Structural Diversity and Properties of Coordination Polymers Built from a Rigid Octadentenate Carboxylic Acid

By using a rigid octadentenate carboxylate linker 5,5′,5″,5″′-silanetetrayltetraisophthalic acid (H 8 L), three new microporous coordination polymers, namely, [Cu 4 L(H 2 O) 4 ]·2DMF·10H 2 O ( 1 ), [Zn 5 L 2 (H 2 O) 4 ][NH 2 (CH 3 ) 2 ] 6 ·2DMF·4H 2 O ( 2 ), and [Cd 3 (H 2 L) 2 ][NH 2 (CH 3 ) 2 ] 6 ·4DMF·14H 2 O ( 3 ), were solvothermally synthesized and structurally characterized. Compound 1 is a 3D framework built from a square paddlewheel [Cu 2 (O 2 CR) 4 ] and a 8-connected cube L ligand to give a (4,8)-connected scu structure. Compound 2 is a 3D 4-nodal (4,4,4,8)-connected network with small 1D channels built on three tetrahedral Zn units and a 8-connecting ligand L. Compound 3 possesses a 3D structure with a (4,4,6)-connected net built on two tetrahedral Cd units and a 6-connecting ligand H 2 L 6– . All the three compounds consist of large solvent accessible voids, but only compound 1 possesses permanent porosity as confirmed by N 2, H 2, O 2, CO 2 and CH 4 gas adsorption measurements. Compounds 2 and 3 exhibited strong blue fluorescent emissions with a peak at 414 and 412 nm, respectively, at RT upon excitation owing to a ligand-centered excited state.