scholarly journals Light driven isomerization of coordinated ligand and modulation offac-[Re(CO)3(phen)(trans-bpe)]PF6photoluminescence in rigid media

2001 ◽  
Vol 3 (3) ◽  
pp. 143-164 ◽  
Author(s):  
Melina Kayoko Itokazu ◽  
André Sarto Polo ◽  
Neyde Yukie Murakami Iha
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Photophysical Properties ◽  
Acetonitrile Solution ◽  
Solid Films ◽  
Spectral Changes ◽  
Rhenium Complex ◽  
Photostationary State ◽  
Ligand Charge Transfer ◽  
Enhanced Luminescence

The excited state reactivity and photophysical properties offac-[Re(CO)3(phen)(L)]PF6(phen = 1,10-phenanthroline, L =trans- orcis-1,2-bis(4-pyridyl)ethylene, bpe) in PMMA (poly(methyl methacrylate)) films have been investigated and compared with those in acetonitrile solution.313 or 365 nm irradiation of the rhenium complex in PMMA leads to UV-vis spectral changes due to thetrans→cisisomerization of the coordinated bpe ligand. Thefac-[Re(CO)3(phen)(cis-bpe)]+product presents a markedly enhanced luminescence due to a lower lying metal-to-ligand charge transfer (MLCT) excited state in thecisisomer. This emitting property can be conveniently applied as a probe or sensor.Thecisis omer ratio in the photostationary state (PSS) is substantially smaller in solid films than in solution. The photochemical behavior of the freetrans-1,2-bis(4-pyridyl)ethylene in PMMA is also reported to establish comparisons with the investigation carried out in acetonitrile solution as well as with the behavior of the coordinated ligand.

Temperature dependence of photophysical properties of a dinuclear C^N-cyclometalated Pt(ii) complex with an intimate Pt–Pt contact. Zero-field splitting and sub-state decay rates of the lowest triplet

2018 ◽  
Vol 20 (38) ◽  
pp. 25096-25104 ◽  
Author(s):  
Joseph C. Deaton ◽  
Arnab Chakraborty ◽  
Rafal Czerwieniec ◽  
Hartmut Yersin ◽  
Felix N. Castellano
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Photophysical Properties ◽  
Decay Rates ◽  
Zero Field ◽  
Triplet Excited State ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Ligand Charge Transfer ◽  
Metal Metal

A dinuclear Pt(ii) complexes exhibits an unusually large zero field splitting in its metal–metal-to-ligand charge transfer triplet excited state.

scholarly journals Synthesis and Photophysical Properties of Some Conjugated Polymers Functionalized with Ruthenium Polypyridine Complexes

1997 ◽  
Vol 488 ◽  
Author(s):  
Po King Ng ◽  
Wai Yue Ng ◽  
Xiong Gong ◽  
Wai Kin Chan
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Conjugated Polymers ◽  
Conjugated Polymer ◽  
Photophysical Properties ◽  
Polymer Systems ◽  
Ligand Charge Transfer ◽  
Palladium Catalyzed ◽  
Polypyridine Complexes ◽  
Ruthenium Polypyridine

AbstractA series of conjugated polymers functionalized with different ruthenium polypyridine metal complexes were synthesized by the palladium catalyzed reaction. Two conjugated polymer systems have been studied: 1. poly(phenylenevinylene) with bis(2,2':6',2”-terpyridine) ruthenium (II) on the mainchain and 2. quinoxaline based polymers with tris(2,2'-bipyridine) ruthenium (II). The ruthenium polypyridine complexes exhibit a long-lived metal to ligand charge transfer excited state which can enhance the photosensitivity of the resulting polymers. Different physical properties such as the photoconductivity and charge mobility in these polymers are also studied.

Synthesis and Photophysical Properties of New Three-Coordinate N-Heterocyclic Carbene Copper Complex

2016 ◽  
Vol 878 ◽  
pp. 18-21
Author(s):  
Shao Bo Liu ◽  
Cheng Yi ◽  
Hong Ying Xia ◽  
Feng Zhao
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Absorption Band ◽  
Energy Absorption ◽  
Copper Complex ◽  
Room Temperature ◽  
Photophysical Properties ◽  
Emission Spectrometry ◽  
Emission Maximum ◽  
Ligand Charge Transfer

A three-coordinateopper (I) complex supported by N-heterocyclic carbene (NHC) ligand and bis [2-(diphenylphosphino) phenyl] ether (POP) ligand were successfully reported and characterized. The corresponding photophysical properties were investigated using UV-vis and emission spectrometry. The lowest-energy absorption band at 343 nm was assigned to metal-to-ligand charge transfer (MLCT) transtion. The emission maximum located at 470 nm upon excitation at 290 nm in PMMA films at room temperature originates from the typical 3MLCT excited state.

Synthesis, Characterization and Photophysical Properties of Rhenium(I) Complexes Containing 4,5-Diazafluorene Ligan

2011 ◽  
Vol 239-242 ◽  
pp. 2612-2615
Author(s):  
Jie Xiu Wang ◽  
Feng Zhao
Keyword(s):  
Charge Transfer ◽  
Fluorescence Spectra ◽  
Photophysical Properties ◽  
Absorption And Fluorescence Spectra ◽  
Rhenium Complexes ◽  
H Nmr ◽  
Ligand Charge Transfer

Two related tricarbonyl rhenium complexes with the formula of [Re(CO)3(L)Cl], where L=4,5-diazafluoren-9-one (Dafo-Re) and 9-(phenylamino)-4,5-diazafluoren (PADF-Re) were successfully synthesized with the aim to explore the effect of the geometry of Dafo on Rhenium(I) coordination, and characterized by1H NMR. Photophysical behaviors are investigated by UV–vis absorption and Fluorescence spectra. The two complexes Dafo-Re and PADF-Re show metal-to-ligand charge transfer absorptions at ca.391nm, ca.394 nm and emissions at ca.492nm, ca.470nm, respectively.

Electroabsorption spectra of push–pull porphyrins in solution and in solid films

2015 ◽  
Vol 19 (01-03) ◽  
pp. 527-534
Author(s):  
Kamlesh Awasthi ◽  
Hung-Yu Hsu ◽  
Hung-Chu Chiang ◽  
Chi-Lun Mai ◽  
Chen-Yu Yeh ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Charge Transfer ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Ground State ◽  
Benzene Solution ◽  
Solid Films ◽  
The One ◽  
Interfacial Charge

Polarized electroabsorption (E-A) spectra of highly efficient porphyrin sensitizers (YD2 and YD2-oC8) have been measured in benzene solution. Polarized E-A spectra of these push–pull porphyrins embedded in poly(methyl methacrylate) films or sensitized on TiO 2 films are also observed. Based on the analysis of the E-A spectra, the magnitude of the electric dipole moment both in the ground state and in the lowest excited state have been evaluated in solution and in solid films. The electric dipole moment in the excited state of these compounds is very large on TiO 2 films, suggesting the interfacial charge transfer on TiO 2 surface following photoexcitation of porphyrin dyes. The electric dipole moment in the excited state evaluated from the E-A spectra is very different from the one evaluated from the electrophotoluminescence spectra on TiO 2, suggesting that the strong local field of TiO 2 films is applied to the fluorescing dyes attached to TiO 2 films.

Synthesis, Characterization and Optical Properties Based on a Novel Re(I) Emitter with Bulky Building Block

2011 ◽  
Vol 295-297 ◽  
pp. 373-377 ◽  
Author(s):  
Tie Nan Zang ◽  
Xiao Li ◽  
Lian Shui Yu ◽  
Ji Ping Ru ◽  
Hai Jun Chi ◽  
...  
Keyword(s):  
Optical Properties ◽  
Photophysical Properties ◽  
Decomposition Temperature ◽  
Organic Light Emitting Diodes ◽  
Absorption Bands ◽  
Light Emitting ◽  
H Nmr ◽  
Rhenium Complex ◽  
Organic Light ◽  
Ligand Charge Transfer

A novel rhenium complex material, i.e., Re-APPP, (APPP, 2,3-acenaphtho[1,2-b]pyrazino [2,3-f][1,10]phenanthroline) was designed, synthesized in five steps from commercially available starting materials and characterized by FTIR,1H NMR and mass spectroscopy. The photophysical properties of this complex were studied. The absorption bands centered at ca. 326, 366 and 450nm of Re-APPP were attributed to the ligand-centered p→p* transition and the metal-to-ligand charge transfer dπ(Re)→π*(APPP) transition, respectively. Re-APPP was thermally stable with high decomposition temperature of 302°C. The organic light-emitting diodes using Re-APPP as a dopant emitter with the structures of ITO/m-MTDATA(10nm)/NPB(20nm)/CBP: Re-APPP(30nm)/BCP(10nm)/Alq3(30nm)/LiF(1nm)/Al(100nm) were fabricated and a broad electroluminescent peak at 550nm was observed. More importantly, the devices exhibited very small efficiency roll-off of only ca.45% which was probably attributed to its short luminescent lifetime.

A density functional theory and spectroscopic study of intramolecular quenching of metal-to-ligand charge-transfer excited states in some mono-bipyridine ruthenium(II) complexes

2014 ◽  
Vol 92 (10) ◽  
pp. 996-1009 ◽  
Author(s):  
Shivnath Mazumder ◽  
Ryan A. Thomas ◽  
Richard L. Lord ◽  
H. Bernhard Schlegel ◽  
John F. Endicott
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Charge Transfer ◽  
Excited States ◽  
Lower Energy ◽  
Density Functional ◽  
Dimethyl Sulfide ◽  
Intramolecular Electron Transfer ◽  
Functional Theory ◽  
Ligand Charge Transfer

The complexes [Ru(NCCH3)4bpy]2+ and [Ru([14]aneS4)bpy]2+ ([14]aneS4 = 1,4,8,11-tetrathiacyclotetradecane, bpy = 2,2′-bipyridine) have similar absorption and emission spectra but the 77 K metal-to-ligand charge-transfer (MLCT) excited state emission lifetime of the latter is less than 0.3% that of the former. Density functional theory modeling of the lowest energy triplet excited states indicates that triplet metal centered (3MC) excited states are about 3500 cm−1 lower in energy than their 3MLCT excited states in both complexes. The differences in excited state lifetimes arise from a much larger coordination sphere distortion for [Ru(NCCH3)4bpy]2+ and the associated larger reorganizational barrier for intramolecular electron transfer. The smaller ruthenium ligand distortions of the [Ru([14]aneS4)bpy]2+ complex are apparently a consequence of stereochemical constraints imposed by the macrocyclic [14]aneS4 ligand, and the 3MC excited state calculated for the unconstrained [Ru(S(CH3)2)4bpy]2+ complex (S(CH3)2 = dimethyl sulfide) is distorted in a manner similar to that of [Ru(NCCH3)4bpy]2+. Despite the lower energy calculated for its 3MC than 3MLCT excited state, [Ru(NCCH3)4bpy]2+ emits strongly in 77 K glasses with an emission quantum yield of 0.47. The emission is biphasic with about a 1 μs lifetime for its dominant (86%) emission component. The 405 nm excitation used in these studies results in a significant amount of photodecomposition in the 77 K glasses. This is a temperature-dependent biphotonic process that most likely involves the bipyridine-radical anionic moiety of the 3MLCT excited state. A smaller than expected value found for the radiative rate constant is consistent with a lower energy 3MC than 3MLCT state.

Ultrafast excited state dynamics of [Cr(CO)4(bpy)]: revealing the relaxation between triplet charge-transfer states

RSC Advances ◽  
2016 ◽  
Vol 6 (25) ◽  
pp. 20507-20515 ◽  
Author(s):  
Fei Ma ◽  
Martin Jarenmark ◽  
Svante Hedström ◽  
Petter Persson ◽  
Ebbe Nordlander ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Absorption Spectroscopy ◽  
Dft Calculation ◽  
Pump Probe ◽  
Excited State Dynamics ◽  
Mlct Transition ◽  
Ligand Charge Transfer ◽  
Probe Absorption

Ultrafast excited state dynamics of [Cr(CO)4(bpy)] upon metal-to-ligand charge-transfer (1MLCT) transition have been studied by pump-probe absorption spectroscopy and DFT calculation.

scholarly journals Sensitization of ultra-long-range excited-state electron transfer by energy transfer in a polymerized film

2012 ◽  
Vol 109 (38) ◽  
pp. 15132-15135 ◽  
Author(s):  
Akitaka Ito ◽  
David J. Stewart ◽  
Zhen Fang ◽  
M. Kyle Brennaman ◽  
Thomas J. Meyer
Keyword(s):  
Electron Transfer ◽  
Energy Transfer ◽  
Excited State ◽  
Charge Transfer ◽  
Long Range ◽  
Methyl Viologen ◽  
Polymer Network ◽  
Triplet Energy ◽  
Ligand Charge Transfer ◽  
Triplet Energy Transfer

Distance-dependent energy transfer occurs from the Metal-to-Ligand Charge Transfer (MLCT) excited state to an anthracene-acrylate derivative (Acr-An) incorporated into the polymer network of a semirigid poly(ethyleneglycol)dimethacrylate monolith. Following excitation, to Acr-An triplet energy transfer occurs followed by long-range, Acr-3An—Acr-An → Acr-An—Acr-3An, energy migration. With methyl viologen dication (MV2+) added as a trap, Acr-3An + MV2+ → Acr-An+ + MV+ electron transfer results in sensitized electron transfer quenching over a distance of approximately 90 Å.

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