Synthesis and structural characterization of different topological coordination polymers based on tunable Cu 4Br 4− mI m secondary building units and macrocyclic azacalixaromatics

Abstract

The coordination self-assembly between the macrocyclic ligand tetraazacalix[4]pyrimidine (TAPM) with cubane-like copper halides (Cu 4 X 4) produced five coordination polymers 1– 5 {Cu 4Br 4− m I m (TAPM)} n ( m=0 ( 1), 1 ( 2), 2 ( 3), 3 ( 4) and 4 ( 5)). X-ray single crystal analysis revealed that the Br:I ratio in the Cu 4 X 4 cores serves as a controlling factor to fine-tune the geometries of Cu 4 X 4 and therefore induce the conformation variation of tetraazacalix[4]pyrimidine. Consequently, two different topological nets, dia and lcs, were successfully constructed based on tetrahedrally coordinated Cu 4 X 4 secondary building units and the flexible macrocyclic quadridentate ligand TAPM. The structure details of 1– 5 as porous materials are analyzed, which shows a solvent accessible volume within the range of 27−35%. Compounds 1– 5 exhibit luminescence properties with the peak maximum at around 476−488 nm.