Reinaldo Atencio

Toward a novel metal-based chemotherapy against tropical diseases. 6. Synthesis and characterization of new copper(II) and gold(I) clotrimazole and ketoconazole complexes and evaluation of their activity against Trypanosoma cruzi.

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.

Supramolecular isomerism in multivalent metal-templated assemblies with topochemical influence in the regioselective synthesis of tetrakis(2-pyridyl)cyclobutane isomers

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.

Toward a novel metal based chemotherapy against tropical diseases 4. Synthesis and characterization of new metal-clotrimazole complexes and evaluation of their activity against Trypanosoma cruzi

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 CC 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

A mesoporous hydrogen-bonded organic–inorganic framework bearing the isopolymolybdate [Mo36O112(OH2)16]8−

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.

Sequential transformations in assemblies based on octamolybdate clusters and 1,2-bis(4-pyridyl)ethane

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.

An unusual harmonisation of metal-based assemblies to achieve a mesoporous solid. Synthesis and crystal structure of a new silver(I) isonicotinate array

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.

Supramolecular building blocks from modular self-assembly of biimidazolium species. Crystal structure of 2-(2-1H-imidazolyl)-1H-imidazolium chloride monohydrate

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.

π-Bonded organometallic building blocks for supramolecular chemistry

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.

Synthesis, crystal structure and superoxide dismutase activity of [pyrrolidinium][Co(sulfathiazole)3(pyrrolidine)]

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.

Robust hydrogen-bonded self-assemblies from biimidazole complexes. Synthesis and structural characterization of [M(biimidazole)2(OH2)2]2+ (M = Co2+, Ni2+) complexes and carboxylate modulesElectronic supplementary information (ESI) available: TG/DSC analyses for compound 4. See http://www.rsc.org/suppdata/dt/b3/b312541f/

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.