Synthesis, structural characterization and photoluminescent properties of 2D multilayer Cu + coordination polymers via C H⋯π and π⋯π interactions

Abstract Two Cu(I) coordination polymers, {[Cu(pmbb) 0.5 (4,4'-bipy) 0.5 (PPh 3 )](BF 4 ) (H 2 O) 2 } n ( 1 ) and {[Cu(pmbb) 0.5 (bpe) 0.5 (PPh 3 )](BF 4 )(DMF)} n ( 2 ) (pmbb =  N , N '-bis(pyridin-2-ylmethylene)biphenyl −4,4'-diamine, 4,4'-bipy = 4,4'-bipyridine, bpe = 1,2-bis(4-pyridyl)ethylene), PPh 3  = triphenyl phosphine), have been synthesized and characterized by IR, 1 H NMR, 13 C NMR, 31 P NMR, 19 F NMR, 11 B-NMR, TG and X-ray crystal structure analysis. The structural analysis shows that complexes 1 and 2 contain diverse and interesting 2D supramolecular networks based on inter-chain interactions. Complex 1 displays a 1D zig-zag chain and a 1D+1D→2D supramolecular network formed by intermolecular C H···π interaction. For 2 , each 1D zig-zag chain interacts with neighboring ones via intermolecular C H···π and π···π stacking interactions, leading to the formation of a 2D-stacking network. Furthermore, solid-state UV–Vis absorption spectra of complexes 1 and 2 indicate the existence of MLCT absorption. Complexes 1 and 2 show efficient luminescent emission peaks at 435 and 452 nm assigned to MLCT excited states, and the emission decay lifetimes are 20.82 μs for 1 and 20.72 μs for 2 , displaying strong room-temperature solid-state photoluminescence. Moreover, thermogravimetric analysis shows that the heat stability of polymers is 1 > 2 .