Synchrotron ultrafast techniques for photoactive transition metal complexes

Borfecchia, Elisa; Garino, Claudio; Salassa, Luca; Lamberti, Carlo

doi:10.1098/rsta.2012.0132

Cited by 19 publications

(21 citation statements)

References 284 publications

(511 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The difference scattering signal arises from all structural dynamics induced by the laser pump pulse. In the standard analysis formalism222325, Δ S ( Q , t ) is described as the sum of difference scattering components arising from changes in the solute structure32, changes in the solvation cage structure33, and changes in the bulk solvent structure34.…”

Section: Resultsmentioning

confidence: 99%

“…Ultrafast X-ray diffuse scattering (XDS)192021222324 directly probes the time-dependent changes in the distribution of distances between all unique pairs of atoms2122252627, a property directly available from molecular dynamics simulations1322. This makes the comparison between experiment and simulation straight forward by avoiding the often complex conversion of simulation results to spectroscopic observables.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Atomistic characterization of the active-site solvation dynamics of a model photocatalyst

et al. 2016

View full text Add to dashboard Cite

The interactions between the reactive excited state of molecular photocatalysts and surrounding solvent dictate reaction mechanisms and pathways, but are not readily accessible to conventional optical spectroscopic techniques. Here we report an investigation of the structural and solvation dynamics following excitation of a model photocatalytic molecular system [Ir2(dimen)4]2+, where dimen is para-diisocyanomenthane. The time-dependent structural changes in this model photocatalyst, as well as the changes in the solvation shell structure, have been measured with ultrafast diffuse X-ray scattering and simulated with Born-Oppenheimer Molecular Dynamics. Both methods provide direct access to the solute–solvent pair distribution function, enabling the solvation dynamics around the catalytically active iridium sites to be robustly characterized. Our results provide evidence for the coordination of the iridium atoms by the acetonitrile solvent and demonstrate the viability of using diffuse X-ray scattering at free-electron laser sources for studying the dynamics of photocatalysis.

show abstract

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Atomistic characterization of the active-site solvation dynamics of a model photocatalyst

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The excited-state conformational change observed herein for G221 is reminiscent of the backbone twisting of 4-(N,N-dimethylamino)benzonitrile and its close derivatives and analogues, which are characteristic of the famed twisted intramolecular charge-transfer (TICT) excited state. [49][50][51][52] By use of extracted time constants (Table 2), kinetic traces at a set of wavelengths (see the Supporting Information, Figure S4 and S6) can be nicely fitted and difference spectra (see the Supporting Information, Figure S5 and S7) at a suit of time delays can be satisfactorily recreated. The exact torsional motions could be better clarified by means of time-resolved photoacoustic calorimetry, photothermal beam deflection, [48] and pulsed synchrotron X-ray analyses.…”

Section: Resultsmentioning

confidence: 99%

“…The exact torsional motions could be better clarified by means of time-resolved photoacoustic calorimetry, photothermal beam deflection, [48] and pulsed synchrotron X-ray analyses. [49][50][51][52] By use of extracted time constants (Table 2), kinetic traces at a set of wavelengths (see the Supporting Information, Figure S4 and S6) can be nicely fitted and difference spectra (see the Supporting Information, Figure S5 and S7) at a suit of time delays can be satisfactorily recreated. The kinetic traces of these key components, such as D* FC , D* LE , D* CT , and TiO 2 (e À )/D + are displayed in Figure 5 f and g (G221 and C264, respectively).…”

Section: Resultsmentioning

confidence: 99%

Electron‐Acceptor‐Dependent Light Absorption, Excited‐State Relaxation, and Charge Generation in Triphenylamine Dye‐Sensitized Solar Cells

Zhang

Yan

et al. 2014

ChemSusChem

View full text Add to dashboard Cite

By choosing a simple triphenylamine electron donor, we herein compare the influence of electron acceptors benzothiadiazole benzoic acid (BTBA) and cyanoacrylic acid (CA), on energy levels, light absorption, and dynamics of excited-state evolution and electron injection. DFT and time-dependent DFT calculations disclosed remarkable intramolecular conformational changes for the excited states of these two donor-acceptor dyes. Photoinduced dihedral angle variation occurs to the triphenylamine unit in the CA dye and backbone planarization happens to conjugated aromatic blocks in the BTBA dye. Femtosecond spectroscopic measurements suggested the crucial role of having a long excited-state lifetime in maintaining a high electron-injection yield because a reduced driving force for a low energy-gap dye can result in slower electron-injection dynamics.

show abstract

“…The nomenclature adopted for the edges recalls the atomic orbitals from which the electron is extracted, as shown in Figure 5.1a: K-edges are related to transitions from orbitals with the principal quantum number n = 1 (1s 1/2 ), L-edges refer to electron from the n = 2 orbitals (L I to 2s 1/2 , L II to 2p 1/2 , and L III to 2p 3/2 orbital), and so on for M, N, … edges. When the energy of the X-ray photon exceeds the ionization limit (case (i) mentioned above), the excited electron (generally named "photoelectron") has a kinetic energy E K given by E K = h ł − E B , where E B indicates the electron binding energy that is typical of the absorption edge (K, L I , L II or L III ) of the selected atomic species [13,34]. Once ejected, the photoelectron propagates thorough the sample as a spherical wave diffusing from the absorber atom, with a wave vector of modulus k defined by Eq.…”

Section: Theoretical Background Of Xas Spectroscopymentioning

confidence: 99%

5. Structural and electronic characterization of nanosized inorganic materials by X-ray absorption spectroscopies

Borfecchia¹,

Agostini²,

Bordiga³

et al. 2013

Inorganic Micro- And Nanomaterials

Self Cite

View full text Add to dashboard Cite

Starting from the late seventies, the progressively increased availability of synchrotron light sources has allowed the execution of experiments requiring a high X-ray flux in a continuous interval [1][2][3][4]. Among the various techniques developed, X-ray absorption spectroscopy (XAS, also known as X-ray absorption fine-structure, XAFS) [5][6][7][8][9][10][11][12][13] in both near (XANES) and post (EXAFS) edge regions, has become a powerful characterization technique widely employed in many research fields concerning inorganic chemistry, such as catalysis [13][14][15][16][17], organometallic and coordination complexes [18], metal nanoparticles [19, 20], electrochemical processes [21, 22], coordination polymers or metallorganic frameworks [23], bio-inorganic molecules including metalloproteins [24-27], chemistry of actinide elements [28], and solid state chemistry [12,[29][30][31].In this chapter, we will provide a brief introduction to the basic theory of XAS spectroscopy (Section 5.2), followed by selected examples having some didactic perspective (Sections 5.3-5.7). For the sake of brevity, only a fraction of the subjects mentioned above will be discussed; in particular, the chapter will deal with: the reactivity of the CuCl 2 /Al 2 O 3 -based catalysts for ethylene oxychlorination (Section 5.3); the structure, the electronic configuration and the reactivity of Cp 2 Cr molecules encapsulated in porous solids (Section 5.4); the structural characterization of metal complexes in solution (Section 5.5); the structural characterization of the UiO-66 and UiO-67 class of metallorganic frameworks (Section 5.6); and the determination of the local structure of an Alxw Gayw In 1−xw−yw As/Al xb Ga yb In 1−xb −yb As strained heterostructure grown on InP by metallorganic vapor phase epitaxy (Section 5.7) as an example of space-resolved EXAFS applied to a topic pertinent to solid state chemistry. XAS spectroscopy: Basic backgroundThe aim of this section is to provide the reader with a concise review of the basic physical principles on which the interpretation of EXAFS and XANES data is based. For a more detailed description of the theoretical background and the experimental aspects of XAS we refer to the extensive specialized literature (e.g., [5][6][7][8][9][10][11][12][13]).

show abstract

Synchrotron ultrafast techniques for photoactive transition metal complexes

Cited by 19 publications

References 284 publications

Atomistic characterization of the active-site solvation dynamics of a model photocatalyst

Atomistic characterization of the active-site solvation dynamics of a model photocatalyst

Electron‐Acceptor‐Dependent Light Absorption, Excited‐State Relaxation, and Charge Generation in Triphenylamine Dye‐Sensitized Solar Cells

5. Structural and electronic characterization of nanosized inorganic materials by X-ray absorption spectroscopies

Contact Info

Product

Resources

About