Deformable Mn(iii)-Schiff-base dimer for anomalously large positive and negative anisotropic thermal expansionsElectronic supplementary information (ESI) available: Experimental details, crystal data and additional figures. CCDC 1530888-1530892. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7ce00292k

A new molecular crystal with supramolecular layers assembled by a Mn( iii )-Schiff-base dimer and fumaric acid was investigated by means of variable-temperature single-crystal structural analyses. The Mn( iii )-Schiff-base dimer reveals remarkable thermally-induced deformation and hence causes anomalously large positive and negative anisotropic thermal expansions in the supramolecular layers, providing a new type of promising weak supramolecular synthon for designing sensitive thermomechanical actuators. A new molecular crystal consisting of supramolecular layers assembled by a Mn( iii )-Schiff-base dimer and fumaric acid reveals anomalously large positive and negative anisotropic thermal expansions in the layers.