The aim of this work is to convince practitioners of (31)P NMR methods to regard simple GIAO quantum chemical calculations as a safe tool in structural analysis of organophosphorus compounds. A comparative analysis of calculated GIAO versus experimental (31)P NMR chemical shifts (CSs) for a wide range of phosphorus containing model compounds was carried out. A variety of combinations (at the HF...

Electron densities at nuclei are difficult to calculate accurately with all-Gaussian basis sets because they lack an electron-nuclear cusp. The newly developed mixed ramp-Gaussian basis sets, such as R-31G, possess electron-nuclear cusps due to the presence of ramp functions in the basis. The R-31G basis set is a general-purpose mixed ramp-Gaussian basis set modeled on the 6-31G basis set. The ...

We examined complexes between cucurbit[6]uril and each of ortho-, meta-, and para-phenylenediamine using computational methods, Fourier transform ion cyclotron resonance mass spectrometry, and ion mobility spectrometry. These fundamental gas phase studies show that the lowest energy binding sites for ortho- and meta-phenylenediamine are on the exterior of cucurbit[6]uril, whereas para-phenylene...

Computational studies on three tautomeric forms of four 1,5,6,7-tetrahydro- 4H-indazol-4-one derivatives: 1,5,6,7-tetrahydro-4H-indazol-4-one (1), 6,6-dimethyl- 1,5,6,7-tetrahydro-4H-indazol-4-one (2), 3-methyl-1,5,6,7-tetrahydro-4H-indazol-4-one (3) and 3,6,6-trimethyl-1,5,6,7-tetrahydro-4H-indazol-4-one (4), have been performed at different levels, ranging from semiempirical AM1, ab initio Ha...

The anti-cancer Nano drugs Cisplatin, Carboplatin, Nedaplatin, Oxaliplatin, Heptaplatin and Lobaplatin were characterized by 1HNMR, 13CNMR, 31PNMR, Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR), FT-Raman, HR Mass and UV-Vis spectroscopies and also by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Differential Thermal Analysis-Thermal Gravim Anal...

5-Cyanoimino-4-oxomethylene-4,5-dihydroimidazoles (1) (R at N1) have been discussed as possible intermediates in nitrosative guanine deamination, which are formed by dediazoniation and deprotonation of guaninediazonium ion. The parent system 1 (R = H) and its N1 derivatives 2 (R = Me) and 3 (R = MOM) are considered here. Protonation of 1-3, respectively, may occur either at the cyano-N to form ...

The B3LYP density function was used with the 6-31G(d) basis set to perform relaxed energetic contour maps of the charged form of j-carrabiose in the gas phase and for the neutral form first in the gas phase and then by simulating the presence of water as solvent using the Onsager model. Only one starting conformation has been considered to perform all the calculations. Rigid energetic maps have...

A detailed investigation of the reaction path for the thermal w x rearrangement of 3,4-dihydro-1a H-azirine 2,3-c pyrrol-2-one to yield a cyanoketene]formaldimine complex is carried out at the MP2r6-31G* and B3LYPr6-31G* levels of theory. The ring opening of the five-membered pyrrolinone ring and the formation of the nitrile group takes place in a concerted manner, presenting a significant stra...

A series of 5-substituted 2,4-thiazolidinedione derivatives which exhibit different pharmacological properties such as anti-hyperglycemic, anticancer, antioxidant and anti-neurodegenerative has been quantum chemically investigated to clarify elucidated electronic geometrical features. B3LYP functional with three basis sets including 6-31G, 6-31G(d) 6-31G(d,p) was made use optimize the three-dim...