جستجوی مقالات مرتبط با کلیدواژه « LogP » در نشریات گروه « شیمی »

Density functional theory (DFT) calculations were performed to investigate the features of vitamin B3 (Vit-B3) in oil and water environments. Two up and down structural conformations were found based on the orientation of hydrogen atom of attached carboxylic acid group to pyridine scaffold, in which the up-conformation was found more suitable than the down-conformation. The models were stabilized in gas phases and 1-octanol and water solvents environments to explore the partition coefficient (LogP) for each conformation. In addition, the electronic features were investigated based on frontier molecular orbital levels. The results of this work indicated a higher suitability of formation for the up-conformation in all three environments and the highest suitability of formation of both up and down conformations in water medium. Accordingly, the LogP value was found smaller than one indicating watery tendency for the models. As a final remark, the structural and electronic features of Vit-B3 indicated insights into its development for further applications.

The synthesis and characterization of 1, 3-bis [(furan-2-yl) methylene] urea (BFMU) and 1, 3-bis [furan-2-yl) methylene] thiourea (BFMT) have been reported by our research team. The effects of solvents polarity on their electronic transition energies (HOMO-LUMO) and associated qualitative structure activity relationship parameters (i.e. log P, ionization energies and global hardness) were investigated in this study. The lower HOMO-LUMO energy gap values of BFMT (3.42 - 3.76 eV) in the solvents of choice (water, ethanol, toluene and dimethylsulphoxide) is an indication of higher distribution of charges and probability of higher activities of BFMT relative to BFMU with energy gap in the range: 4.27 - 4.54 eV. From the frontier molecular orbital study of BFMU, the HOMO centers over the entire molecule.  However, the π- electrons of the LUMO are also over the entire molecule except one of the furan rings. Similar trends was observed for the HOMO of BFMT with electron delocalization excluding one of the furan ring, while the LUMO π- electrons system are more localized on the C=N, C=O and C-S bonds than the furan rings. These attest to the charge transfer (CT) characteristic properties of the compounds in the studied solvents. The logPoctanol/water values for the studied compounds which are less than 3, pointed to their usefulness in industrial development especially for agrochemical products.

It is well known that the chemical behavior of a compound is dependent upon the structure of itsmolecules. Quantitative structure – activity relationship (QSAR) studies and quantitative structure –property relationship (QSPR) studies are active areas of chemical research that focus on the nature ofthis dependency. Topological indices are the numerical value associated with chemical constitutionpurporting for correlation of chemical structure with various physical properties, chemical reactivityor biological activity. Graph theory is a delightful playground for the exploration of proof techniquesin Discrete Mathematics and its results have applications in many areas of sciences. One of the usefulindices for examination of structure- property relationship is Randic' index. In this study isrepresented the relationship between the Randic', Balaban and Szeged indices and Harary numbers tothe octanol-water partition coefficient (logP) of monocarboxylic acids (C2- C20) are established, andthen, some useful topological indices for examination of the structure- property relationship arepresented.