posted on 2016-01-26, 00:00authored byJędrzej Marciniak, Julia Bąkowicz, Michał A. Dobrowolski, Kamil F. Dziubek, Michał Kaźmierczak, Damian Paliwoda, Kacper
W. Rajewski, Szymon Sobczak, Marcin Stachowicz, Andrzej Katrusiak
Undisturbed
by stronger interactions, CH···π
hydrogen bonded motifs have been determined in four polymorphs of
toluene. Two new toluene phases, monoclinic phase III of space group
symmetry P21 crystallized between 1.1
and 1.5 GPa and orthorhombic phase IV of space group Pbca obtained between 1.27 and 2.1 GPa, reveal 3-dimensional CH···π
aggregation competing with CH···HC interactions of
molecules, while the 2-dimensional aggregation is characteristic of
low-temperature toluene phases I and II. The most frequent CH···π
bonding motif involves the methyl H-donor and the acceptor atoms β
and γ. The motifs of H-bonds and their frequency depend on the
stability regions of toluene phases outlined in the pressure–temperature
phase diagram.