Excited States of Nitro-Polypyridine Metal Complexes and Their Ultrafast Decay. Time-Resolved IR Absorption, Spectroelectrochemistry, and TD-DFT Calculations offac-[Re(Cl)(CO)3(5-Nitro-1,10-phenanthroline)]

2005 ◽  
Vol 109 (28) ◽  
pp. 6147-6153 ◽  
Author(s):  
Anders Gabrielsson ◽  
Pavel Matousek ◽  
Michael Towrie ◽  
František Hartl ◽  
Stanislav Záliš ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Metal Complexes ◽  
Excited States ◽  
Decay Time ◽  
Ir Absorption ◽  
Time Resolved ◽  
Td Dft

Solvent Dependence of Structural Dynamics and Spin-flip Processes in 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (ortho-3CzBN)

2020 ◽  
Author(s):  
Masaki Saigo ◽  
Kiyoshi Miyata ◽  
Hajime Nakanotani ◽  
Chihaya Adachi ◽  
Ken Onda
Keyword(s):  
Dft Calculations ◽  
Excited States ◽  
Structural Changes ◽  
Photophysical Properties ◽  
Delayed Fluorescence ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Solvent Dependence ◽  
Acetonitrile Solutions

We have investigated the solvent-dependence of structural changes along with intersystem crossing of a thermally activated delayed fluorescence (TADF) molecule, 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (o-3CzBN), in toluene, tetrahydrofuran, and acetonitrile solutions using time-resolved infrared (TR-IR) spectroscopy and DFT calculations. We found that the geometries of the S1 and T1 states are very similar in all solvents though the photophysical properties mostly depend on the solvent. In addition, the time-dependent DFT calculations based on these geometries suggested that the thermally activated delayed fluorescence process of o-3CzBN is governed more by the higher-lying excited states than by the structural changes in the excited states.<br>

The Character of Low-Lying Excited States of Mixed-Ligand Metal Carbonyls. TD-DFT and CASSCF/CASPT2 Study of [W(CO)4L] (L = ethylenediamine, N,N'-dialkyl-1,4-diazabutadiene) and [W(CO)5L] (L = pyridine, 4-cyanopyridine)

2003 ◽  
Vol 68 (1) ◽  
pp. 89-104 ◽  
Author(s):  
Stanislav Záliš ◽  
Antonín Vlček ◽  
Chantal Daniel
Keyword(s):  
Excited States ◽  
Substitution Effect ◽  
Electronic Transitions ◽  
Ligand Field ◽  
Metal Carbonyls ◽  
Electron Density Redistribution ◽  
Time Resolved ◽  
Model Complex ◽  
Td Dft ◽  
Time Resolved Infrared Spectroscopy

This contribution presents the results of the TD-DFT and CASSCF/CASPT2 calculations on [W(CO)4(MeDAB)] (MeDAB = N,N'-dimethyl-1,4-diazabutadiene), [W(CO)4(en)] (en = ethylenediamine), [W(CO)5(py)] (py = pyridine) and [W(CO)5(CNpy)] (CNpy = 4-cyanopyridine) complexes. Contrary to the textbook interpretation, calculations on the model complex [W(CO)4(MeDAB)] and [W(CO)5(CNpy)] show that the lowest W→MeDAB and W→CNpy MLCT excited states are immediately followed in energy by several W→CO MLCT states, instead of ligand-field (LF) states. The lowest-lying excited states of [W(CO)4(en)] system were characterized as W(COeq)2→COax CT excitations, which involve a remarkable electron density redistribution between axial and equatorial CO ligands. [W(CO)5(py)] possesses closely-lying W→CO and W→py MLCT excited states. The calculated energies of these states are sensitive to the computational methodology used and can be easily influenced by a substitution effect. The calculated shifts of [W(CO)4(en)] stretching CO frequencies due to excitation are in agreement with picosecond time-resolved infrared spectroscopy experiments and confirm the occurrence of low-lying M→CO MLCT transitions. No LF electronic transitions were found for either of the complexes studied in the region up to 4 eV.

TD-DFT calculations of the excited states of metalloporphyrins relevant to organic solar photovoltaic cells

2014 ◽  
Vol 18 (06) ◽  
pp. 475-492 ◽  
Author(s):  
Neha Agnihotri ◽  
Ronald P. Steer
Keyword(s):  
Dft Calculations ◽  
Electronic State ◽  
Excited States ◽  
Photovoltaic Cells ◽  
Oscillator Strengths ◽  
Solar Photovoltaic ◽  
Dft Methods ◽  
Radiative Transitions ◽  
Td Dft ◽  
Triplet Excited States

The molecular orbital energies and symmetries, electronic state energies and symmetries, and orbital compositions and oscillator strengths for one-photon radiative transitions up to an energy of 4 eV have been calculated by DFT and TD-DFT methods for 15 d0 and d10 metalloporphyrins. Data for both singlet and triplet excited states are reported and used to identify potential candidates for use as photon upconverters by homomolecular triplet–triplet annihilation.

Synthesis and photophysical properties of extended π conjugated naphthalimides

2017 ◽  
Vol 16 (4) ◽  
pp. 539-546 ◽  
Author(s):  
C. Rémy ◽  
C. Allain ◽  
I. Leray
Keyword(s):  
Charge Transfer ◽  
Dft Calculations ◽  
Photophysical Properties ◽  
Photoinduced Charge Transfer ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Td Dft ◽  
Photoinduced Charge

A series of π conjugated naphthalimide derivatives were prepared. Compounds display efficient photoinduced charge transfer in solution which was rationalized by time-resolved spectroscopy and modelled by TD-DFT calculations.

Tuning Excited States of Bipyridyl Platinum(II) Chromophores with π-Bonded Catecholate Organometallic Ligands: Synthesis, Structures, TD-DFT Calculations, and Photophysical Properties

2014 ◽  
Vol 53 (13) ◽  
pp. 6624-6633 ◽  
Author(s):  
Jamal Moussa ◽  
Lise-Marie Chamoreau ◽  
Alessandra Degli Esposti ◽  
Maria Pia Gullo ◽  
Andrea Barbieri ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Excited States ◽  
Photophysical Properties ◽  
Td Dft

Ten-Nanosecond Step-Scan FT-IR Absorption Difference Time-Resolved Spectroscopy: Applications to Excited States of Transition Metal Complexes

1997 ◽  
Vol 51 (4) ◽  
pp. 580-583 ◽  
Author(s):  
Pingyun Chen ◽  
Richard A. Palmer
Keyword(s):  
Excited State ◽  
Excited States ◽  
Signal To Noise Ratio ◽  
Ir Absorption ◽  
Decay Kinetics ◽  
Time Resolved ◽  
Ligand Charge Transfer ◽  
Ft Ir ◽  
Good Signal ◽  
Nanosecond Time Resolution

Ten-nanosecond time resolution has been achieved with step-scan FT-IR absorbance difference spectroscopy (S2FT-IR Δ A TRS) and demonstrated by measuring Δ A spectra of fac-[Re(bpy)(CO)3Cl] and cis-[Os(bpy)2(CO)(4,4′-bpy)]2+ (bpy = 2,2′-bipyridine; 4,4′-bpy=4,4′-bipyridine) in CH3CN solution, following 355-nm laser excitation. In both complexes, the large shifts in (CO) to higher energy are consistent with the assignment that the lowest-energy excited states are metal-to-ligand charge transfer in nature. For [Os(bpy)2(CO)(4,4′-bpy)]2+, it is also possible to measure the excited-state decay kinetics, again with 10-ns resolution. In addition, Δ A bands are observed that are related to excited-state vibrations of the bipyridine ligands. Δ A spectra of good signal-to-noise ratio can be obtained for complexes with lifetimes as short as 10 ns.

Electronic excited states of chromium and vanadium bisarene complexes revisited: interpretation of the absorption spectra on the basis of TD DFT calculations

2014 ◽  
Vol 43 (47) ◽  
pp. 17703-17711 ◽  
Author(s):  
Sergey Ketkov ◽  
Nikolai Isachenkov ◽  
Elena Rychagova ◽  
Wen-Bih Tzeng
Keyword(s):  
Dft Calculations ◽  
Absorption Spectra ◽  
Excited States ◽  
Time Dependent ◽  
Electronic Excited States ◽  
Td Dft ◽  
Rydberg Transitions

The influence of the (η6-arene)2M (M = Cr, V, Cr+) composition on parameters of intravalency and Rydberg transitions is explained on the basis of time-dependent DFT.

Relative Stability of the La and Lb Excited States in Adenine and Guanine: Direct Evidence from TD-DFT Calculations of MCD Spectra

2014 ◽  
Vol 5 (11) ◽  
pp. 1806-1811 ◽  
Author(s):  
Fabrizio Santoro ◽  
Roberto Improta ◽  
Tobias Fahleson ◽  
Joanna Kauczor ◽  
Patrick Norman ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Excited States ◽  
Relative Stability ◽  
Direct Evidence ◽  
Td Dft

Solvent Dependence of Structural Dynamics and Spin-flip Processes in 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (ortho-3CzBN)

2020 ◽  
Author(s):  
Masaki Saigo ◽  
Kiyoshi Miyata ◽  
Hajime Nakanotani ◽  
Chihaya Adachi ◽  
Ken Onda
Keyword(s):  
Dft Calculations ◽  
Excited States ◽  
Structural Changes ◽  
Photophysical Properties ◽  
Delayed Fluorescence ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Solvent Dependence ◽  
Acetonitrile Solutions

We have investigated the solvent-dependence of structural changes along with intersystem crossing of a thermally activated delayed fluorescence (TADF) molecule, 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (o-3CzBN), in toluene, tetrahydrofuran, and acetonitrile solutions using time-resolved infrared (TR-IR) spectroscopy and DFT calculations. We found that the geometries of the S1 and T1 states are very similar in all solvents though the photophysical properties mostly depend on the solvent. In addition, the time-dependent DFT calculations based on these geometries suggested that the thermally activated delayed fluorescence process of o-3CzBN is governed more by the higher-lying excited states than by the structural changes in the excited states.<br>

Femtosecond spectroscopy and TD-DFT calculations of CuCl42− excited states

2014 ◽  
Vol 43 (47) ◽  
pp. 17820-17827 ◽  
Author(s):  
Elena N. Golubeva ◽  
Ekaterina M. Zubanova ◽  
Michail Ya. Melnikov ◽  
Fedor E. Gostev ◽  
Ivan V. Shelaev ◽  
...  
Keyword(s):  
Steady State ◽  
Dft Calculations ◽  
Excited States ◽  
Transient Absorption ◽  
Femtosecond Spectroscopy ◽  
Transient Absorption Spectroscopy ◽  
Femtosecond Transient Absorption ◽  
Td Dft ◽  
Femtosecond Transient Absorption Spectroscopy ◽  
Photoinduced Processes

Photoinduced processes of tetrahexylammonium tetrachlorocuprate [(C6H13)4N]2CuIICl4 in chloro-organic solvents were investigated by steady state photolysis and femtosecond transient absorption spectroscopy, as well as TD-DFT calculations of excited terms.

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