Cyclic Triimidazole Derivatives: Intriguing Examples of Multiple Emissions and Ultralong Phosphorescence at Room Temperature

2017 ◽  
Vol 56 (51) ◽  
pp. 16302-16307 ◽  
Author(s):  
Elena Lucenti ◽  
Alessandra Forni ◽  
Chiara Botta ◽  
Lucia Carlucci ◽  
Clelia Giannini ◽  
...  
Keyword(s):  
Room Temperature ◽  
Phosphorescence At Room Temperature

The effect of imidazole on the enhancement of gadolinium-porphyrin phosphorescence at room temperature

2016 ◽  
Vol 45 (42) ◽  
pp. 16889-16895 ◽  
Author(s):  
Lixin Zang ◽  
Huimin Zhao ◽  
Jianyu Hua ◽  
Feng Qin ◽  
Yangdong Zheng ◽  
...  
Keyword(s):  
Room Temperature ◽  
Phosphorescence At Room Temperature

The mechanism for the 40-fold enhancement in Gd-HMME RTP intensity by adding imidazole and Gd3+ is revealed.

Electrophosphorescent Light Emitting Devices Using New Iridium(III) Complexes

2001 ◽  
Vol 708 ◽  
Author(s):  
Rupasree Ragini Das ◽  
Chang-Lyoul Lee ◽  
Jang-Joo Kim
Keyword(s):  
Room Temperature ◽  
Emission Spectra ◽  
Bidentate Ligands ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Host Materials ◽  
Donor Acceptor ◽  
Phosphorescence At Room Temperature ◽  
Triplet Emitter

ABSTRACTWe have synthesized a new tris-orthometalated Ir(mpp)3 and several bis-orthometalated Ir(III) complexes of 3-methyl-2-phenylpyridine(Hmpp). The influence of the methyl substituent in Hmpp and different ligand environments on the optical, electrochemical and electroluminescence properties of the orthometalated complexes are examined by varying the donor acceptor properties. This includes several uninegative bidentate ligands consisting of different organic functional groups. Absorption, excitation and emission spectra in solution and solid state of these complexes agree with a strong electronic excitation to 1MLCT in Ir(mpp)3 and preferably to 3MLCT in other complexes. These complexes demonstrate strong phosphorescence at room temperature with a lifetime of 1-2 μs. Multilayer organic light emitting devices using these complexes as the triplet emitter are studied using PVK (poly(9-vinyl carbazole)), CBP (4,4'-N,N'-dicarbazole-biphenyl) and TAZ (3-phenyl-4-(1'-napthyl)-5-phenyl-1,2,4-triazole) as the host materials. Ir(mpp)3exhibits quite different behavior in different host materials.

scholarly journals Synthesis, characterization and photophysical studies of cyclometalated Au(III) complexes

2015 ◽  
Author(s):  
◽  
Lakshmi Nilakantan
Keyword(s):  
Emission Spectrum ◽  
Room Temperature ◽  
Stokes Shift ◽  
Energy Difference ◽  
Single Step ◽  
Reductive Coupling ◽  
Tin Compounds ◽  
Synthetic Strategy ◽  
Dithiocarbamate Ligand ◽  
Phosphorescence At Room Temperature

We report here a series of room temperature emissive biphenyl cyclometalated gold (III) diethyl dithiocarbamate complexes (DEDT) having H, CF3, OMe and tBu substitutions on the biphenyl moiety. Synthesis of these complexes was accomplished by a single step reaction of the appropriate dilithiobiphenyl reagent with Au(DEDT)Cl2. The Au(DEDT)Cl2 complex played an important role in the success of our reaction, where the chelating sulfur ligand stabilizes the Au(III) center and keeps it intact without reducing to Au(I) or colloidal gold during the course of its reaction with the lithium compound. In comparison with other literature reported procedures for analogous Au(III) complexes, this methodology gave better yields with lesser number of reaction steps as well as without using toxic chemicals such as sodium cyanide or tin compounds. All of these complexes exhibit phosphorescence at room temperature as well as in low temperature glasses. While substitution on the biphenyl moiety by electron donating OMe and tBu groups red shifted the emission band when compared with hydrogen counterparts, the electron withdrawing CF3 groups made no difference. The emission from these complexes is mainly governed by the metal perturbed 3??* transitions of biphenyl and this assignment is well supported by the observed photo physical properties such as vibronic structured emission, lifetime in microseconds, large stokes shift, solvent independent emission spectrum as well as the oxygen quenching of the emission spectrum. Further DFT studies on these complexes also showed that the transition from LUMO+2 to HOMO. (3pi-pi*) is responsible for the emission. This is in contrast with lowest energy absorption which is mainly from HOMO-L+1 (LLCT). This is rationalized by the existence of a relaxed 3pi-pi* (-3.31 eV) state in lower energy when compared with the relaxed 3LLCT state (-1.61 eV) as well as the large energy difference between singlet and triplet pi-pi* states. We also hereby report the synthesis of a bis(diethyldithiocarbamate(DEDT) -S,S)-(naphthyl-1,8) digold(II) complex with a formal Au-Au bond. Our synthetic strategy involved reductive coupling via lithiation of dibromonaphthalene precursor followed by reaction with Au(DEDT)Cl2. This digold complex is unique when compared with known digold(II) complexes, which are traditionally synthesized by oxidative addition of halogen to digold(I) complexes. The digold complex has been characterized by NMR, XRD, UV-Vis and elemental analysis. DFT reasoned the UV-Vis absorption of complex 3 at 379 nm to the transition from sigmaAu-Au) orbital into sigma*(Au-Au) orbital with some contributions from the dithiocarbamate ligand (LMCT). However this complex shows no emission at 298 or 77 K. The lack of emission could possibly be due to low-lying non-emissive d-d states.

Phosphorescent labeling reagents of platinum(II) and palladium(II) coproporphyrin-II: Preparation and performance characteristics

2002 ◽  
Vol 06 (08) ◽  
pp. 533-543 ◽  
Author(s):  
Mirva M. Koskelin ◽  
Aleksi E. Soini ◽  
Niko J. Meltola ◽  
Gelii V. Ponomarev
Keyword(s):  
Room Temperature ◽  
Time Resolved Fluorescence ◽  
Reactive Group ◽  
Time Resolved ◽  
Emission Efficiency ◽  
Alkaline Conditions ◽  
Phosphorescence At Room Temperature ◽  
And Performance ◽  
Derivatives Of ◽  
Coproporphyrin I

Synthesis of monofunctional derivatives of platinum(II) and palladium(II) coproporphyrin-II with the isothiocyanato reactive group is presented. The compounds exhibit strong phosphorescence at room temperature in deoxygenated aqueous solutions and they enable facile covalent labeling of proteins and other biomolecules under slightly alkaline conditions. The performance of the compounds as phosphorescent labeling reagents is studied and the results are considered in relation to the results for the respective labeling reagent of coproporphyrin-I isomer. The results show that the derivatives of coproporphyrin-II exhibit similar reactivity and emission efficiency to that of the derivatives of coproporphyrin-I isomers. Thus, the coproporphyrin-II derivatives serve as alternative labels to coproporphyrin-I in the design of sensitive bioassays based on phosphorescence and time-resolved fluorescence detection.

Twenty-fold Enhancement of Gadolinium-Porphyrin Phosphorescence at Room Temperature by Free Gadolinium Ion in Liquid Phase

2015 ◽  
Vol 119 (50) ◽  
pp. 28111-28116 ◽  
Author(s):  
Lixin Zang ◽  
Huimin Zhao ◽  
Yangdong Zheng ◽  
Feng Qin ◽  
Jianting Yao ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Room Temperature ◽  
Phosphorescence At Room Temperature

scholarly journals Halogenation of a twisted non-polar π-system as a tool to modulate phosphorescence at room temperature

2021 ◽  
Author(s):  
Giliandro Farias ◽  
Cristian A.M. Salla ◽  
Aydemir Murat ◽  
Ludmilla Sturm ◽  
Pierre Dechambenoit ◽  
...  
Keyword(s):  
Room Temperature ◽  
The Other ◽  
Thermally Activated ◽  
Phosphorescence At Room Temperature ◽  
Triplet Triplet Annihilation

Halogenation of a twisted three-fold symmetric hydrocarbon with F, Cl or Br leads to strong modulation of triplet-triplet annihilation and dual phosphorescence, one thermally activated and the other very persistent...

Fluorescence, Phosphorescence, and Delayed Fluorescence of Benzil in Imidazolium Ionic Liquids

2012 ◽  
Vol 65 (9) ◽  
pp. 1291 ◽  
Author(s):  
Dinesh Chandra Khara ◽  
Anunay Samanta
Keyword(s):  
Ionic Liquids ◽  
Room Temperature ◽  
Emission Spectra ◽  
Wavelength Dependence ◽  
Delayed Fluorescence ◽  
Excitation Wavelength ◽  
Imidazolium Ionic Liquids ◽  
Thermally Activated ◽  
Phosphorescence At Room Temperature ◽  
The Media

Temperature dependence of the emission behaviour of benzil has been studied in three imidazolium ionic liquids differing in their polarity and viscosity. Room temperature absorption and steady-state emission spectra suggest that the ground and excited state conformers of benzil in ionic liquids are similar to those in conventional organic solvents. The non-degassed solutions of benzil in ionic liquids show phosphorescence at room temperature in contrast to conventional solvents where phosphorescence is commonly observed in degassed conditions. This study reveals that a thermally activated reverse intersystem crossing (T1↝S1) process is responsible for the drastic change in phosphorescence intensity with temperature in ionic liquids. The rate constant () of this process is found to be dependent on the polarity of the media and is 5 times higher in most polar ionic liquids. The evidence of the presence of multiple conformers of benzil in frozen conditions is obtained from the excitation wavelength dependence of the phosphorescence spectra.

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