Enthalpies of Formation of Hydrazine and Its Derivatives.

Enthalpies of formation, ΔH, in both the gas and condensed phase, and enthalpies of sublimation or vaporization have been estimated for hydrazine, NHNH, and its 36 various derivatives using quantum chemical calculations. The composite G4 method has been used along with isodesmic reaction schemes to derive a set of self-consistent high-accuracy gas-phase enthalpies of formation. To estimate the enthalpies of sublimation and vaporization with reasonable accuracy (5-20 kJ/mol), the method of molecular electrostatic potential (MEP) has been used.

Aggregation behavior of novel heptamethine cyanine dyes upon their binding to native and fibrillar lysozyme.

Two newly synthesized symmetrical heptamethine cyanine dyes, AK7-5 and AK7-6, absorbing in the region of low autofluorescence of biological samples, have been tested for their ability to detect proteins aggregated into amyloid fibrils. In aqueous solution these probes possess three absorption bands corresponding to the monomer, dimer and H-aggregate species. The association of the dye with fibrillar lysozyme was followed by the enhancement of the monomer band and the reduction of the H-band.

Novel benzanthrone probes for membrane and protein studies.

The applicability of a series of novel benzanthrone dyes to monitoring the changes in physicochemical properties of lipid bilayer and to differentiating between the native and aggregated protein states has been evaluated. Based on the quantitative parameters of the dye-membrane and dye-protein binding derived from the fluorimetric titration data, the most prospective membrane probes and amyloid tracers have been selected from the group of examined compounds. Analysis of the red edge excitation shifts of the membrane- and amyloid-bound dyes provided information on the properties of benzanthrone binding sites within the lipid and protein matrixes.

Enthalpy of Formation and O-H Bond Dissociation Enthalpy of Phenol: Inconsistency between Theory and Experiment.

Gas-phase O–H homolytic bond dissociation enthalpy in phenol, DH298°(C6H5O–H), is still disputed, despite a large number of experimental and computational studies. In estimating this value, the experimental enthalpy of formation of phenol, ΔfH298°(C6H5OH, g) = −96.4 ± 0.

Symmetric Meso-Chloro-Substituted Pentamethine Cyanine Dyes Containing Benzothiazolyl/Benzoselenazolyl Chromophores Novel Synthetic Approach and Studies on Photophysical Properties upon Interaction with bio-Objects.

A series of symmetric pentamethine cyanine dyes derived from various N-substituted benzothiazolium/benzoselenazolium salts, and a conjugated bis-aniline derivative containing a chlorine atom at meso-position with respect to the polymethine chain, were synthesized using a novel improved synthetic approach under mild conditions at room temperature. The reaction procedure was held by grinding the starting compounds for relative short times. The novel method is reliable and highly reproducible.