Control of Molecular Rotor Rotational Frequencies in Porous Coordination Polymers Using a Solid-Solution Approach

Rational
design to control the dynamics of molecular rotors in
crystalline solids is of interest because it offers advanced materials
with precisely tuned functionality. Herein, we describe the control
of the rotational frequency of rotors in flexible porous coordination
polymers (PCPs) using a solid-solution approach. Solid-solutions of
the flexible PCPs [{Zn­(5-nitroisophthalate)x(5-methoxyisophthalate)1–x(deuterated 4,4′-bipyridyl)}­(DMF·MeOH)]n allow continuous modulation of cell volume by changing the
solid-solution ratio x. Variation of the isostructures
provides continuous changes in the local environment around the molecular
rotors (pyridyl rings of the 4,4′-bipyridyl group), leading
to the control of the rotational frequency without the need to vary
the temperature.