Transient resonance Raman spectroscopy of copper(II) complexes of meso-tetraphenylporphine and meso-tetraphenylchlorin

Paula, Julio C. de; Walters, Valerie A.; Cardozo, Kevin

doi:10.1021/j100013a004

Cited by 28 publications

(54 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This line broadening may be explained by the scattering from the excited CT state, as proposed in Refs. [9,10], and/or by vibrational heating and power-induced broadening effects, which are likely to take place at extremely high excitation powers.…”

Section: Resultsmentioning

confidence: 99%

“…In particular, a vacancy in the upper d(x2-y 2) orbital results in a bigger affinity of excited CuP for nitrogen (N)-and oxygen (O)-containing molecules from the environment, whose con- ' Corresponding author. sequence is a possible reversible binding of these molecules to the central copper ion as a fifth axial ligand [2][3][4][5][6][7][8][9][10]. It has recently been reported that the excited triplet (~, "rr *) state (T I) of the water-soluble cationic Cu(II) derivative of 5,10,15,20-tetrakis[4-N-methylpyridyl]porphyrin (Cu(TMpy-P4)) has a short lifetime of ca.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Intermolecular interaction of photoexcited Cu(TMpy-P4) with water studied by transient resonance Raman and picosecond absorption spectroscopies

Kruglik

Ermolenkov

Shvedko

et al. 1997

Chemical Physics Letters

View full text Add to dashboard Cite

A photoinduced complex between Cu(TMpy-P4) and water molecules, reversibly axially coordinated to the central metal, was observed in picosecond transient absorption and nanosecond resonance Raman experiments. This complex is rapidly created (z~ = 15 + 5 ps) in the excited triplet (~r, ~r * ) state of Cu-porphyrin, and the subsequent relaxation is proposed to proceed via two parallel pathways. One is fast and efficient (>/90% of molecules), and presumably involves a (ax, d) charge-transfer state. The second pathway is slow (z 2 >> 1 ns), has a low quantum yield (~< 10%) and involves the excited (d, d) state which is responsible for transient Raman features at = 1553 cm -I (u2*) and = 1347 cm -1 (u4*), and for low-intensity long-lived transient absorption features.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Intermolecular interaction of photoexcited Cu(TMpy-P4) with water studied by transient resonance Raman and picosecond absorption spectroscopies

Kruglik

Ermolenkov

Shvedko

et al. 1997

Chemical Physics Letters

View full text Add to dashboard Cite

show abstract

“…In nitrogen-containing Lewis base solvents, such as bzn, it is instead quenched within about a hundred of picoseconds. [30][31][32][33][34] Figure5b shows the kinetics at 465 nm, which can be fitted with a single-exponential decay lifetime of 396 ± 5 ps. The trends in lifetime reduction have been convincingly explained by solvent-dependant energetics of the CT states.…”

Section: P-c 60mentioning

confidence: 99%

“…However, the exact assignment remains partly tentative to date since the CT state is too short-lived to be unambiguously identified by transient resonant Raman spectroscopy. 30,34 In addition, various theoretical models do not concord yet in their predictions, either for its identity or for its energy position.…”

Section: P-c 60mentioning

confidence: 99%

“…For Cu II P, such CT states have usually eluded unambiguous assignment through optical and Raman spectroscopies. [27][28][29][30][31][32][33][34][35][36][37] Being element-specific and applicable to any state of matter, time-resolved X-ray absorption spectroscopy (TR-XAS) is a rapidly maturing technique capable of delivering unique information about the electronic and geometric structures of metastable photoexcited states with picosecond and femtosecond temporal resolution. [38][39][40][41][42][43][44][45][46] Recently, it has been applied as a complementary analytical tool to investigate the decay pathways in laser-excited MPs and the early steps of CO and NO ligation/deligation in hemelike porphyrins relevant for respiration.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Elucidating the Ultrafast Dynamics of Photoinduced Charge Separation in Metalloporphyrin-Fullerene Dyads Across the Electromagnetic Spectrum

et al. 2016

View full text Add to dashboard Cite

Metalloporphyrins are prominent building blocks in the synthetic toolbox of advanced photodriven molecular devices. When the central ion is paramagnetic, the relaxation pathways within the manifold of excited states are highly intricate so that unravelling the intramolecular energy and electron transfer processes is usually a very complex task. This fact is critically hampering the development of applications based on the enhanced coupling offered by the electronic exchange interaction. In this work, the dynamics of charge separation in a copper porphyrin-fullerene are studied with several complementary spectroscopic tools across the electromagnetic spectrum (from near infra-red to X-ray wavelengths), each of them providing specific diagnostics. Correlating the various rates clearly demonstrates that the lifetime of the photoinduced charge-separated state exceeds by about 10 fold that of the isolated photoexcited Cu II porphyrin. As revealed by the spectral modifications in the XANES region, this stabilization is accompanied by a transient change in covalency around the Cu II center, which is induced by an enhanced interaction with the C 60 moiety. This experimental finding is further confirmed by state-of-the art calculations using DFT and TD-DFT including dispersion effects that explain the electrostatic and structural origins of this interaction, as the Cu II P cation becomes ruffled and approaches closer to the fullerene in the charge-separated state. From a methodological point of view, these results exemplify the potential of multielectron excitation features in transient X-ray spectra as future diagnostics of sub-femtosecond electronic dynamics. From a practical point of view, this work is paving the way for elucidating out-ofequilibrium electron transfer events coupled to magnetic interaction processes on their intrinsic time-scales.

show abstract

Transient resonance Raman spectroscopic studies of some paramagnetic metalloporphyrins: effects of axial ligand on charge-transfer and photoreduction processes

Jeoung

Kim

Cho

2000

J. Raman Spectrosc.

View full text Add to dashboard Cite

The presence of odd electrons in d-orbitals of the central metal ions of these metalloporphyrins gives rise to a strong interaction with porphyrin p-electronic system, which affects the energy relaxation pathways of their photoexcited states. The formation and energy of porphyrin $ metal (p,d) or (d,p * ) charge-transfer (CT) and metal (d,d) states are sensitive to the solvents employed, especially to the axial ligation ability of the solvents. Based on the change in Raman wavenumbers induced by the structural change in the exciplex formation of photoexcited Cu II TPP with the solvents, two intermediate ( p,d) CT states below the 2 T/ 4 T (p,p * ) states are proposed, one being less affected by the ligating solvent (CT 1 ; Cu II porphyrins * ) and the other strongly influenced by a s-donor axial ligand [CT 2 ; Cu II porphyrins * (ligand)]. As for XCr III TPP (X = Cl or Br), the photodissociation of axial ligand halogen atoms was observed in benzene.On the other hand, in THF upon photoexcitation, the axial ligand halogen atoms were replaced by the solvent molecules to form the five-coordinate Cr III TPP(THF). A significant reduction in the lifetimes of photoexcited ClCr III TPP in THF was observed, which is probably due to the participation of the low-lying (p,d p ) CT state in the energy relaxation of the five-

show abstract

Transient resonance Raman spectroscopy of copper(II) complexes of meso-tetraphenylporphine and meso-tetraphenylchlorin

Cited by 28 publications

References 1 publication

Intermolecular interaction of photoexcited Cu(TMpy-P4) with water studied by transient resonance Raman and picosecond absorption spectroscopies

Intermolecular interaction of photoexcited Cu(TMpy-P4) with water studied by transient resonance Raman and picosecond absorption spectroscopies

Elucidating the Ultrafast Dynamics of Photoinduced Charge Separation in Metalloporphyrin-Fullerene Dyads Across the Electromagnetic Spectrum

Transient resonance Raman spectroscopic studies of some paramagnetic metalloporphyrins: effects of axial ligand on charge-transfer and photoreduction processes

Contact Info

Product

Resources

About