Conformations of diethyl ether and its interaction with pyrrole at low temperatures

Conformations of diethyl ether (DEE) were studied at low temperatures in N-2 and Ar matrixes. Computations performed at B3LYP/aug-cc-pVDZ level of theory yielded three minima corresponding to tt, tg(+/-) and g(+/-) g(+/-) conformers of DEE. Of the three, the tt and tg(+/-) conformers of DEE were experimentally identified in N-2 and Ar matrixes. Furthermore, hydrogen bonded complexes of pyrrole (py) with DEE have been investigated using Density Functional Theory (DFT) and matrix isolation infrared spectroscopy. Computations performed at B3LYP level of theory using aug-cc-pVDZ basis set on pyrrole with tt and tg(+/-) conformers of DEE gave py-DEE-tt and py-DEE-tg(+/-) complexes, both characterized by N-H center dot center dot center dot O interaction. Experimental evidence for the formation of pyDEE-tt and py-DEE-tg(+/-) complexes was affirmed from the shifts in the N-H stretching, N-H bending regions of pyrrole and C-O-C and C-H stretching regions of DEE. NBO analysis was carried out to understand the charge-transfer delocalization interactions in the conformers of DEE and its hydrogen bonded complexes. (C) 2019 Elsevier B.V. All rights reserved.