Application of XANES spectroscopy to study local structure of photoexcited Cu complex

Smolentsev, Grigory; Сухарина, Г. Б.; Soldatov, A. V.; Chen, Lin X.

doi:10.1016/s0168-9002(09)00773-6

Cited by 9 publications

(9 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Turning to the excited state, the present transient XAS spectrum exhibits more details than previously reported, 34,35 primarily because of our high-repetition-rate pump−probe data acquisition scheme. 36 In the pre-edge region, we observe a relatively weak positive feature at ∼8.977 keV, which corresponds to a transition into the hole, created by photoexcitation, in the HOMO.…”

Section: ■ Molecular Dynamics Simulationsmentioning

confidence: 79%

“…It is interesting to note that Chaboy et al 61 recently reported that these features in Cu(II) spectra are heavily influenced by multielectronic configurations and, in particular, are only correctly described only when two absorption channels are incorporated into the calculation. However, they used the MT approximation, which, as shown by Smolentsev et al,34,35 represents a significant approximation for this complex. We do not rule out multielectronic effects as a possible explanation for the deviation between the experiment and theory, but this is beyond the scope of the present work.…”

Section: ■ Molecular Dynamics Simulationsmentioning

confidence: 99%

See 1 more Smart Citation

Solvent-Induced Luminescence Quenching: Static and Time-Resolved X-Ray Absorption Spectroscopy of a Copper(I) Phenanthroline Complex

Penfold

Karlsson²,

Capano³

et al. 2013

J. Phys. Chem. A

117

151

View full text Add to dashboard Cite

We present a static and picosecond X-ray absorption study at the Cu K-edge of bis(2,9-dimethyl-1,10-phenanthroline)copper(I) ([Cu(dmp)2](+); dmp = 2,9-dimethyl-1,10-phenanthroline) dissolved in acetonitrile and dichloromethane. The steady-state photoluminescence spectra in dichloromethane and acetonitrile are also presented and show a shift to longer wavelengths for the latter, which points to a stronger stabilization of the excited complex. The fine structure features of the static and transient X-ray spectra allow an unambiguous assignment of the electronic and geometric structure of the molecule in both its ground and excited (3)MLCT states. Importantly, the transient spectra are remarkably similar for both solvents, and the spectral changes can be rationalized using the optimized ground- and excited-state structures of the complex. The proposed assignment of the lifetime shortening of the excited state in donor solvents (acetonitrile) to a metal-centered exciplex is not corroborated here. Molecular dynamics simulations confirm the lack of complexation; however, in both solvents the molecules come close to the metal but undergo rapid exchange with the bulk. The shortening of the lifetime of the title complex and nine additional related complexes can be rationalized by the decrease in the (3)MLCT energy. Deviations from this trend may be explained by means of the effects of the dihedral angle between the ligand planes, the solvent, and the (3)MLCT-(1)MLCT energy gap.

show abstract

Section: ■ Molecular Dynamics Simulationsmentioning

confidence: 79%

Section: ■ Molecular Dynamics Simulationsmentioning

confidence: 99%

Solvent-Induced Luminescence Quenching: Static and Time-Resolved X-Ray Absorption Spectroscopy of a Copper(I) Phenanthroline Complex

Penfold

Karlsson²,

Capano³

et al. 2013

J. Phys. Chem. A

117

151

View full text Add to dashboard Cite

show abstract

“…It makes it possible to obtain the threedimensional local atomic structure of porous materials such as zeolites 36 and various complex systems containing copper and other transition metal atoms. 37 In this study, DFT calculations were performed using the PBE exchange correlation potential.…”

Section: Experimental and Theoretical Methodsmentioning

confidence: 99%

“…A combination of XAFS spectroscopy and the modeling of the material’s local atomic structure by DFT or Molecular Dynamics (MD) is a powerful and promising approach. It makes it possible to obtain the three-dimensional local atomic structure of porous materials such as zeolites and various complex systems containing copper and other transition metal atoms . In this study, DFT calculations were performed using the PBE exchange correlation potential.…”

Section: Experimental and Theoretical Methodsmentioning

confidence: 99%

Atomic Structure of Cu Centers in Mordenite Formed by Interaction of Copper Chloride with H-MOR Zeolite and Temperature Treatment

et al. 2021

View full text Add to dashboard Cite

The effect of temperature on the formation of copper centers in Cu-mordenite (Cu-MOR), obtained by solid-state ion exchange between copper chloride and zeolite H-mordenite, was studied by combining Density Functional Theory (DFT) simulations of the local atomic structures of copper with the analysis of Cu K-edge XANES and EXAFS, measured “in situ” from room temperature to 400 °C. Cu K edge XANES and EXAFS spectra have a different level of sensitivity regarding the detection of the angular and radial distribution of atoms in the closest vicinity of copper. Based on this, a simultaneous theoretical description of XANES and Fourier transforms F(R) of EXAFS in the extended range of interatomic distances R (up to ∼6 Å) was used as an efficient filter for selecting suitable atomic models of copper species from the number of models given by DFT. It was revealed that, between RT and ∼200 °C, the local structure around copper in Cu-MOR did not change and was similar to that of bulk CuCl. By increasing the temperature to 300 °C and then to 400 °C, changes in both Cu K-edge XANES and EXAFS were observed, indicating the reconstruction of the local structure of copper. At 300 °C, copper-containing fragments, with a CuCl-like structure, decompose to form two different types of copper centers in the vicinity of the eight-member rings of the zeolite framework. The first type contains one copper atom, a monomer, coordinated to three O atoms of the framework as first neighbors and an O, an Al, and two Si atoms as the next neighbors. The second type contains two Cu atoms, which form a dimer, in which each Cu atom has two O atoms and one Cl atom as the first neighbors and one Al and two Si atoms as the next neighbors. At 400 °C, the Cu–Cu interaction in all the structural models, which describe the Cu K-edge XAS spectra, led to the assumption that the formation of dicopper centers dominated. Furthermore, the simultaneous description of both Cu XANES and EXAFS suggested the necessity of doing the structural analysis based on a single dicopper model of the Cu center and to also consider linear combinations of other such models. The suitable linear combination was found based on the three most plausible structural models of the Cu environment containing a Cu–Cl–Cu chain, in which each copper atom is characterized by a very similar pair radial distribution function of the neighboring atoms. However, the angular distributions of these neighboring atoms are different in all three Cu centers due to the difference in the nonequivalent crystallographic sites of the Al atoms, near which the Cu centers formed in the zeolite framework. In Cu-MOR at 400 °C another type of Cu center, containing a Cu–O–Cu dimer, can exist simultaneously with the above-mentioned Cu centers with Cu–Cl–Cu dimers.

show abstract

“…Рентгеновская спектроскопия поглощения в сочетании с методом теории функционала плотности (DFT) позволяет получать достаточно полную трехмерную картину локальной атомной структуры пористых материалов, к которым относятся цеолиты [12], кроме того, XAFS-методика является эффективным инструментом анализа структуры и для других сложных систем, содержащих как медные центры [13], так и атомы других переходных металлов [14]. В настоящей работе для цеолита Cu−MOR расчеты в рамках метода DFT выполнены с использованием обменного корреляционного потенциала PBE [15].…”

Section: теоретические метода и подходыunclassified

Локальная структура медных центров в цеолите Сu-морденит, образованных в процессе твердофазного синтеза

Прядченко¹,

Сухарина²,

Ермакова³

et al. 2021

Журнал Технической Физики

View full text Add to dashboard Cite

Изучено влияние температурных условий синтеза на структуру ближнего окружения атомов меди в цеолитах Cu-морденитах, полученных методом твердофазного ионного обмена. С помощью двух взаимодополняющих методов --- спектроскопии рентгеновского поглощения и теории функционала плотности --- определены модели локальной атомной структуры активных центров меди в цеолите Cu-морденит при температурах 300 и 400oC. Установлено, что при 300oС среди ближайших соседей атома меди нет других атомов меди (одноцентровая модель), тогда как при 400oC структура центра содержит не менее двух атомов меди, формирующих мостиковые структуры типа Cu-O-Cu. Определены структурные параметры Сu-O-связей. Ключевые слова: цеолиты, мордениты, спектроскопия рентгеновского поглощения, метод DFT.

show abstract

Application of XANES spectroscopy to study local structure of photoexcited Cu complex

Cited by 9 publications

References 10 publications

Solvent-Induced Luminescence Quenching: Static and Time-Resolved X-Ray Absorption Spectroscopy of a Copper(I) Phenanthroline Complex

Solvent-Induced Luminescence Quenching: Static and Time-Resolved X-Ray Absorption Spectroscopy of a Copper(I) Phenanthroline Complex

Atomic Structure of Cu Centers in Mordenite Formed by Interaction of Copper Chloride with H-MOR Zeolite and Temperature Treatment

Локальная структура медных центров в цеолите Сu-морденит, образованных в процессе твердофазного синтеза

Contact Info

Product

Resources

About