| Resumo: |
Gas phase standard state (298.15 K, 1 atm) geometries of the perchlorinated and perbrominated C~3~ through C~6~ n-alkanes were calculated using the B3LYP, B97D, M062X, and PBE0 density functionals with the 6-311++G(d,p) basis set. For both halogen classes and at all levels of theory, the C~3~ compounds adopt a trans conformation analogous to that of perfluoropropane. Similar to their perfluorinated counterparts, the perchlorinated and perbrominated C~4~ through C~6~ n-alkanes are predicted to have helical geometries. In contrast to perfluoroalkyl chains, the central CCCC dihedral angles of the perchlorinated and perbrominated derivatives are expected to decline with increasing chain length.
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