Base properties of H2CO in the excited 3n→π* state

✍ Scribed by Janet E. Del Bene; John D. Watts

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 146 KB
• Volume: 77
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/(sici)1097-461x(2000)77:1<187::aid-qua17>3.0.co;2-3

✦ Synopsis

Calculations using the coupled-cluster method with singles and doubles Ž . based on a restricted open Hartree-Fock reference ROHF-CCSD with the augЈ-cc-pVDZ basis set have been carried out to investigate the structures, energies, and vibrational spectra of protonated H CO and of the hydrogen-bonded complexes of H CO with HF in 2 2

the excited 3 n ª * state. Two protonated isomers, H CO q and H COH q , exist in the 3 2

3 n ª * state and are separated by an appreciable barrier. The carbon-protonated q Ž 298 . species H CO has a computed proton affinity ⌬ H of 161.7 kcalrmol and is 12.9 3 kcalrmol more stable than the O-protonated isomer. Two complexes of H CO with HF 2 Ž 0 . exist on the triplet potential surface, with binding enthalpies ⌬ H of y2.8 and y2.3 kcalrmol for the complexes hydrogen-bonded at O and C, respectively. The barrier to HF transfer from C to O is less than 1 kcalrmol.