Geometries and dissociation energies are predicated at MP2-/6-31+G^* and B3LYP/6-31+G^* levels respectively. Single point energy calculations using CCSD method at 6-31+G^* level are also carried out on the four obtained conformers to confirm the results. Then vibrational analysis are made using B3LYP/6-31+G^* method. Single point energy calculations at much larger basis sets and natural bond orbital analysis have been also carried out on th eoptimized conformers. The outcome indicates that the conformer with the boron atom directly connected to the nitrogen atom is the most stable one with a dissociation energy of 141.50 kJ/mol. The results for the conformer with the nitrogen atom close to one of the hydrogen atom in BH~3 differ from each other at MP2 and B3LYP levels. The stability of the other two conformers (with boron atom lying on one of the pyridine carbons) is between that of the aforementioned two conformers and their dissociation energies are 15.18 and 14.06 kJ/mol (MP2/6-31+G^*), respectively.

Key words: PYRIDINE, BORON COMPOUNDS, DISSOCIATION, INTERACTIONS, COMPLEX, MOLECULAR ORBITAL THEORY, CONFIGURATION, NSFC