Sunghwan Kim - Conformational stabilization of phthalan: Physical origin of tiny ring-puckering barrier

Version 5

      Publication Details (including relevant citation   information):

      S. Jeon, J. Choo, S.   Kim, Y. Kwon, J.-Y. Kim, Y.-I. Lee, H. Chung;

      Journal of Molecular Structure, 2002,   159, 609.



      The conformational property of phthalan has been investigated   using ab initio calculation and natural bond orbital (NBO)   analysis methods. Geometry optimizations for the planar   (C2v) and puckered (Cs) conformers have   been carried out using the HF, B3LYP, and MP methods, and the   results indicate that this molecule has a tiny ring-puckering   barrier. This barrier appears to be in good agreement with the   previous experimental result. NBO analysis shows that the tiny   ring-puckering barrier is closely related to the molecular   orbital interactions around the C-O bonds of the five-membered   ring. The gas-phase infrared and liquid-phase Raman spectra of   phthalan and 1,3-benzodioxole have been recorded and analyzed in   terms of C2v symmetry. Vibrational frequency   calculations using the B3LYP method have also been performed to   compare with the spectroscopic data. The B3LYP frequency   calculations do a reasonable job of estimating the frequencies.


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