The Role of the Ligand‐to‐Metal Charge‐Transfer State in the Dipivaloylmethanate‐Lanthanide Intramolecular Energy Transfer Process. Issue 18 (2nd June 2015)

• Record Type: Journal Article
• Authors: Miranda, Yolanda C.; Pereira, Leide L. A. L.; Barbosa, José H. P.; Brito, Hermi F.; Felinto, Maria C. F. C.; Malta, Oscar L.; Faustino, Wagner M.; Teotonio, Ercules E. S.
• Is Part Of: European journal of inorganic chemistry. Issue 18(2018)
• Page Start: 3019
• Page End: 3027
• Publication Date: 2015-06-02
• Subjects: Lanthanides -- Charge transfer -- Energy transfer -- Luminescence -- Tribo­luminescence; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201500263
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: Two new bis(dipivaloylmethanate)nitrato‐bis(triphenylphosphine oxide)lanthanide(III) complexes [Eu(dpm)2 (NO3 )(tppo)2 ] (1 ) and [Tb(dpm)2 (NO3 )(tppo)2 ] have been prepared in monomeric form. The structural behavior of these coordination compounds is significantly different from those of [Eu2 (dpm)6 ] and [Tb2 (dpm)6 ] dimeric complexes. The photoluminescent properties of the monomeric and dimeric complexes are dependent on the energy positions of the low‐lying ligand‐to‐metal charge‐transfer (LMCT) state, which may be correlated with the chelating and chelate bridging coordination modes of the dpm ligand, respectively. The monomeric complex presents higher luminescence intensity than the dimeric complex due to the higher energy of the LMCT state in this system. Although the excited energy levels of the Eu III ion in complex1 undergo efficient depopulation by LMCT, the same is not observed for the 5 D0 emitting level, which presents values of the emitting lifetime that are almost temperature independent. The triboluminescence phenomenon of the [Ln(dpm)2 (NO3 )(tppo)2 ] complex is also discussed. Abstract : New Eu III and Tb III compounds containing the dipivaloylmethanate (dpm) ligand have been synthesized and characterized. Ligand‐to‐metal energy transfer and the role of the charge transfer state on the luminescent properties have been investigated. The luminescent properties have been compared with those of dimeric complexes containing the dpm ligand