Single-crystal to single-crystal transformation from a hydrophilic–hydrophobic metal–organic framework to a layered coordination polymer

Abstract A new metal–organic framework (MOF) [Cu 5 (pz) 2 ( μ 3 -OH) 2 (bdc) 2 (Hbdc) 2 ]·8H 2 O ( 1 ) possessing both hydrophobic and hydrophilic channels has been prepared by two synthetic methods which have subtle differences. Interestingly, 1 can reversibly transform to a layered coordination polymer Na{[(Cu 3 (pz) 3 ( μ 3 -OH)] 2 (bdc) 2 (Hbdc)}·DMF·21H 2 O ( 2 ) upon a single-crystal to single crystal (SCSC) process. 1 exhibits an 8-connected three-dimensional (3D) framework constructed by pentanuclear copper units and bdc linkers, while 2 shows a two-dimensional (2D) network built by triangular trinuclear copper units and bdc linkers. Furthermore, the magnetic properties of both 1 and 2 have been studied.