Slider-crank mechanism in a molecular crystal: conversion of linear thermal expansion of a lattice to circular rotation of a coordination chain

Abstract

Thermally induced circular rotation of anionic [Co(OCN)3(dabco)]∞ chains was observed in the quaternary molecular crystal of Co(dabco)K(OCN)3. The orientational angle of the ligand molecules was a function of temperature. This...

A Steric-Repulsion-Driven Clutch Stack of Triaryltriazines: Correlated Molecular Rotations and a Thermoresponsive Gearshift in the Crystalline Solid

“…However, certain intermolecular arrangements of the rotors in a crystal can allow correlated motion between multiple neighboring rotators, which effectively creates a molecular gear (Figure c). Recently, the design of crystals formed of molecules that demonstrate correlated mechanical motion has attracted significant interest in the field of crystalline molecular machines. − In particular, gear-like molecular rotation via multiple neighboring rotary moieties has been noted as an attractive target given the ability to transmit mechanical force at the molecular level and because the alternation of molecular geometry can be related to the physical properties of solids. − Correlated motion implies a reduction in entropy due to a decrease in the number of allowed geometries during the dynamic processes, resulting in a negative value in the entropy change (Δ S ‡ ) for the rotational frequency (Figure c) …”