X-ray study of the molecular structure and of the internal ordering degree in 1,3,5-tri-tert-butylbenzene at 363Â K

The paper presents the structure and molecular correlations in liquid 1,3,5-tri-tert-butylbenzene C6H3[C(CH3)3]3 determined for the first time by the X-ray diffraction method. Experimental function i(S) was determined by X-ray scattering from a liquid sample and compared with the theoretical function im(S) calculated for the most probable assumed model of the 1,3,5-tri-tert-butylbenzene structure. The most probable parameters of molecule 1,3,5-tri-tert-butylbenzene were determined from the detailed analysis of the differential radial distribution function of electron density. Theoretically calculated parameters were compared with experimentally measured data. Good agreement between the theoretical and experimental curves is obtained on assuming the statistically most probable model of this molecule. The mean bond length between a C atom in an aromatic ring and the central C atom of a tert-butyl group, the bond C(1)−C(7) is 1.54 Å. Local, most probable manners of packing and mutual orientation of molecules within the space of the first coordination sphere are discussed. The local structure of the liquid 1,3,5-tri-tert-butylbenzene is similar to the crystalline structure of the compound.