Vicente Añó Sanz

Model compounds for the active sites of oxo-transfer molybdoenzymes. Synthesis, structural characterization, and electrochemical properties of [NH4]2[MoO2{O2CC(S)Ph2}2]

[NH4]2[MoO2{O2CC(S)Ph2}2]middot;2H2O has been prepared and its crystal structure solved, providing the first example of a co-ordinatively saturated molybdenum complex which reacts readily and reversibly with organophosphines at room temperature in water or methanol; its variable-temperature 13C{1H} NMR spectra and electrochemical properties are presented.

Poly(amine) biphenyl derivatives as fluorescent sensors for anions and cations

Four new ligands, derived from tetramethylbenzidine and containing additional amino groups, are described. The influence of pH on the fluorescent properties of these ligands has been studied, and the effect of the dihedral angle between the aromatic rings on the fluorescent response has been established. The behaviour of the new ligands, and that of others previously described in both the complexation and sensing of different anions and cations, are also described.

Molybdenum(VI)-dioxo complexes with sterically bulky thiocarboxylate ligands. Reactions with aliphatic thiols and electrochemical properties

Abstract Under acid conditions, the reaction of (Bu n 4 N)2[Mo VI O 2 (O 2 CC(S)Ph 2 ) 2 ] with aliphatic thiols yields the monomeric [Mo V O(O 2 CC(S)Ph 2 ) 2 ] − as unique complex product. The experimental pseudo-first order rate constant with respect to the Mo(VI) complex was found to be K =6.1 × 10 −5 s −1 . At neutral pH, however, an unstable Mo(IV) species was formed which was also electrochemically detected in a reversible Mo(V,IV) couple. [Mo V O(O 2 CC(S)Ph 2 ) 2 ] − appears to be obtained by the reaction of [Mo IV O(O 2 CC(S)Ph 2 ) 2 ] 2− with unreacted [Mo VI O 2 (O 2 CC(S)Ph 2 ) 2 ] 2− . Steric features on the ligand (gemdiphenyl groups) explain that the latter reaction does not lead to the expected formation of μ-oxo Mo(V) dimers. [Mo V O(O 2 CC(S)Ph 2 ) 2 ]− undergoes a one-electron reversible reduction on the cyclic voltammogram time scale, being also oxidized by nitrate ions to the starting Mo(VI) complex. The relation of these results to enzymatic systems is briefly discussed.

Polyazapodands Derived from Biphenyl. Study of their Behaviour as Conformationally Regulated Fluorescent Sensors

Eight new polyazapodands containing a 4,4′-substituted biphenyl moiety have been synthesised. Four (7, 8, 9 and 11) are functionalised on positions 4 and 4′ with a nitro group and four (1, 2, 3 and 10) with a dimethylamino substituent. Comparison of the emission behaviour of 1, 2, 3 with that of the reference compounds 10 and tetramthylbenzidine, clearly suggests that a modification in the dihedral angle between the biphenyl rings is an important factor in determining the fluorescent response of the molecule. The fluorescence is pH dependent, due to the formation of intramolecular hydrogen bonds between protonated aliphatic nitrogens and a carbonyl oxygen, which influences the aforementioned dihedral angle. A crystal structure resolved by X-ray diffraction of 7·2HCl has been determined, and confirms the dependence of the angle and the rigidity on the hydrogen bonding. The complexation properties of these ligands have been studied with Zn2+, Cd2+, Ni2+, Cu2+ and Pb2+, which show that the number of amino groups within the pendants has a strong influence on the nature of the complexation and the fluorescent response of each ligand.

Influence of cation size on the fluorescent properties of bis-coronand biphenyl-derived complexes

A new bis-coronand derived from biphenyl has been prepared and its complexing and sensing properties for alkaline, alkaline-earth and transition cations have been studied. Open and clamp complexes are formed depending on the cation size and complex stoichiometry. Both types of geometries can be distinguished due to their different fluorescent behaviour. Zn2+ gives rise to 1:1 and 1:2 complexes with a similar geometry.

[MoO2(SCPh2CO2)2]2− and [MoO(SCPh2CO2)2]− anion complexes. A theoretical structure characterization

Abstract Geometry optimization of [MoO 2 (SCH 2 CO 2 ) 2 ] 2− and [MoO(SCH 2 CO 2 ) 2 ] − systems as models of [MoO 2 (SCPh 2 CO 2 ) 2 ] 2− and [MoO(SCPh 2 CO 2 ) 2 ] − anion complexes have been carried out at STO-3G, 3-21G, LANL1MB and LANL2DZ basis set levels. A comparison of the theoretical results and X-ray experimental data has been performed. STO-3G minimal basis set produces the best geometrical agreement, in particular the distances and orientations of the different ligands linked to molybdenum transition metal. A large structural overlap with STO-3G optimized geometry and X-ray data has been found for the [MoO 2 (SCPh 2 CO 2 ) 2 ] 2− and [MoO(SCPh 2 CO 2 ) 2 ] − anion complexes.

ANÁLISE DA PERCEPÇÃO DOS RESIDENTES SOBRE O IMPACTO CULTURAL E DESPORTIVO DE UM GRANDE PRÊMIO DE FÓRMULA 1

The aim of this study is to analyze the resident’s perception about the cultural and sport impact of European Formula 1 Grand Prix. Cluster analysis was performed by combining hierarchical and non-hierarchical methods, which allowed us to differentiate three groups with different perceptions towards sporting event: Unfavorable, Moderate Unfavorable and Moderate Favorable. Most residents believe that this event has no significant impact to cultural and sporting level. Also, differences were found between the three groups of residents in the interest of Formula 1, the support for the event, attendance and the degree of identification.