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Bright Cyan Phosphorescence of a (Phosphane)copper(I) Complex of the Trihydridopyrazolylborate Ligand H 3 B(3,5‐Ph 2 Pz) –
Author(s) -
van Dijkman Thomas F.,
de Bruijn Hans M.,
Siegler Maxime A.,
Bouwman Elisabeth
Publication year - 2015
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201500812
Subject(s) - chemistry , phosphorescence , ligand (biochemistry) , crystallography , copper , hydride , metal , medicinal chemistry , fluorescence , biochemistry , physics , receptor , organic chemistry , quantum mechanics
The ligand trihydrido(3,5‐diphenylpyrazol‐1‐yl)borate([Mp Ph2 ] – ) has been synthesized from 3,5‐diphenylpyrazole and sodium borohydride in N , N ‐dimethylformamide. By using this ligand, three phosphane‐stabilized copper(I) complexes [Cu(Mp Ph2 )(L 2 )] [L 2 = (PPh 3 ) 2 , 1,2‐bis(diphenylphosphanyl)ethane (dppe), or 1,2‐bis(diphenylphosphanyl)benzene (dppbz)] were synthesized. The complexes were characterized by multinuclear NMR spectroscopy, IR spectroscopy, and X‐ray crystallography. The crystal structures of these complexes show that the copper ions are in trigonal‐pyramidal geometries with the apical position formed by agostic Cu–H interactions between the Cu I center and one of the hydride atoms of the borate ligand. Complexes [Cu(Mp Ph2 )(PPh 3 ) 2 ] and [Cu(Mp Ph2 )(dppbz)] are mononuclear, whereas complex [Cu 2 (Mp Ph2 ) 2 (μ‐dppe) 2 ] is dinuclear with bridging dppe ligands. In the solid state, fluorescent emissions are observed in [Cu(Mp Ph2 )(PPh 3 ) 2 ] and [Cu 2 (Mp Ph2 ) 2 (μ‐dppe) 2 ] but not in [Cu(Mp Ph2 )(dppbz)], which exhibits bright cyan phosphorescence at room temperature that shifts to green when the sample is cooled to 77 K. The phosphorescence of [Cu(Mp Ph2 )(dppbz)] is attributed to mixed interligand and metal‐to‐ligand charge transfer 3 (MLCT + π–π*) excited states.