Abstract
Here we report two new multicomponent
supramolecular rotors (1 and 2) based on 2,7-diphenyl-9H-carbazole
stators and two rotators brought together by a non-innocent C-H…O
interaction. This hydrogen bond serves a dual function: it constitutes the
rotational axis for THF and acts as a ‘brake’ for the motion of DABCO. Dynamic
characterization of 1 by VT 2H NMR experiments supports that
DABCO rotates about its supramolecular axis with jumps of 120º (3-fold) and a krot
>10 MHz at 300 K, but interestingly, this motion is reduced to 5 MHz
at 150 K. Concurrently, the THF experiences an atypical motion on an axis that
is perpendicular to that of DABCO, experiencing 180º jumps in the fast regime
even at 175 K. 1H(T1) relaxometry studies show that DABCO
has an Ea=3.5 kcal/mol, while for THF, an Ea=2.3 kcal/mol was computed
by periodic DFT. Fast and organized mobility of two constituents within
crystals is extremely infrequent and could have strong implications for future
applications of multicomponent solids with regulated dynamics.
Supplementary materials
Title
SI
Description
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