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The electronic structure and related electronic properties of two novel isostructural octacyanometallates Cd2(H2O)4[MoIV(CN)8]·2H2O and Cd2(H2O)4[WIV(CN)8]·2H2O are described from a combined experimental and computational approach. The impact that the octacoordinated heavy metals W and Mo have on the electronic structure and optical response of isostructural materials whose electronic properties strongly depend on the crystal structure is discussed. It is found that the effect of the polarization power of the metal centers, combined with the ligand field of cyanos, produces considerable changes in the electronic structure and, consequently, in the band gap energy. The ab initio calculations, which were performed with generalized gradient PBE and hybrid HSE06 density functionals, accurately reproduce the electronic structure of [Mo(CN)8]4- and [W(CN)8]4- building units, revealing that the electronic transitions associated with the band gap energy have an origin in the charge transfer phenomena of metal to ligand nature. Moreover, the optical band gap transitions have an allowed indirect behavior in the Γ â†’ M → D direction which is associated with the (x2 - y2) → π* transition. The allowed direct and indirect (experimental and theoretical) band gap energies together with the exciton effective masses are reported.

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The electronic structure and derived optical properties of five synthesized metal-dicyanoaurate(I), (K)M[Au(CN)2], (M = Mn, Co, Ni, Zn and Cd), coordination polymers are described from a combined experimental analysis and theoretical study based on density functional theory. In this sense, the topological features that influence the electronic structure, which in turn give rise to electronic transitions associated with the band gap energy, are studied from first principles calculations (with hybrid HSE06 and GGA-PBE density functionals) and electronic spectroscopy. The impact of gold (through spin-orbit coupling) and aurophilic interactions on the electronic transitions that gives rise to optical properties is described. The calculated projected density of states and band dispersion diagrams shed light on the molecular orbital distribution and the role of a dicyanoaurate(I) molecular block as the origin of the optical properties. Infrared, Raman and ultraviolet-visible spectroscopic analyses reveal the effect that charge transfer interactions, of a metal → ligand and metal → metal nature, have on the electronic behavior within the solids through association with the polarizing power of transition metals and gold atoms.

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A combined study of vibrational and thermodynamic properties of metaboric acid (BOH)3O3 crystal polymorphs α, ß, and γ were obtained through density functional theory (DFT) calculations in an attempt to resolve the conflicting assignments that currently exist in the literature for them. A complete correlation between the normal-mode assignment and vibrational signatures to distinguish particular features of each metaboric acid polymorph, in particular, those related to motions of the planar layers in α-(BOH)3O3, with a level of detail surpassing essays based on previous published experimental works has been achieved. Besides, no DFT-based research work was published early on the (BOH)3O3 polymorph vibrational properties, and our DFT-simulated infrared and Raman spectra for all metaboric acid polymorphs agree very well with experiment. Comparison of the previously published experimental IR and Raman spectroscopic results with predictions from higher levels DFT calculations allows identification of the in-plane and out-of-plane B-O bending modes. For example, the strongest measured (DFT-calculated) Raman modes of α-(BOH)3O3 at 591 and 797 cm-1 (599 and 810 cm-1) are identified as vibrational signatures of breathing B3O3/Ag in-plane modes, while the shoulder in the lattice modes region at 135 (143) cm-1 is the vibrational signature of the bending B3O3/B1g out-of-plane mode. Phonon-dispersion bands and their respective phonon densities of states were also evaluated for each system, as well as temperature-dependent curves for entropy, enthalpy, free energy, heat capacity, and Debye temperature. Phonon dispersion curves are singular for each (BOH)3O3 species, and a consistent gap decrease between the lowest and highest frequency vibrational bands was observed. The DFT-based calculations also revealed that the noncovalent interactions prevalent in the α and ß crystals lead to significant differences with respect to the thermodynamic properties in comparison with the γ phase.

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The photo-induced charge transfer in four series of Prussian blue (PB) analogues was studied from photoacoustic spectra. In cobalticyanides the observed signals were assigned to a metal-to-ligand charge transfer, which appears as a shoulder below 450 nm, and to d-d transitions for Co(II), Ni(II) and Cu(II) complex salts. No evidence of metal-to-metal charge transfer was observed for this series, which is probably due to the high stability of low spin cobalt(III) in the hexacyanide complex. Photoacoustic spectra for ferricyanides are broad bands, which result particularly intense up to 750 nm. Such features were attributed to the overlapping of contributions from metal-to-ligand (<600 nm) and metal-to-metal charge transfer transitions, with probably also a minor contribution from d-d transitions in the outer metal. The spectra for the ferrocyanides series are dominated by the metal-to-ligand charge transfer band below 550 nm, approximately 100 nm above this transition in cobalticyanides. Within the studied solids, the most intense and broad metal-to-metal charge transfer bands were found for a series of low spin Co(III) high spin Co(II) hexacyanoferrates(II,III) and with similar features also for ferric ferrocyanide (Prussian blue), assigned to Fe(II)-->Co(III) and Fe(II)-->Fe(III) photo-induced transition, respectively. The first of these transitions requires of more energetic photons to be observed, its maximum falls at 580 nm while for Prussian blue it is found at 670 nm. Prussian blue analogues are usually obtained as nanometric size particles and many of them have a microporous structure. The role of surface atoms on the observed charge transfer bands in the studied series of compounds is also discussed.

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El dolor ha sido considerado un aspecto dentro de los sìntomas más comunes dentro de las laceraciones de la mucosa oral. El tratamiento aplicado en estos va dirigido fundamentalmente a la dismunución de esta sintomatología. Numerosos han sido los métodos para lograr este propósito, que van desde los ácidos que cauterizan la lesión, hasta sustancias protectoras y cicatrizantes. El trabajo tiene como objetivo mostrar los resultados clínicos de la aplicación de un cianocrilato de n-butilo (Tisuacryl)en la disminución de las molestias dolorosas en lesiones de la mucosa oral producidas por diferentes causas. El producto se ha evaluado en esta aplicación desde 1998 en 25 pacientes, sin restringir edad o sexo que acudieron a los servicios estomatológicos de la Empresa Aerogaviota y la clìnica estomatológica Docente de Bauta con lesiones o laceraciones de la mucosa oral de cualquier localización, dimensión y etiología. Los resultados demuestran que el tratamiento con Tisuacryl disminuye el dolor en los casos de lesiones de mucosa oral, permitiendo al paciente la ingestión inmediata de alimentos(AU)

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The action of ketamine (50 microM) and 4-aminopyridine (4-AP) (50 microM) on the frog (Hyla crepitans) neuromuscular junction using standard intracellular recording techniques was investigated. In our experiments the amplitude of evoked end plate potential was decreased by ketamine and increased by 4-AP, which is similar to the effects reported by other investigators. However, novel effects of the drugs on postsynaptic acetylcholine receptors were detected when miniature end plate potential (MEPP) amplitude and time-course were analyzed. The experiments were performed and registered in presence of 1% dimethylsulfoxide to augment frequency of MEPP's. When ketamine was added to the saline solution, MEPP amplitude control values were reduced from 226 (214, 240) microV (n = 529, median and its 95% confidence interval) to 140 (130, 151) microV (n = 143) by 50 microM ketamine. 4-AP alone also depressed MEPP amplitude to 129 (70, 152) microV (n = 91). The two drugs are partial antagonists, when they were applied together, MEPP amplitude was 180 (172, 188) microV (n = 207). The effect of ketamine on time course of MEPP's, expressed as time to peak, reduced the control values of 4.74 (4.61, 4.88) msec (n = 529) to 3.84 (3.72, 4.01) msec (n = 143) (P less than 0.001); the effect of 4-AP was to reduce the control values to 1.93 (1.79, 2.10) msec (n = 91). The time to peak after adding ketamine and 4-AP was 3.25 (3.12, 3.38) msec (n = 207), expressing an antagonistic effect of the drugs. All values are statistically distinct (P less than 0.001). Thus, our results show that a postsynaptic mechanism is responsible for a significant part of the antagonism of ketamine effects by 4-AP.

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