4,5-Bis(diphenylphosphino)-9,9-dimethylxanthene: Versatile Ligand for Luminescent Material Applications

4,5-Bis(diphenylphosphino)-9,9-dimethylxanthene is a metal chelating ligand for catalysis. 4,5-Bis(diphenylphosphino)-9,9-dimethylxanthene is also a ligand used in the synthesis of heterocycles by palladium-catalyzed C-N cross coupling of 3-bromothiophenes with 2-aminopyridines. The compound has been used in a ruthenium-catalyzed alkylation of active methylene compounds with alcohols.

Herein, a new β-diketonate ligand, namely, 1-(4-(diphenylphosphino)phenyl)-4,4,5,5,5-pentafluoropentane-1,3-dione (DPPFH) has been synthesized and utilized for the construction of an antenna complex of Eu3+ [Eu(DPPF)3(DDXPO)] in the presence of a chelating ligand, 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene oxide (DDXPO). The developed Eu3+ compound has been well characterized and investigated the photophysical properties. The designed Eu3+ complex displays bright red luminescence upon irradiation at the ligand-centered band at 375 nm with a quantum yield of 39% in the solid-state. Interestingly, the ternary Eu3+ complex also exhibits brilliant triboluminescence in the daylight, which could be useful in the design of pressure and damage detection probes. In addition, the newly obtained Eu3+ complex was embedded into a PMMA matrix to form highly luminescent films having quantum yields as high as 45–50%. These plastic materials display enhanced thermal stability as compared to parent compound.

Reference

[1] RAJ D B A, BIJU S, REDDY M L P. 4,4,5,5,5-Pentafluoro-1-(9H-fluoren-2-yl)-1,3-pentanedione complex of Eu3+ with 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene oxide as a promising light-conversion molecular device†[J]. Dalton Transactions, 2009, 36. DOI:10.1039/B907031A.

2. Raj DB, Francis B, Reddy ML, Butorac RR, Lynch VM, Cowley AH. Highly luminescent poly(methyl methacrylate)-incorporated europium complex supported by a carbazole-based fluorinated β-diketonate ligand and a 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene oxide co-ligand. Inorg Chem. 2010; 49(19): 9055-9063.