Optical Application of (Pigmented) Sol-Gel Coatings

The performance of the anti-reflection stack antimony-doped tin oxide/SiO₂ improves considerably if the refractive index of the SiO₂ layer decreases from 1.45 to 1.41 by the introduction of porosity. Porosity can be introduced by the addition of high-boiling co-solvents (or templates e.g. sebacates) to the coating liquid. Fine-tuning of the liquid composition allows the formation of a homogeneous, non-scattering SiO₂ layer with a refractive index of 1.41 and pencil hardness of H7-H8 on large screens (diagonal >1 meter) if a curing temperature of 160°C was used.Another interesting application is the formation of transparent, strongly coloured layers on lamp bulbs. Due to the high operating temperatures, strict requirements are placed on the matrix material and the pigment used. Inorganic pigments have good temperature stability, but their colour saturation is weaker than that of organic pigments, demanding the formation of relatively thick coatings. In order to achieve this, Methyltrimethoxysilane (MTMS) was used as matrix material precursor. Fully transparent, temperature-resistant coatings were developed.     

Structural study of highly halogenated dihydropyridine derivatives as potential calcium channel modulators

Two dihydropyridines endowed with fluorine atoms ( 3 ) and fluorine and chlorine atoms ( 4 ) have been synthesized and structurally characterized by experimental X‐ray analyses and theoretical calculations at the semiempirical (AMI) and ab initio (HF/6–31G*) levels. The results show that these compounds meet the required criteria to act as potential calcium channel modulators.     

The importance of the external potential on group electronegativity

The electronegativity of groups placed in a molecular environment is obtained using CCSD calculations of the electron affinity and ionization energy. A point charge model is used as an approximation of the molecular environment. The electronegativity values obtained in the presence of a point charge model are compared to the isolated group property to estimate the importance of the external potential on the group's electronegativity. The validity of the "group in molecule" electronegativities is verified by comparing EEM (electronegativity equalization method) charge transfer values to the explicitly calculated natural population analysis (NPA) ones, as well as by comparing the variation in electronegativity between the isolated functional group and the functional group in the presence of a modeled environment with the variation based on a perturbation expansion of the chemical potential.