Institution: | aKey Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China bSciences College, Civil Aviation University of China, Tianjin, 300300, China cChemistry Department of Binzhou University, Binzhou 256600, China dChemistry Department and Institute of Material Science Xinzhou Teacher's University, Xinzhou, 034000, China |
Abstract: | Geometries and binding energies are predicted at B3LYP/6-311+G* level for the adenine–BX3 (X=F,Cl) systems and four conformers with no imaginary frequencies have been obtained for both adenine–BF3 and adenine–BCl3, respectively, and single energy calculations using much larger basis sets (6-311+G(2df,p)) and aug-cc-pVDZ were carried out as well. The most stable conformer is BF3 or BCl3 connected to N3 of adenine and with the stabilization energy of 22.55 or 20.59 kcal/mol at B3LYP/6-311+G* level (BSSE corrected). The analyses for the combining interaction between BX3 and adenine with natural bond orbital method (NBO) and the atom-in-molecules theory (AIM) have been performed. The results indicate that all the conformers were formed with σ–p type interactions between adenine and BX3, in which pyridine-type nitrogen or nitrogen atom of amino group offers its lone pair electron to the empty p orbital of boron atom and the concomitances of charge transference from adenine to BX3 were occurred. Frequency analysis suggested that the stretching vibration of BX3 underwent a red shift in complexes. Adenine–BF3 complex was more stable than adenine–BCl3 although the distance of B–N is shorter in the later. |