Showing papers by "Oscar E. Piro published in 1997"
TL;DR: In this article, it was shown that the frequency downshifts of vibrational modes of the RuNO group are far larger than shifts of CN modes, a fact that indicates that the metastable states involve electronic transitions mainly located at that group.
39 citations
TL;DR: In this paper, the structure of Mn[Fe(CN)5NO·2H2O, obtained by slow interdiffusion of reactant solutions through a TMS gel, was solved by X-ray diffraction methods and refined toR1=0.036.
Abstract: The single crystal and anion structure of Mn[Fe(CN)5NO·2H2O, obtained by slow interdiffusion of reactant solutions through a TMS gel, was solved by X-ray diffraction methods and refined toR1=0.036. Spatial group: orthorhombic,Pnma,a=14.069(2),b=7.538(1),c=10.543(1)A,Z=4. The Mn(II) ion and the water molecules are sited on mirror planes, which bisect the nitroprusside ions. One of the water molecules is coordinated to Mn(II) and the other, strongly hydrogen (as acceptor) bonded to the first molecule. The IR spectrum confirms the bonding of the water molecules and TGA results are in accordance with the dihydrate character of the substance and its dehydration in two successive steps. DTA results and the Raman spectrum agree with other results and the comparison between IR and RamanvNO wavenumbers confirms the expected strong vibrational interaction between the closely packed antiparallel (eclipsed) NO groups. There is a topotactic relationship between the dihydrate and the trihydrate, which crystallizes in the space subgroupP2
1/n.
24 citations
TL;DR: In this paper, the crystal structure of the little compound has been solved by single-crystal X-ray diffractometry, where the CuII ion is located on a two-fold crystallographic axis in a quasi-tetrahedral coordination.
23 citations
TL;DR: In this article, a rhenium(III) complex, [Re(SC(NH2)2)6]3+, has been prepared by reduction of perrhenate with tin chloride in strongly acidic solution in the presence of thiurea.
14 citations
TL;DR: The title compound (NH4)2[VO(C3H2O4]2]·2H 2O, crystallized in the monoclinic space group P21/n, with a=7.1889(7), b=19.254(2), c=9.879(2) A, β=108.19(1)o, and Z=4.
Abstract: The title compound, (NH4)2[VO(C3H2O4)2]·2H2O, crystallizes in the monoclinic space group P21/n, with a=7.1889(7), b=19.254(2), c=9.879(2) A, β=108.19(1)o, and Z=4. The VO2+ cation is five-fold coordinated with two malonate anions acting as bidentate ligands and a water molecule. Infrared and Raman spectra are also reported to attain a wider insight into the compound characteristics.
13 citations
TL;DR: In this paper, the title compound, [Cu(N3)(NCO)(C6H16N2)]2, was crystallized in the space groupP21/n, witha=8.336(1),b=17.405(3),c= 8.376(1) A, β=109.73(2)o andZ=4.93(1).
Abstract: The title compound, [Cu(N3)(NCO)(C6H16N2)]2, crystallizes in the space groupP21/n, witha=8.336(1),b=17.405(3),c=8.376(1) A, β=109.73(2)o andZ=4. The molecules are arranged as centrosymmetric dimers in which two azide ligands bridge neighboring copper ions in an asymmetric head-on fashion. The Cu(II) ion is coordinated to five nitrogen atoms which form a distorted tetragonal pyramid. At the pyramid base are the two N atoms of a diEten molecule [Cu−N=2.00(1), 2.130(9) A], an azide end atom [Cu−N=1.99(1) A] and a NCO group [Cu−N=1.93(1) A]. At the pyramid apex is the other, inversion related, azide N atom in the dimer [Cu−N=2.38(1) A]. This Cu−N contact links the monomers within a dimer. Neighboring dimers are coupled by weak N−H…O contacts. Single crystal EPR data at X-band show that the pair of resonances expected for neighboring, magnetically nonequivalents dimers, collapse into a single line, a signature of inter-dimers superexchange coupling. The observed crystal gyromagnetic tensor is used to disclose the electronic and magnetic structure around Cu(II) ions.
3 citations