On the structure of the H2CO-HNO dimer: Planar or orthogonal?

Publication date: Available online 1 March 2017 Source:Computational and Theoretical Chemistry Author(s): Alfred Karpfen The potential energy surface of the dimer formed between formaldehyde and nitrosyl hydride has been investigated theoretically at the MP2 and CCSD(T) levels using several extended basis sets. Six low-lying minima, all with Cs symmetry, were detected. Two of them are planar, four are non-planar. All dimers display geometry changes and vibrational frequency shifts characteristic for a formyl group engaged in hydrogen bonding: red shifts of C=O stretches and blue shifts of C-H stretches. In five of the dimers the N-H stretching frequency is also blue-shifted, but in one structure the blue shift vanishes, when applying harmonic vibrational analysis. Including anharmonic effects, all N-H stretches are blue shifted. The two most stable structures are nearly equienergetic and are reminiscent of the minima encountered in the formaldehyde dimer. Graphical abstract

Source: Computational and Theoretical Chemistry - March 1, 2017 Category: Chemistry Source Type: research