Reinaldo Atencio
Venezuelan Institute for Scientific Research
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Reinaldo Atencio.
Inorganic Chemistry | 2001
Maribel Navarro; Efrén J. Cisneros-Fajardo; Teresa Lehmann; Roberto A. Sánchez-Delgado; Reinaldo Atencio; Pedro Silva; Renee Lira; Julio A. Urbina
The complexes [Cu(CTZ)(4)]Cl(2).2H(2)O (1), [Cu(CTZ)Cl(2)](2) (2), [Cu(KTZ)(3)Cl(2)] (3), and [Cu(KTZ)Cl(2)](2).2H(2)O (4) were prepared by reaction of CuCl(2) with CTZ and KTZ (where CTZ = 1-[[(2-chlorophenyl)diphenyl]methyl]-1H-imidazole and KTZ = cis-1-acetyl-4-[4-[[2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethyl)-1,3-dioxolan-4-yl]methoxy]phenyl]piperazine), respectively, in acetonitrile at different ligand to metal molar ratios. Gold complexes [Au(PPh(3))(CTZ)]PF(6) (5) and [Au(PPh(3))(KTZ)]PF(6).H(2)O (6) were synthesized by reaction of AuClPPh(3), with KPF(6) and CTZ or KTZ in acetonitrile. All the new compounds were characterized by NMR spectroscopy and microanalytical methods, and for the paramagnetic species EPR spectroscopy and DC magnetic susceptibility measurements were also employed. The solid-state structure of 1 has been determined by X-ray crystallography. 1 crystallizes in the triclinic space group P(-)1, with a = 12.773(2) A, b = 15.326(4) A, c = 11.641(2) A, V = 1957.4(7) A(3), Z = 1, and D(calcd) = 1.284 g/cm(3). The structure refinement converged at R1 = 0.0731 and wR2 = 0.1962. Complex 1 displayed a square-planar structure typical for tetrakis(imidazole)copper(II) complexes. The new compounds were tested for in vitro activity against cultures of epimastigotes of Trypanosoma cruzi, the causative agent of Chagas disease. At concentrations equivalent to 10(-6) M of total CTZ or KTZ (in DMSO) all the complexes exhibited significantly higher growth inhibitory activity than their respective parental compounds.
Chemical Communications | 2006
Alexander Briceño; Dayana Leal; Reinaldo Atencio; Graciela Díaz de Delgado
An unprecedented example of supramolecular isomerism based on 2D hydrogen-bonded multi-component networks that leads to the preparation of different photoproducts via a topochemical transformation is reported.
Inorganica Chimica Acta | 1998
Roberto A. Sánchez-Delgado; Maribel Navarro; Keyla Lazardi; Reinaldo Atencio; Mario V. Capparelli; Franklin Vargas; Julio A. Urbina; André Bouillez; Alfred F. Noels; Dante Masi
Abstract The syntheses and characterization of metal imidazole complexes showing activity against Trypanosoma cruzi, the causative agent of Chagas disease, are presented, RuCl2(CTZ)2 (2) and RuCl2(BTZ)2 (4) were prepared by reaction of RuCl2(NCCH3)4 (1) with the appropriate ligand (CTZ, clotrimazole = 1-[(2-chlorophenyl)diphenylmethyl]-1H-imidazole; BTZ = 1-[(2-bromophenyl)diphenylmethyl]-1H-imidazole) [Ru(bipy)(CTZ)2](PF6)2 (3) (bipy=2,2′-bipyridyl) was obtained by reaction of 2 with bipy and NH4PF6 in MeCN. Reaction of [RhCl(COD)]2 with CTZ yielded RhCl(COD)(CTZ) (5) (COD=1,5-cyclooctadiene), while AuCl1CTZ (6), K2[PtCl4(CTZ)2] (7) and [Cu(CTZ)2]PF6 (8) were obtained by interaction of CTZ with AuCl1·HCl, K2PtCl4 and [Cu(CH3CN)4]PF6, respectively. All the new complexes were characterized by NMR and other appropriate techniques, X-ray diffraction studies of 4·3H2O, 5 and 6 were also carried out. The structure of 4·3H2O consists of a distorted tetrahedral arrangement of two N atoms from the BTZ ligands and two Cl atoms around the Ru(II) ion; 4·3H2O crystallizes in the orthorhombic space group Puma (No. 62) with a=12.818(5), b=29.115(5), c=12.040(5) A , V=4493.2(8) A and Z=4. Complex 5 displayed a square planar structure typical for Rh(1) bound to N from CTZ, Cl, and the two CC bonds of COD; 5 crystallized in the triclinic space group (P(= l) (No. 2) with a=12.407(3), b=12.876(4), c=10.069(3) A , α=111.59(2)°, β=107.80(2)°, γ=103.28(2)°, V=1313.4(8) A 3 and Z=2. Complex 6 also displayed a square arrangement of N from CTZ, plus three Cl atoms around the Au(III) ion; 6 crystallized in the monoclinic space group P21/n (No. 14) with a=9.507(1), b=18.280(4), c=12.877(1) A , β=100.59(1)°, V=2199.7(5) A 3 and Z=4. All the new compounds were found to be active against in vitro cultures of Trypanosoma cruzi, following the trend 3 = 7
Chemical Communications | 2005
Reinaldo Atencio; Alexander Briceño; Xacvier Galindo
The mesoporous H-bonded organic-inorganic hybrid material is built up from the assembly of the isopolymolybdate [Mo36O112(OH2)16]8- and H2bipy2+, which displays large interconnected cavities and exhibits a reversible water sorption behaviour while maintaining its striking crystal integrity.
New Journal of Chemistry | 2007
Reinaldo Atencio; Alexander Briceño; Pedro Silva; José A. Rodriguez; Jonathan C. Hanson
The new hybrid inorganic–organic solids [Mo8O26][H2bpe]2 (1), {[Mo8O26(μ-bpe)][H2bpe]2}n (2), [Mo8O26(Hbpe)2][H2bpe] (3), and {[Mo8O26][H2bpe]2}n (4) were synthesized under hydrothermal conditions. The crystal structure of 1 contains the discrete octamolybdate β-isomer, whereas in 3 the inorganic building unit is a functionalized octamolybdate of general formula [Mo8O26X2](2n+4). A similar building unit is found in 2 and 4, but forming part of polymeric 1D-arrays. In 2 the polymer is constructed from [Mo8O26(μ-bpe)]4−, and the functionalization of the anionic cluster in 4 occurs through Mo–O–Mo bonds. The sequential hydrothermal 2/3 → 1 and 1 → 4 transformations were observed at 145 and 180 °C, respectively. However, thermal studies of 1 and 4 revealed that both materials do not suffer any phase transitions below 340 °C for 1 or <350 °C for 4, indicating that such transformations are possible only under the hydrothermal conditions. An XRPD study as a function of the temperature of 1 also demonstrated the negligible structural changes before 330 °C.
New Journal of Chemistry | 2001
Briccyle Cova; Alexander Briceño; Reinaldo Atencio
The synthesis and crystal structure of a novel silver(I) mesoporous material are reported. The crystal structure is built from two different 1-D metal-based assemblies. A discrete [Ag(HIso)(Iso)] (HIso = isonicotinic acid) complex assembled via charge-assisted O⋯H⋯O hydrogen bonds co-exists with a [Ag(Iso)]n co-ordination polymer. Both 1-D arrays are essentially sustained together through π–π and Ag⋯O intermolecular interactions. This crystal structure is an illustrative example of an unusual harmonisation of different metal-based assemblies to achieve a new supramolecular architecture.
CrystEngComm | 2002
Karina Ramírez; Julián A. Reyes; Alexander Briceño; Reinaldo Atencio
A supramolecular building block II is recognized from the crystal structure of compound [(H3biim)+(Cl−)]·H2O (H2biim = 2,2′-biimidazol) (1), in which a Cl− is linked to a (H3biim)+ cation via symmetrical N–H⋯Cl− hydrogen bonds, as the remaining N–H groups of the (H3biim)+ connect with another [(H3biim)+(Cl−)] fragment to form the final dimeric unit II. The self-assembly of II through C–H⋯Cl− hydrogen bonds leads to an extended 2D-array with cavities. The stacking of these layers allows the formation of channels containing water molecules. The modular building blocks III and IV, observed in the previously reported crystal structures of [(H3biim)+(I−)·(H2biim)] (2a) and [(H4biim)2+(Cl−)2] (3b), show the same sort of hydrogen-bonded 2D-network as that found in 1, but with a dramatic change in the dimensions of the cavities.
New Journal of Chemistry | 1999
Reinaldo Atencio; Lee Brammer; Shiyue Fang; F. Christopher Pigge
Metal–arene complexes with suitable substituents on the π-bound arene represent a new class of organometallic building blocks for use in supramolecular chemistry. They provide a conceptually versatile avenue for construction of discrete assemblies and extended arrays, as is illustrated by the examples presented in which assembly occurs via hydrogen-bonded connections between carboxyl substituents.
Journal of Coordination Chemistry | 2009
J.R. Anacona; Daniel Loroño; Mary Azocar; Reinaldo Atencio
The preparation, spectroscopic properties and crystal structure of [pyrrolidinium][Co(sulfathiazole)3(pyrrolidine)] are reported. The X-ray structure reveals tetrahedral geometry around cobalt. Three sulfathiazole ligands (each in a κ,N-binding mode) occupy three positions, while the remaining position is occupied by a disordered pyrrolidine. A pyrrolidinium is also disordered. The superoxide dismutase mimetic activity of the complex was investigated using the indirect xanthine-xanthine oxidase-nitroblue tetrazolium method and compared to that of the native enzyme.
Dalton Transactions | 2004
Reinaldo Atencio; Mirbel Chacn; Teresa Gonzlez; Alexander Briceo; Giuseppe Agrifoglio; Anibal Sierraalta
A robust heteromeric hydrogen-bonded synthon [R2(2) (9)-Id] is exploited to drive the modular self-assembly of four coordination complexes [M(H2biim)2(OH2)2]2+ (M = Co2+, Ni2+) and carboxylate counterions. This strategy allowed us to build molecular architectures of 0-, 1-, and 2-dimensions. A hydrogen-bonded 2D-network with cavities has been designed, which maintains its striking integrity after reversible water desorption-resorption processes.