Diverse architectures and luminescence properties of two novel copper(I) coordination polymers assembled from 2,6-bis[3-(pyrid-4-yl)-1,2,4-triazolyl]pyridine ligands

Two attractive Cu(I) coordination polymers with unique structures, namely, {[Cu-8(bptp)(4)]center dot 6H(2)O} (1) and {[Cu-5(bptp)(2)(CN)]center dot 2H(2)O} (2), have been successfully synthesized based on a V-shaped multidentate N-containing ligand 2,6-bis[3-(pyrid-4-yl)-1,2,4-triazolyl] pyridine (H(2)bptp). The structural analysis reveals that complex 1 displays a Cu-8 cluster-based infinite 1D ladder chain, in which each H(2)bptp ligand links four or five Cu(I) ions through nitrogen atoms of pyridine/triazole groups. Complex 2 features an unusual (3,4,5)-connected 3D topological network with the Schlafli symbol (4(2).5(4).6(3).7)(4(2).6(3).7)(5.6.8)(5.6(2).7.8(2)), which has not been reported before. The structural and dimensional diversity of the two complexes indicates that H2bptp exhibits strong coordination ability and diverse coordination modes. It is worth mentioning that the Cu center dot center dot center dot Cu distances in 1 and 2 are shorter than the sum of the van der Waals radii of copper(I) (2.80 angstrom), implying the metal-metal bonding interactions. What is more, the solid-state luminescence bands of 1 and 2 have also been investigated between 298 and 10 K. Interestingly, the low-energy emission bands of 1 and 2 exhibit yellow/orange-red luminescence, and their intensities increase gradually upon cooling.