Solvent Directed Synthesis of Molecular Cage and Metal Organic Framework of Copper(II) Paddlewheel Cluster

Abstract

A solvothermal reaction of a clip-type dicarboxylic acid H2DCA [3,3′-((5-nitroisophthaloyl)bis(azanediyl))-dibenzoic acid] and Cu(NO3)2 in equimolar ratio in dimethylformamide (DMF) yielded MOF(CuCG1) which was formed by interlinking [4+2] self-assembled polyhedral cages via coordination between amide moiety present in the linker and the axial position of copper paddlewheel Cu2(CO2)4. Upon a change in the solvent from DMF to DMA [dimethylacetamide] the interlinking among the polyhedra was successfully terminated to get single crystals of a discrete coordination cage with DMA bound to axial position of Cu(II) (CuCG2). Similar termination of the interlinking was also achieved by a fast crystallization process to get discrete architecture CuCG1.