Structural Diversity of Copper(I) Cluster-Based Coordination Polymers with Pyrazine-2-thiol Ligand

Six novel copper(I) cluster-based coordination polymers (CPs) [Cu 9 (pzt) 7 Cl 2 ] n ( 1 ), [Cu 2 (pzt)Cl] n ( 2 ), [Cu 4 (pzt) 3 Br] n ( 3 ), [Cu(pzt)] n ( 4 ), [Cu 4 (pzt) 3 I] n ( 5 ), and [Cu 7 (pzt) 6 I] n ( 6 ) were solvothermally synthesized using Hpzt (Hpzt = pyrazine-2-thiol) ligand and well-characterized by elemental analysis, infrared (IR) spectroscopy, powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction (SCXRD). Six CPs exhibit either 2D ( 4 and 6 ) or 3D ( 1 – 3, and 5 ) network based on diverse multinuclear {Cu x S y } clusters. The structural evolutions of 1 – 6 are greatly influenced by types of metal halides and the ligand-to-metal molar ratio used in the reaction. Among them, compound 1 displays interesting temperature-dependent photoluminescence arising from triplet cluster-centered ( 3 CC) excited state from the cluster metal core. Compounds 1 – 6 also exhibit photocurrent responses upon visible-light illumination (λ = 420 nm) in the order 6 > 5 > 3 > 1 > 4 > 2 . This work not only shows the structural diversity of {Cu x S y } clusters-based CPs but also provides an interesting insight into structural modulation using crystal engineering concept.