Red Luminescent Eu(III) Coordination Bricks Excited on Blue LED Chip

Three types of red luminescent Eu­(III) complexes with Schiff base and hfa ligands (hfa: hexafluoroacetylacetonate), mononuclear [Eu­(hfa)₂(OAc)­(salen)₂] (OAc: acetate anion, salen: <i>N,N</i>′-bis­(salicylidene)­ethylenediamine), brick-type [Eu₂(hfa)₄(OAc)₂(salbn)₂] (salbn: <i>N,N</i>′-bis­(salicylidene)-1,4-butanediamine), and polynuclear [Eu­(hfa)₂(OAc)­(salhen)]_<i>n</i> (salhen: <i>N,N</i>′-bis­(salicylidene)-1,6-hexanediamine) are reported for white light-emitting diode (LED) devices. Among these complexes, brick-type [Eu₂(hfa)₄(OAc)₂(salbn)₂] excited by blue light (460 nm) exhibits the photosensitized quantum yield (Φ_π–π* = 47%) and remarkably high efficiency of sensitization (η_sens = 96%). The efficiency of sensitization is caused by the excited state based on ligand–ligand interaction between the Schiff base and hfa ligands in Eu­(III) complexes. To fabricate LED devices, the red luminescent [Eu₂(hfa)₄(OAc)₂(salbn)₂] was mounted on an InGaN blue LED chip

Luminescent Coordination Glass: Remarkable Morphological Strategy for Assembled Eu(III) Complexes

Syntheses of novel luminescent Eu­(III) coordination glasses <b>1</b> ([Eu­(hfa)₃(<i>o</i>-dpeb)]₂), <b>2</b> ([Eu­(hfa)₃(<i>m</i>-dpeb)]₃), and <b>3</b> ([Eu­(hfa)₃(<i>p</i>-dpeb)]_<i>n</i>) are reported. They are composed of Eu­(III) ions, hexafluoroacetylacetonato (hfa) ligands, and unique bent-angled phosphine oxide (<i>o</i>-, <i>m</i>-, <i>p</i>-dpeb) ligands with ethynyl groups. Their coordination structures and glass formability are dependent on the regiochemistry of substitution in regard to the internal benzene core. Single-crystal X-ray analyses and DFT calculation reveals dinuclear, trinuclear, and polymer structures for Eu­(III) coordination glasses <b>1</b>, <b>2</b>, and <b>3</b>, respectively. Those compounds show characteristic glass-transition (<i>T</i>_g = 25–96 °C) and strong luminescence properties (Φ_Ln = 72–94%)

Enhanced Electric Dipole Transition in Lanthanide Complex with Organometallic Ruthenocene Units

Enhanced luminescence of a lanthanide complex with dynamic polarization of the excited state and molecular motion is introduced. The luminescent lanthanide complex is composed of one Eu­(hfa)₃ (hfa, hexafluoroacetylacetonate) and two phosphine oxide ligands with ruthenocenyl units Rc, [Eu­(hfa)₃(RcPO)₂] (RcPO = diphenylphosphorylruthenocene). The ruthenocenyl units in the phosphine oxide ligands play an important role of switching for dynamic molecular polarization and motion in liquid media. The oxidation states of the ruthenocenyl unit (Rc­(1+)/Rc­(1+)) are controlled by potentiostatic polarization. Eu­(III) complexes attached with bidentate phosphine oxide ligands containing ruthenocenyl units, [Eu­(hfa)₃(RcBPO)] (RcBPO = 1,1′-bis­(diphenylphosphoryl)­ruthenocene), and with bidentate phosphine oxide ligands, [Eu­(hfa)₃(BIPHEPO)] (BIPHEPO =1,1′-biphenyl-2,2′-diylbis­(diphenylphosphine oxide), were also prepared as references. The coordination structures and electrochemical properties were analyzed using single crystal X-ray analysis, cyclic voltammetry, and absorption spectroscopy measurements. The luminescence properties were estimated using an optoelectrochemical cell. Under potentiostatic polarization, a significant enhancement of luminescence was successfully observed for [Eu­(hfa)₃(RcPO)₂], while no spectral change was observed for [Eu­(hfa)₃(RcBPO)]. In this study, the remarkable enhanced luminescence phenomena of Eu­(III) complex based on the dynamic molecular motion under potentiostatic polarization have been performed

Enhanced Electric Dipole Transition in Lanthanide Complex with Organometallic Ruthenocene Units

Enhanced luminescence of a lanthanide complex with dynamic polarization of the excited state and molecular motion is introduced. The luminescent lanthanide complex is composed of one Eu­(hfa)₃ (hfa, hexafluoroacetylacetonate) and two phosphine oxide ligands with ruthenocenyl units Rc, [Eu­(hfa)₃(RcPO)₂] (RcPO = diphenylphosphorylruthenocene). The ruthenocenyl units in the phosphine oxide ligands play an important role of switching for dynamic molecular polarization and motion in liquid media. The oxidation states of the ruthenocenyl unit (Rc­(1+)/Rc­(1+)) are controlled by potentiostatic polarization. Eu­(III) complexes attached with bidentate phosphine oxide ligands containing ruthenocenyl units, [Eu­(hfa)₃(RcBPO)] (RcBPO = 1,1′-bis­(diphenylphosphoryl)­ruthenocene), and with bidentate phosphine oxide ligands, [Eu­(hfa)₃(BIPHEPO)] (BIPHEPO =1,1′-biphenyl-2,2′-diylbis­(diphenylphosphine oxide), were also prepared as references. The coordination structures and electrochemical properties were analyzed using single crystal X-ray analysis, cyclic voltammetry, and absorption spectroscopy measurements. The luminescence properties were estimated using an optoelectrochemical cell. Under potentiostatic polarization, a significant enhancement of luminescence was successfully observed for [Eu­(hfa)₃(RcPO)₂], while no spectral change was observed for [Eu­(hfa)₃(RcBPO)]. In this study, the remarkable enhanced luminescence phenomena of Eu­(III) complex based on the dynamic molecular motion under potentiostatic polarization have been performed