dft study and nbo analysis on conformers of 1,3,2-dithiaphosphane -2-sulfide derivatives

Stereoelectronic interactions associated with generalized anomeric effect (gae) and electrostaticeffect on the conformational behaviors of 2,5,5-trimethyl-1,3,2-dioxaphosphinane 2-sulfide (1), -dithiaphosphinane 2- sulfide (2) and -diselenaphosphinane 2- sulfide (3) were investigated usingdft (density functional theory) method. these compounds have been analyzed by means ofdft method and natural bond orbital (nbo) interpretation. these compounds were fullyoptimized with dft: b3lyp method using 6-311+g∗∗ and 6-31g∗∗ basis sets. both basis setsshowed that the gibbs free energy difference values (δgeq-ax) between the axial and equatorialconformers decreases from compounds 1 to 3. based on results obtained from the nbo analysis,stereoelectronic effect corresponding to the naxx→σ*p-c electron delocalization in the equatorialconformations and naxx→σ*p-s in the axial conformations have the highest level of stabilityenergy, where x= [o, s, se]. stereoelectronic effect through the naxx→σ*p-s interaction is ofmajor relation or impressive to demonstrate conformational preference in the specificx─p(s)me─x segment. our results show that the gae is more considerable for the justificationof the conformational preferences of compounds than the other factors [1-2].