The conformational stability of newly synthesised bicyclo[3.3.1]nonane-2,6-dione C9H12O2 (D26) and bicyclo[3.3.1]nonane-2,9-dione C9H12O2 (D29) was studied. Ab initio calculations (HF level using 6-31G** basis set) reveal that due to six-membered ring inversion four conformers exist in the case of D26, whereas five of them exist for D29. The double-chair (CC) conformer is the most stable for D26 and the chair-boat (CB) conformer is 3.4 kJ mol-1 higher in energy. On the contrary, the chair-boat (CBo) conformer of D29 is the most stable and the chair-chair conformer (CC) is 2.5 kJ mol-1 higher in energy. Raman and IR spectra of the title compounds were recorded in solid, liquid and gas phases for the first time. Assignment of vibrational spectral bands for both molecules was made by comparing theoretical and experimental spectra.
- Conformational stability
- Vibrational spectroscopy
ASJC Scopus subject areas
- Structural Biology
- Organic Chemistry
- Physical and Theoretical Chemistry
- Atomic and Molecular Physics, and Optics