The molecular structure, conformations and vibrational spectra of 2,2-di(chloromethyl)-1,3-dichloropropane and 2,2-di(bromomethyl)-1,3-dibromopropane

Abstract

The IR and Raman spectra of 2,2-di(chloromethyl)-1,3-dichloropropane (C(CH 2Cl) 4) and 2,2-di(bromomethyl)-1,3-dibromopropane (C(CH 2BR) 4) were recorded as melts and as solutes in various solvents. Spectra of the solids were observed at various temperatures between the melting points and 90 K. High pressure IR spectra (0–20 kbar) of the compounds were recorded between 300 and 450 K. The crystal structures of both compounds were determined by X-ray crystallographic measurements of single crystal at ca. 130 K. In the crystalline state both compounds exist in the D 2d conformer, whereas in the melt and in solution an additional conformer probably of symmetry S 4 was assigned supported by force constant calculations. Unlike neopentane and various chlorinated neopentanes with one, two or three chlorine substituents, no plastic crystalline phase was detected for the title compounds. The structure of both molecules were disordered with two molecules in the monoclinic unit cell ( P2 1/ n).