Molecular structure and conformation of 2,2 dichlorocyclopropylbenzene as determined by ab initio calculations and gas-phase electron diffraction

Abstract

The molecular structure of 2,2 dichlorocyclopropylbenzene has been investigated by theoretical calculations and gas-phase electron diffraction. Theoretical calculations at the HF, B3LYP and MP2 levels using 6-31G(d) and 6-311G(d,p) basis sets showed that the minimum energy conformer was rotated 20.0–30.0° (away from the chlorine atoms) from the perpendicular form ( τC 6C 1C 7H=90.0°). This result is consistent with the results from gas-phase electron diffraction where a value of 110.5(33)° was obtained for τC 6C 1C 7H. The major geometrical parameter values ( r g and ∠ α) obtained from least squares analysis are: r(C–H) av=1.080(10) Å, r(C–C) Ph=1.393(2) Å, r(C–C) cpr=1.507(6) Å, r(C 1–C 7)=1.488(6) Å, r(C–Cl) av=1.749(4) Å, ∠C 1C 7C 9=123.3°(22), ∠ClC 9C av 7=120.3°(4), ∠(HCC) cpr=118.4°(fixed), ∠(HCC) Ph=120.0°(fixed), τC 6C 1C 7H=111°(4).