Generalized Valence Bond Description of Chalcogen–Nitrogen Compounds. II. NO, F(NO), and H(NO)

2015-03-05T00:00:00Z (GMT) by Tyler Y. Takeshita Thom H. Dunning
The electronic structure of the ground state of NO and those of F­(NO) and H­(NO), that is, the XNO and NOX isomers with X = F, H, were analyzed within the framework of generalized valence bond theory. In distinct contrast to the ground state of NS, it was found that the two-center, three-electron π interaction in NO­(X<sup>2</sup>Π) is composed of a lone pair on O and a singly occupied orbital on N. Thus, F and H addition to NO preferentially leads to FNO and HNO. Somewhat surprisingly, the NOF and NOH isomers were found to be weakly bound, although for different reasons. The NOF state has a very unusual through-pair interaction with a NO–F bond length 0.444 Å longer than its covalent counterpart in OF­(X<sup>2</sup>Π), while NOH arises from the N­(<sup>2</sup>D) + OH­(X<sup>2</sup>Π) separated atom limit, similar to what we found for NSH.