Theoretical approach to the molecular conformation of nonfused biheterocycles. Bifurans and furylpyrroles
The internal torsional potential for the three structural isomers of bifuran (2,2'-, 2,3'-, and 3,3'-) and the four furylpyrroles (2,2'-, 2,3'-, 3,2'-, and 3,3'-) have been derived from standards SCF STO-3G and 4-31G calculations. Important differences in the potential shapes arise from the two basis sets mainly concerning the planar or out-of-planar structure of equilibrium conformations and the torsional barrier heights. The more relevant results are as follows: (i) 2,2'-isomers show twofold potentials and planar equilibrium conformations. The significance of the greater stability of the cis conformer of 2,2'-furylpyrrole is discussed. (ii) For the rest of the isomers, STO-3G predicts twofold potentials in all cases, whereas 4-31G potentials are found to be greatly dependent on the structure of the interannular region. In particular, fourfold potentials implying gauche out-of-plane equilibrium conformations and strong decreasing barrier heights are found whenever four hydrogen atoms are present in that region.
- Research Organization:
- Universidad de Valencia, Spain
- OSTI ID:
- 6970437
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 91:3; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360603 -- Materials-- Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AZOLES
DATA
DIMERS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ENERGY
ENERGY LEVELS
EXCITED STATES
FURANS
HETEROCYCLIC COMPOUNDS
INFORMATION
ISOMERS
MATHEMATICAL MODELS
MOLECULAR MODELS
MOLECULAR STRUCTURE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POTENTIAL ENERGY
PYRROLES
SELF-CONSISTENT FIELD
STABILITY
THEORETICAL DATA
VIBRATIONAL STATES