Colossal Linear NTE and PTE in Two-Fold Interpenetrated Network of a MOF Induced by Hinge-like Motion

Thermal expansion of a 2-fold interpenetrated MOF has been studied by variable temperature single crystal X-ray diffraction within a broad range of temperature. The change of unit cell parameters with increasing temperature shows colossal linear PTE and NTE exhibited by the MOF. The anomalous thermal expansion in MOF has been explained by hinge-like motion of the 2D rectangular grids in the crystal structure of the MOF with the change of temperature. Generally, large NTE is not anticipated in interpenetrated MOF due to strong repulsion between the atoms in close proximity that may prevent transverse vibration. Thermal expansion property of the MOF in this study is reversible in nature within the temperature between 100 and 450 K.