Electrostatic potential and a simple extended electric dipole model of hydrogen fluoride as probes of non-bonding electron pairs in the cyclic ethers 2,5- dihydrofuran, oxetane and oxirane

摘要

The electrostatic potential near to the oxygen atom in each of the cyclic ethers 2,5-uddihydrofuran, oxetane and oxirane has been calculated by using a distributed multipole analysisud(DMA) of each molecule. The electrostatic potential energy V() of a unit non-perturbingudpositive charge was calculated (via the DMA of the cyclic ether molecule) as a function of theudangle  between the C2 axis of the cyclic ether and a vector of length r from the O atom to theudunit charge. The resulting potential energy functions each has two equivalent minima. Theudangles min at the minima are compared with the angles 0 and e made by the O⋯H bond withudthe C2 axes in the cyclic ether⋯HF complexes, as determined by rotational spectroscopy andudab initio calculations at the CCSD(T)-F12c/cc-pVTZ-F12 level of theory, respectively. Anudelectrostatic model of cyclic ether⋯HF complexes in which the DMA of the cyclic etherudinteracts with a simple extended electric dipole representation of HF is also used to calculateudthe variation of the potential energy VHF() of the HF molecule with . The angles minudgenerated by this model are also compared with 0 and e. The extent to which the electrostaticudpotential and the extended electric dipole HF model can be used as probes for the directions ofudnon-bonding electron pairs carried by O in these cyclic ethers is discussed.