Density Functional Theory Investigation of the Binding of ThioTEPA to Purine Bases: Thermodynamics and Bond Evolution Theory Analysis.

Density functional theory with the ωB97X-D exchange-correlation functional together with implicit as well as explicit solvation is used to describe the reactions of the adenine and guanine purine bases on ,',″-triethylenethiophosphoramide (thioTEPA), an alkylating agent used as an anticancer drug. This reaction is decomposed into (i) a nucleophilic addition and (ii) a proton "migration" that is mediated by the solvent molecules. The calculations reveal that the first step is rate determining and that the presence of an explicit water molecule to mediate the proton migration has a negligible role on the kinetics of the first step, so that the focus is set on the first step of the reaction.

Magnetically-induced current density investigation in carbohelicenes and azahelicenes.

A computational study of the magnetically-induced current (MIC) density has been carried out for a variety of ortho fused polycyclic aromatic molecules at the density functional theory level with the gauge including magnetically induced current (GIMIC) method. With this method, the aromatic character of each ring in a homologous series of carbohelicenes with an increasing number of fused benzene rings is assessed and compared with other aromaticity criteria such as the Nucleus Independent Chemical Shift [NICS(0), NICSzz(0)] and Bond Length Alternation (BLA) parameters. All criteria indicate that the two outer rings are the most aromatic ones [i.

Theoretical investigation of the regioselective ring opening of 2-methylaziridine. Lewis acid effect.

The formation of substituted 1,2-diamines via the regiospecific nucleophilic ring opening of 2-methylaziridine with methylamine was performed by nucleophilic attack at aziridine carbon atoms. A detailed theoretical study was investigated by density functional theory (DFT) at the B3LYP level and second order Moller Plesset perturbation theory (MP2) by using the 6-311G(d,p) basis set. The third Grimme correction term (D3) was used to take into account weak interactions.