Bis{[amino-(iminium-yl)meth-yl]urea} tetra-kis-{2-[(di-methyl-amino)(iminium-yl)meth-yl]guanidine} di-µ6-oxido-tetra-µ3-oxido-tetra-deca-µ2-oxido-octa-oxidodeca-vanadium(V) tetra-hydrate.

The title compound, (C4H12N5)4(C2H7N4O)2[V10O28]·4H2O, is a by-product obtained by reacting ammonium metavanadate(V), metformin hydro-chloride and acetic acid in the presence of sodium hypochlorite, at pH = 5. The crystal structure comprises a deca-vanadate(V) anion (V10O28)6- lying on an inversion centre in space group P , while cations and solvent water mol-ecules are placed in general positions, surrounding the anion, and forming numerous N-H⋯O and O-H⋯O hydrogen bonds. Metforminium (C4H12N5)+ and guanylurea (C2H7N4O)+ cations display the expected shape. Inter-estingly, in physiology the latter cation is known to be the main metabolite of the former one. The reported structure thus supports the role of sodium hypochlorite as an oxidizing reagent being able to degrade metformin hydro-chloride to form guanylurea.

Tetra-ammonium bis-(metforminium) di-µ6-oxido-tetra-µ3-oxido-tetra-deca-µ2-oxido-octa-oxidodeca-vanadium(V) hexa-hydrate.

The title compound, (NH4)4(C4H12N5)2[V10O28]·6H2O, crystallizes with the deca-vanadate anion placed on an inversion centre in space group P . This anion is surrounded by a first shell of ammonium cations and water mol-ecules, forming efficient N-H⋯O and O-H⋯O hydrogen bonds. A second shell includes metforminium monocations with a twisted geometry, also forming numerous inter-molecular hydrogen bonds. The complex three-dimensional network of non-covalent inter-actions affords a crystal structure in which the cations and anions are densely packed.

Crystal structure of a new hydrate form of the NSAID sodium diclofenac.

The crystal structure is reported of sodium 2-[2-(2,6-di-chloro-anilino)phen-yl]acetate 3.5-hydrate or tetra-µ-aqua-κ8 O:O-deca-aqua-bis-{µ3-2-[2-(2,6-di-chloro-anilino)phen-yl]acetato-κ3 O:O:O}tetra-sodium(I) bis-{2-[2-(2,6-di-chloro-anil-ino)phen-yl]acetate}, {[Na4(C14H10Cl2NO2)2(H2O)14](C14H10Cl2NO2)2} n , which re-presents a new hydrate form of the NSAID sodium diclofenac (SD). The triclinic unit cell contains one ionic compound with formula Na4(C14H10Cl2NO2)4(H2O)14, in which two symmetry-related carboxyl-ate anions C14H10Cl2NO2 - are bonded to a centrosymmetric [Na4]4+ core cationic cluster, while the others are only hydrogen bonded to the cationic cluster. The conformation for the anions is similar to that found in other diclofenac compounds, and the [Na4(Ocarbox)2(H2O)14]4+ cluster displays an unprecedented geometry, which can be described as an incomplete dicubane cluster formed by face-sharing incomplete cubes. A complex framework of O-H⋯O hydrogen bonds stabilizes the crystal structure. The herein reported crystal structure for SD·3.5H2O in space group P is different from those previously reported for other hydrates, namely SD·4.75H2O (P21) and SD·5H2O (P21/m).

Redetermination of di-ammonium trivanadate, (NH4)2V3O8.

The crystal structure of (NH4)2V3O8 has been reported twice using single-crystal X-ray data [Theobald et al. (1984 ▸). J. Phys. Chem. Solids, 45, 581-587; Range et al. (1988 ▸). Z. Naturforsch. Teil B, 43, 309-317]. In both cases, the orientation of the ammonium cation in the asymmetric unit was poorly defined: in Theobald's study, the shape and dimensions were constrained for NH4 +, while in Range's study, H atoms were not included. In the present study, we collected a highly redundant data set for this ternary oxide, at 0.61 Šresolution, using Ag Kα radiation. These accurate data reveal that the NH4 + cation is disordered by rotation around a non-crystallographic axis. The rotation axis coincides with one N-H bond lying in the mirror m symmetry element of space-group type P4bm, and the remaining H sites were modelled over two disordered positions, with equal occupancy. It therefore follows that the NH4 + cations filling the space available in the (001) layered structure formed by (V3O8)2- ions do not form strong N-H⋯O hydrogen bonds with the mixed-valent oxidovanadate(IV,V) anions. This feature could have consequences for the Li-ion inter-calation properties of this material, which is used as a cathode for supercapacitors.

Synthesis, Kinetic Study, and Spectroscopic Analysis of Peroxidase-like Pinch-Porphyrin Fe(III) Complexes.

In the present manuscript, we report the kinetic and spectroscopic analysis of six new pinch-porphyrins: protoporphyrin-picpenta 1, mesoporphyrin-picpenta 2, deuteroporphyrin-picpenta 3, protoporphyrin-picocta 4, mesoporphyrin-picocta 5, and deuteroporphyrin-picocta 6. The Michaelis-Menten enzymatic pathway and the guaiacol test confirmed the ability of the compounds to function like new peroxidase models. UV-vis, 1H NMR, and electron spin resonance studies are in accordance with porphyrin-Fe(III) molecules with the quantum phenomena called quantum mixed spin (qms, s = 3/2, s = 5/2). Importantly, the influence of the presence of the s = 3/2 spin state in the compounds and its critical role for the catalytic capacity is proven here, which was the original hypothesis in our research group. The compounds with higher populations of the s = 3/2 spin state have increased peroxidase activity.

Does the compound hexaaqua-zinc(ii)bis(hydrogensulfate)dihydrate, [Zn(H2O)6](HSO4·H2O)2, really exist?

A careful examination of the crystal structure of the hydrogensulfate compound [Zn(H2O)6](HSO4·H2O)2 reported in this journal shows that the sample used for X-ray diffraction was almost certainly the Tutton salt [Zn(H2O)6](SO4·NH4)2, isoelectronic with the former elusive compound (F 000 = 416, P21/c space group). Indeed, any chemistry involving ammonium and sulfate moieties in an aqueous medium containing a transition metal cation should afford the corresponding Tutton salt as a by-product. We redetermined the structure of [Zn(H2O)6](SO4·NH4)2, on the basis of high-resolution X-ray data (d = 0.47 Å), with the purpose of illustrating that at such resolution, difference Fourier maps may be used to unambiguously differentiate between a sulfate and a hydrogensulfate ion. On the other hand, regardless of the data resolution, geometrical considerations may be enough to avoid misassignment of such small ions in crystal structures, providing that some knowledge about the average shape of these ions is available from curated crystallographic databases.

Crystal structure of r-1,c-2-dibenzoyl-t-3,t-4-bis-(2-nitro-phen-yl)cyclo-butane.

The condensation reaction of aceto-phenone (1-phenyl-ethan-1-one) with 2-nitro-benzaldehyde in the molten state yielded the expected chalcone, (E)-3-(2-nitro-phen-yl)-1-phenyl-prop-2-en-1-one, and, unexpectedly, the title compound, C30H22N2O6, which results from the syn head-to-head [2 + 2] cyclo-addition of the chalcone. The mol-ecular structure of the dimer shows that the four benzene rings of the substituents are oriented in such a way that potential steric hindrance is minimized, whilst allowing some degree of inter-molecular π-π inter-actions for crystal stabilization. In the mol-ecule, one nitro group is disordered over two positions, with occupancies for each part of 0.876 (7) and 0.127 (7).

Antioxidative stress effect of epicatechin and catechin induced by Aß25-35 in rats and use of the electrostatic potential and the Fukui function as a tool to elucidate specific sites of interaction.

Alzheimer's disease (AD) is a neurodegenerative disorder caused by the aggregation of the amyloid-beta peptide (Aß) in senile plaques and cerebral vasculature. The Aß25-35 fraction has shown the most toxicity; its neurotoxic mechanisms are associated with the generation of oxidative stress and reactive astrogliosis that induce neuronal death and memory impairment. Studies indicate that pharmacological treatment with flavonoids reduces the rate of AD, in particular, it has been shown that antioxidants are compounds that could interact with this peptide due to their antioxidant proprieties. In this study, experimental and computational tools were used to calculate the molecular electrostatic potential and the Fukui function with the Gaussian 09 computational program, to predict the most reactive parts of these molecules and make the complex between Aß25-35 and two flavonoids (catechin and epicatechin) in the absolute gas-phase, where a possible interaction between them was observed. This is important for understanding the Aß25-35-Flavonoid (A-F) interaction as a therapeutic strategy to inhibit the neurotoxic effects that this peptide causes in AD, which currently is still considered an ambiguous process.

Metforminium Decavanadate as a Potential Metallopharmaceutical Drug for the Treatment of Diabetes Mellitus.

New potential drugs based on vanadium are being developed as possible treatments for diabetes mellitus (DM) and its complications. In this regard, our working group developed metforminium decavanadate (MetfDeca), a compound with hypoglycemic and hypolipidemic properties. MetfDeca was evaluated in models of type 1 and type 2 diabetes mellitus, on male Wistar rats. Alloxan-induction was employed to produce DM1 model, while a hypercaloric-diet was employed to generate DM2 model. Two-month treatments with 3.7 µg (2.5 µM)/300 g/twice a week for DM2 and 7.18 µg (4.8 µM)/300 g/twice a week for DM1 of MetfDeca, respectively, were administered. The resulting pharmacological data showed nontoxicological effects on liver and kidney. At the same time, MetfDeca showed an improvement of carbohydrates and lipids in tissues and serum. MetfDeca treatment was better than the monotherapies with metformin for DM2 and insulin for DM1. Additionally, MetfDeca showed a protective effect on pancreatic beta cells of DM1 rats, suggesting a possible regeneration of these cells, since they recovered their insulin levels. Therefore, MetfDeca could be considered not only as an insulin-mimetic agent, but also as an insulin-enhancing agent. Efforts to elucidate the mechanism of action of this compound are now in progress.

Hypoglycemic, lipid-lowering and metabolic regulation activities of metforminium decavanadate (H2Metf)3 [V10O28]·8H2O using hypercaloric-induced carbohydrate and lipid deregulation in Wistar rats as biological model.

Because of the increasing global spread of type 2 diabetes mellitus, there is a need to develop new antidiabetic agents. Recently we have synthesized new decavanadates using metformin as counterion. In particular, the compound containing three metforminium dications has been obtained in high yield and has been completely characterized. Biological studies using Wistar rats that have been fed with a high caloric diet inducing insulin resistance and metabolic syndrome were carried out. Results of the impact on key biochemical parameters mediated by metformin alone and the new compound are here presented. The metforminium decavanadate (H2Metf)3[V10O28]·8H2O, abbreviated as Metf-V10O28, was shown to have pharmacological potential as a hypoglycemic, lipid-lowering and metabolic regulator, since the resulting compound made of the two components with antidiabetic activities, reduces both dosage and time of administration (twice a week). Hence, due to the beneficial effects induced by the metforminium decavanadate we recommend to continue the exploration into the mechanism and toxicology of this new compound.

2-Sulfanylidene-1,3-dithiolo[4,5-b]naphtho-[2,3-e][1,4]dithiine-5,10-dione.

The title mol-ecule, C(13)H(4)O(2)S(5), is folded by 47.83 (6)° along the S⋯S vector of the [1,4]dithiine six-membered ring, with the naphtho-quinone and [1,3]dithiole-2-thione moieties being nearly planar [largest deviations from least-squares planes = 0.028 (2) and 0.016 (1) Å, respectively]. This boat conformation is close to that observed in the analogous compound [Mendez-Rojas et al. (2001). J. Chem. Crystallogr.31, 17-28] including a 2-oxo group [folding angle: 42.3 (1)° at 213 (2) K]. Both compounds are indeed isomorphous, and the small difference in the folding angle probably results from the involvement of the thioxo group of the title compound in inter-molecular S⋯S contacts [3.5761 (13) Å]. In the crystal structure, mol-ecules are stacked in the [100] direction, with dithiole rings making π-π inter-actions. In a stack, alternating short and long separations are observed between the centroids of dithiole rings, 3.5254 (17) and 4.7010 (18) Å.

Experimental electron density study of tetrakis-mu-(acetylsalicylate)dicopper(II): a polymeric structure with Cu...Cu short contacts.

The electron density, its topological features, and the electrostatic potential of tetrakis-mu-(acetylsalicylate)dicopper(II), Cu[C(9)H(7)O(4)](2), have been derived from an accurate high-resolution diffraction experiment at 100 K. This complex exhibits a polymeric structure involving one acetyl oxygen atom as a bridge in the solid state. Only van der Waals interactions between the polymeric chains are observed. The copper cation is octahedrally coordinated with five oxygen atoms of the aspirinate ligands and one adjacent Cu with short Cu...Cu contact distances in the range of 2.6054(1) A. The Cu-O bond lengths are equal to 1.96 A except the apical one which is 2.2183(7) A. The multipole refinements were carried out using the Hansen-Coppens model coded in the MOPRO computer program. Starting from the 3d(10)4s(1) copper electron configuration, the electron density analysis and Cu d-orbital populations reveal that the observed configuration is close to being [Ar]3d(9)4s(1). As expected from the ligand field theory, the most depopulated 3d-orbital is the d(x(2)-y(2)) (1.17 e) one with lobes pointing toward the carboxylic oxygen atoms. Conversely, the d(z(2)) is the most populated orbital for a z-axis directed along the Cu...Cu bond. The atomic charges were derived from a kappa-refinement and yielded a metal net charge of +1.20(3) e. Deficits of +0.72(6) and +0.59(7) e are obtained for the acetyl carbon atoms of the aspirinate ligands, those involved in the drug activity of aspirin. Comparisons are made to the results of our previous work on the zinc-aspirinate complex.