Intermolecular interactions in the crystalline structure of some polyhalogenated Di- And triamino Pyridines: Spectroscopical perspectives.

Supramolecular synthon is identified as a unit and provides important structural and energetic information in the study of organic crystals. However, the direct estimation of the supramolecular interaction remains challenging. In the present work six polyhalogenated di- or triamino pyridines were synthesised, their crystalline structure was characterised, and corresponding supramolecular synthons were studied using a combination of quantum mechanical calculations and FT-IR and Raman spectroscopy.

How do electron donating substituents affect the electronic structure, molecular topology, vibrational properties and intra- and intermolecular interactions of polyhalogenated pyridines?

Seven polyhalogenated pyridine derivatives bearing an amino or a hydroxyl group, either at the or position, were studied using a combined experimental and computational approach. The presence of an electron donating substituent strongly impacted on the geometry, electronic structure, electrostatic properties, molecular topology and vibrational characteristics of these compounds compared to the corresponding polyhalogenated pyridines. In particular the attention was focused on changes in wavenumbers, force constants and intensity of the seven in-plane Ring Normal Modes (RNMs).

Impact of fluorination and chlorination on the electronic structure, topology and in-plane ring normal modes of pyridines.

Seven partially and fully fluorinated/chlorinated pyridines were investigated by means of FT-IR and Raman spectroscopy combined with quantum chemical calculations, mainly aiming to detect how the nature and position of F and Cl substituents affect the in-plane ring normal modes (RNMs) of pyridines in terms of vibrational wavenumbers, force constants, IR intensities and Raman activities. Taking pyridine as the reference, the RNMs and some derived RNMs through coupling with related C-X (X = F, Cl) stretching vibrations were identified on the basis of their composition in terms of internal coordinates. The impact of fluorination and chlorination on these RNMs was also discussed from the perspective of frontier molecular orbitals (MOs), maps of the molecular electrostatic potential (MEP) and the molecular topology.

[The genetic and biochemical mechanisms of the development of diabetic nephropathy in children].

The mechanisms responsible for the development of microangiopathies in type diabetes mellitus (DM1) are complex and under extensive study. Fresh data on the pathogenesis of DM1 make it possible to direct actual ways to the studies aimed at preventing the complications of this disease. The purpose of this study was to examine the contribution of the polymorphic types of the VNTR polymorphism of endothelial NO-synthase gene (NOS3) and the I/D polymorphism of angiotensin-converting enzyme (ACE), the status of the proteolytic systems and lipid metabolic disturbances to the development of diabetic neuropathy (DN).