The Role of the Ligand‐to‐Metal Charge‐Transfer State in the Dipivaloylmethanate‐Lanthanide Intramolecular Energy Transfer Process

Abstract

Two new bis(dipivaloylmethanate)nitrato-bis(triphenylphosphine oxide)lanthanide(III) complexes [Eu(dpm) 2 (NO 3 )-(tppo) 2 ] (1) and [Tb(dpm) 2 (NO 3 )(tppo) 2 ] have been prepared in monomeric form. The structural behavior of these coordination compounds is significantly different from those of [Eu 2 (dpm) 6 ] and [Tb 2 (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 [a]

Effective photosensitized, electrosensitized, and mechanosensitized luminescence of lanthanide complexes

“…In Eu(III) complexes, the LMCT band from the S 0 state of the ligand to the Eu(III) ion leads to effective quenching of the excited Eu(III) complex [50][51][52][53][54][55] . The results of the detailed analysis of quenching by the LMCT band using a dinuclear Eu(III) complex have been reported 56,57 . Studies on photosensitized luminescence assisted by the LMCT band of lanthanide(III) complexes are limited; however, the photosensitized luminescence of some Eu (III) and Sm(III) complexes assisted by the LMCT bands have been reported as specific examples (Fig.…”

Effective Photo‐ and Triboluminescent Europium(III) Coordination Polymers with Rigid Triangular Spacer Ligands

“…[14,15] Molecular crystalsc omposed of lanthanide complexesa nd coordination polymers have recently been studied for effective triboluminescence. [16][17][18][19][20] While there have been extensived iscussions on the origin of triboluminescence from molecular crystals, somes tudies have indicatedacontribution of the piezoelectric effect upon breaking non-centrosymmetric bulk crystals. [21] The Eu III coordination polymers with triangular spacers in Figure 1a,b are expected to provide close packed structures and effective crystal cracking under mechanical stress.…”

Recent Advances on Metal-Based Near-Infrared and Infrared Emitting OLEDs

“…Among ligands, β-diketones are the most versatile ones, by their facile substitutions, their strong coordination ability, and π–π* transitions located in the UV region. When combined with O^N ancillary ligands, the coordination sphere around the lanthanide center is complete so that there is no space for high energy O–H or C–H oscillations of solvent molecules [114,115,116,117,118,119,120,121,122,123]. Indeed, lanthanide complexes are highly sensitive to their environment.…”

“…The geometry of Er complexes can greatly affect the emissive properties, and over the years, a great deal of efforts has been devoted to achieving the most favorable geometry. This is notably the case for erbium (III) β-diketonate complexes [113,114,115,116,117,118,119,120,121,122,123,124]. Fluorinated β-diketonate complexes with N^N-donor ancillary ligands have notably been developed for their remarkable solubility, allowing the design of solution-processed OLEDs with Er-4 [129] or Er-5 (See Figure 8) [130].…”