)]− anion and its corresponding harmonic vibrational frequencies were calculated using methods of the density functional theory. The [VO2(dipic)]− anion in both salts show a similar penta-coordinated environment. The planar dipic2− ligand coordinates to the moiety through one oxygen of each carboxylate and the nitrogen atom. Slight but significant differences between the bonding structures in both compounds were observed. The crystal structures are stabilized by hydrogen bridging interactions. [Copyright &y& Elsevier]

Abstract: Pure O-methyl N-methoxycarbonyl thiocarbamate CH3OC(S)N(H)C(O)OCH3 (I) and O-ethyl N-methoxycarbonyl thiocarbamate, CH3CH2OC(S)N(H)C(O)OCH3 (II), are quantitatively prepared by the addition reaction between the CH3OC(O)NCS and the corresponding alcohols. The compounds are characterized by multinuclear (1H and 13C) and bi-dimensional (13C HSQC) NMR, GC–MS and FTIR spectroscopy techniques. Structural and conformational properties are analyzed using a combined approach involving crystallographic data, vibration spectra and theoretical calculations. The low-temperature (150K) crystal structure of II was determined by X-ray diffraction methods. The substance crystallizes in the monoclinic space group P21/n with a =4.088(1)Å, b =22.346(1)Å, c =8.284(1)Å, β =100.687(3)° and Z =4 molecules per unit cell. The conformation adopted by the thiocarbamate group –OC(S)N(H)– is syn (Cbond in synperiplanar orientation with respect to the N–H single bond), while the methoxycarbonyl Cbond is in antiperiplanar orientation with respect to the N–H bond. The non-H atoms in II are essentially coplanar and the molecules are arranged in the crystal lattice as centro-symmetric dimeric units held by N−H···Sn bonds [d(N···S)=3.387(1)Å, ∠(N−H···S)=166.4(2)°]. Furthermore, the effect of the π electronic resonance in the structural and vibrational properties is also discussed. [Copyright &y& Elsevier]

Abstract: The synthesis and characterisation by solid-state 111Cd NMR of Cd(2,3-), Cd(2,4-), Cd(2,5-) and Cd(2,6-pyridinedicarboxylato)· xH2O is reported. Results indicate that the 111Cd NMR signal is very sensitive to the relative position of both carboxylates. Similar shifts (at 54.0 and 55.4ppm) are found for the 2,4- and the 2,6-isomers where the carboxylates groups are meta to each other. For the 2,3- and 2,5-derivatives (carboxylates in ortho and para positions), the signals are detected at 119.6 and 84.2ppm. The crystal and molecular structure of the seven-coordinated cadmium complex, [Cd(2,4-pyridinedicarboxylato)(H2O)3]·1/2H2O is also reported. This data allows a correlation between Cd–O and Cd–N coordination and geometry with 111Cd chemical shifts. Additional coupling between 111Cd and 14N in 2,3- (also found in 2,4-pydc) suggests only one N is coordinated to Cd. The anisotropy magnitude, Δσ, and the asymmetry parameter, η, are also analysed. [Copyright &y& Elsevier]

The crystal structure of nitropentaamminecobalt(III) nitroprusside sesquihydrate, [Co(NH3)5NO2][Fe(CN)5NO]·1.5H2O has been determined by Patterson and Fourier methods employing 3881 independent X-ray reflections with I>2σ(I) and refined by full-matrix least-squares to R1=0.032. The substance crystallizes in the monoclinic C2/c (C2h6) space group No. 15, with a=28.408(3), b=6.422(1), c=22.401(3) A˚, β=123.55(1)° and Z=8. The metastable state I (MSI) of the nitroprusside anion and the photochemical isomerization reaction of the nitropentaamminecobalt(III) cation to the nitrito isomer were produced by irradiation with Ar+ laser light of 488 nm wavelength at 77 K. TGA and DTA of the non-excited substance were performed under nitrogen atmosphere. [Copyright &y& Elsevier]

The crystal structure of Ba(NH4)[Co(CN)6]·4H2O complex was determined by X-ray diffraction methods. It crystallizes in the hexagonal P63/m space group with a = b =7.6882(2)Å, c =14.4764(4)Å, and Z =2 molecules per unit cell. The structure was solved from 475 reflections with I >2σ(I) and refined to an agreement R1-factor of 0.0214. The cobaltocyanide anion has an octahedral shape with its Co(III) ion sited at a crystallographic special position of point symmetry (S 6) [d(Co-C)=1.886(3)Å and d(C–N)=1.143(4)Å]. The barium ion is in a 9-fold environment at a crystal special position (C 3 h ), coordinated to cyanide N-atoms of neighboring complexes [d(Ba–N)=2.862(3)Å] and to one type of water molecule laying onto an m mirror plane [d(Ba–Ow)=2.924(4)Å]. The ammonium ion and the other type of water molecule share four symmetry-related C 3 lattice sites with equal occupancy. Under the P63 subspace group these four sites split into two independent pairs of C 3 sites, one occupied by two symmetry-related ammonium ions, the other by two (disordered) water molecules. The complex was characterized by UV–Vis, IR and Raman spectroscopy and the thermal decomposition was studied to investigate the formation of BaCoO3− δ . This compound, in its hexagonal form, could be synthesized at temperatures as low as 675°C. At 750°C a new orthorhombic poly-type is obtained in a mixture with the hexagonal form which is associated with the appearance of oxygen vacancies. These temperatures of synthesis and reaction times are lower than those reported by ceramic and sol–gel synthesis. These soft treatments gave rise to homogeneous particles of small grain size. [ABSTRACT FROM AUTHOR]

Abstract: Complexes [Zn2(HL1)2(CH3COO)2] (1) and [Zn2(L2)2] (2) were synthesized with salicylaldehyde semicarbazone (H2L1) and salicylaldehyde-4-chlorobenzoyl hydrazone (H2LASSBio-1064, H2L2), respectively. The crystal structure of (1) was determined. Upon recrystallization of previously prepared [Zn2(HL2)2(Cl)2] (3) in 1:9 DMSO:acetone crystals of [Zn2(L2)2(H2O)2]·[Zn2(L2)2(DMSO)4] (3a) were obtained. The crystal structure of 3a was also determined. All crystal structures revealed the presence of phenoxo-bridged binuclear zinc(II) complexes. [Copyright &y& Elsevier]

Abstract: The “Ru(P–P)” unit (P–P=diphosphine) is recognized to be an important core in catalytic species for hydrogenation of unsaturated organic substrates. Thus, in this study we synthesized six new complexes containing this core, including the binuclear complex [(dppb)(CO)Cl2Ru-pz-RuCl2(CO)(dppb)] (pz=pyrazine) which can be used as a precursor for the synthesis of cationic carbonyl species of general formula [RuCl(CO)(dppb)(N–N)]PF6 (N–N=diimine). Complexes with the formula [RuCl(py)(dppb)(N–N)]PF6 were synthesized by exhaustive electrolysis of these carbonyl compounds or from the precursors [RuCl2(dppb)(N–N)]. The new complexes were characterized by microanalysis, conductivity measurements, IR and 31P{1H} NMR spectroscopy, cyclic voltammetry and X-ray crystallography. [Copyright &y& Elsevier]