Intense blue emission and a reversible hypsochromic shift of luminescence caused by grinding based on silver(i) complexesElectronic supplementary information (ESI) available: Crystallographic data for X-ray structural analysis, NMR spectra, emission spectra, and details of the DFT calculations. CCDC 1472558 and 1472559. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6qi00254d

Silver( i ) complexes bearing N-heterocyclic carbene and diphenylphosphinobenzene ligands, [Ag(IPr)(dppbz)]BPh 4 ( 1 , IPr = bis(2,6-diisopropylphenyl)imidazole-2-ylidene, dppbz = 1,2-bis(diphenylphosphino)benzene), [Ag(IPr)(dfpbz)]BPh 4 ( 2 , dfpbz = 1,2-bis[di(4-fluorophenyl)phosphino]benzene), and [Ag(IPr)(dtbpbz)]BPh 4 ( 3 , dtbpbz = 1,2-bis[bis[3,5-di( tert -butyl)phenyl]phosphino]benzene), were newly synthesized and characterized. These complexes, especially 3 , exhibit intense blue emission in the solid state. The maximum wavelength and lifetime of the photoluminescence of 3 are 440 nm and 14 μs, respectively. The quantum yield of the photoluminescence of 3 in the solid state is 0.5, which is one of the highest values among blue-emissive silver( i ) complexes ever reported. Introduction of bulky tert -butyl groups at 3- and 5-positions of the phenyl groups in the diphosphine ligand plays a key role in both the blue-shift and the enhancement of the photoluminescence. Additionally, the reversible hypsochromic shift of the long-lived emission caused by the grinding process is observed for one of the complexes. Highly blue-emissive silver( i ) complexes bearing N-heterocyclic carbene and diphenylphosphinobenzene were newly synthesized. The reversible hypsochromic shift of the emission by the grinding process was observed.