Emissive Heterobimetallic Copper(I) Dicyanoaurate-Based Coordination Polymers

摘要

Five new Cu-I/[Au(CN)(2)](-)-based coordination polymer materials-Cu(py)(2)[Au(CN)(2)](1), Cu(PPh3)(MeCN)[Au(CN)(2)]center dot MeCN (2a), Cu(PPh3)(MeCN)[Au(CN)(2)] (2b), Cu-3(THT)(4)[Au(CN)(2)](3) (3a) and Cu(THT)[Au(CN)(2)] (3b)-were prepared and characterized in terms of their structural and photoluminescence properties, and thermal stability (py=pyridine, THT=tetrahydrothiophene). While 1 and 2a/2b adopted one-dimensional zig-zag chain structures with no Au center dot center dot center dot Au (aurophilic) bonding, 3a and 3b exhibited much more complex three-dimensional frameworks featuring numerous aurophilic interactions; bridging THT units formed either eight-membered Cu4S4 rings (3a) or helical (Cu/S)n chains (3b). When these materials are excited using a broad-band UV source (365 nm), they each emit light of a distinct colour (except for 2a): light green for 1, pale blue for 2b, deep blue for 3a, and violet for 3b (lambda(max)=506 nm (1), 464 nm (2b), 457 nm (3a) and 404 nm (3b)). The emission band in 1, 2b and 3b was assigned to Cu-I/ ligand/CN--based MLCT transitions, while the emission band of 3a appears to be influenced by the presence of the aurophilic interactions in the structure. Materials 1 and 3a lose their bound pyridine and THT, respectively, at 110 and 95 degrees C, respectively, indicating their potential utility as sensory materials.