Anion-directed structures and luminescences of two Cu(I) coordination polymers based on bipyrazole

Two anion-directed Cu(I) coordination polymers (CPs), namely, [Cu-2(TMBP)(2)(mu-CN)(I)center dot(3.5H(2)O)(n) (1, TMBP = 3,3',5,5'-tetramethyl-4,4'-bipyrazole) and [Cu-2(TMBP)(2)(mu-SCN)(mu-CN)](n) (2), were synthesized through solvothermal method and characterized by single crystal and powder X-ray diffraction, elemental analysis. 1 is a 3-dimension framework with nanocavity and (4(2).6(3).8) topology while 2 is a 2-dimension network with 3-fold penetration and (6(2).10)(6.6) topology, the difference in structure being related to the anions (I- or SCN-) included in precursor solution. Furthermore, 1 exhibits strong blue emission when excited at 315 nm, which should be resulted from 1 to Cu(I) charge transfer; however, no obvious luminescence was observed in case of 2. This work emphasizes a strategy of anion-directed synthesis of CPs for tuning photoluminescent property.