The Role of Hyperconjugation on the Structure and C-H Stretching Frequencies of 3,3-Ethane-1,2-diyl- bis-1,3,5-triazabicyclo[3.2.1]octane (ETABOC): An X-Ray Structure and Vibrational Study

Structural and vibrational studies have been carried out for the most stable conformer of 3,3-ethane-1,2-diyl-bis-1,3,5-triazabicyclo[3.2.1]octane (ETABOC) at the DFT/B3LYP/6-31G(dp) level using the Gaussian 03 software. In light of the computed vibrational parameters, the observed IR Bolhmann bands for the C-2V, C-2, and C-i symmetrical structures of ETABOC have been analyzed. Hyperconjugative interaction was done by Natural Bond Orbital Analysis. Interpretation of hyperconjugative interaction involving the lone pairs on the bridgehead nitrogen atoms with the neighboring C-N and C-C bonds defines the conformational preference of the title compound. The recorded X-ray diffraction bond parameters were compared with theoretical values calculated at B3LYP/6-31G(d,p) and HF/6-31G(d,p) level of theory showed that ETABOC adopts a chair conformation and possesses an inversion center.