Intersystem crossing in Fe(II) coordination compounds

Hauser, Andreas; Adler, Peter; Deisenroth, S.; Gütlich, Philipp; Hennen, C.; Spiering, H.; Vef, Andreas

doi:10.1007/bf02069119

Cited by 15 publications

(9 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…19,26 Notably, we observe a stable k 2 from 4 K to 40 K, 26 and an exponential increase above 40 K. We find E a = 32 ± 17 meV, compared to 61 ± 9 meV for the LIESST-excited relaxation in the litterature. 19 Similarly, the relaxation rate is controlled mostly by the preexponential factor, as A = 6.4 for our results compared to A = 57 in Ref.…”

Section: Discussionmentioning

confidence: 74%

“…26 Experimental values of k 2 resulting from LIESST determined by Lee et al 19 are plotted in Fig. 4(a) alongside our results for comparison.…”

Section: Discussionmentioning

confidence: 96%

“…In turn, the HS state relaxes slowly to the LS state through intersystem crossing (ISC). 4,26 When fitting a given experimental spectrum with reference HS and LS spectra so as to extract the HS proportion, we do not notice any anomalous deviation from the noise present in the remainder spectrum. This suggests that a possible excited transitional state relaxes at least within the 60 s duration of our XAS spectrum.…”

Section: Discussionmentioning

confidence: 97%

See 2 more Smart Citations

First glimpse of the soft x-ray induced excited spin-state trapping effect dynamics on spin cross-over molecules

Davesne

Gruber

Miyamachi

et al. 2013

The Journal of Chemical Physics

View full text Add to dashboard Cite

The dynamics of the soft x-ray induced excited spin state trapping (SOXIESST) effect of Fe(phen)2(NCS)2 (Fe-phen) powder have been investigated by x-ray absorption spectroscopy (XAS) using the total electron yield method, in a wide temperature range. The low-spin (LS) state is excited into the metastable high-spin (HS) state at a rate that depends on the intensity of the x-ray illumination it receives, and both the temperature and the intensity of the x-ray illumination will affect the maximum HS proportion that is reached. We find that the SOXIESST HS spin state transforms back to the LS state at a rate that is similar to that found for the light induced excited spin state trapping (LIESST) effect. We show that it is possible to use the SOXIESST effect in combination with the LIESST effect to investigate the influence of cooperative behavior on the dynamics of both effects. To investigate the impact of molecular cooperativity, we compare our results on Fe-phen with those obtained for Fe{[Me2Pyrz]3BH}2 (Fe-pyrz) powder, which exhibits a similar thermal transition temperature but with a hysteresis. We find that, while the time constant of the dynamic is identical for both molecules, the SOXIESST effect is less efficient at exciting the HS state in Fe-pyrz than in Fe-phen.

show abstract

Section: Discussionmentioning

confidence: 74%

“…26 Experimental values of k 2 resulting from LIESST determined by Lee et al 19 are plotted in Fig. 4(a) alongside our results for comparison.…”

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 97%

See 1 more Smart Citation

First glimpse of the soft x-ray induced excited spin-state trapping effect dynamics on spin cross-over molecules

Davesne

Gruber

Miyamachi

et al. 2013

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…For [Fe(6-mepy) 3 tren](PF 6 ) 2 , (6-mepy) 3 20 In the diluted mixed crystal [Zn 1−x Fe x (6-mepy) 3 tren](PF 6 ) 2 (x = 0.0005), laser flash photolysis experiments showed the HS → LS relaxation to be a thermally activated process at temperatures above 100 K in accordance with the above. 21,22 Below 100 K, however, there is strong deviation from classical behavior towards a temperatureindependent quantum-mechanical tunneling process at 10 K with a relaxation rate constant of 10 −1 sec −1 . 21 Due to the large volume change, V HL , [Fe(6-mepy) 3 tren](PF 6 ) 2 and diluted [Zn 1−x Fe x (6-mepy) 3 tren](PF 6 ) 2 are particularly interesting with respect to their thermal spin transition as well as the HS → LS relaxation behavior.…”

Section: Introductionmentioning

confidence: 99%

Determination of the molecular structure of the short-lived light-induced high-spin state in the spin-crossover compound [Fe(6-mepy)3tren](PF6)
Chakraborty
¹
,
Tissot
²
,
Peterhans
³

et al. 2013
Phys. Rev. B
Self Cite
12
2
11
2
View full text Add to dashboard Cite

In the spin-crossover compound 3 tren](PF 6 ) 2 , (6-mepy) 3 tren = tris{4-[(6-methyl)-2-pyridyl]-3-aza-butenyl}amine, the high-spin state can be populated as a metastable state below the thermal transition temperature via irradiation into the metal to the ligand charge-transfer absorption band of the low-spin species. At 10 K, the lifetime of this metastable state is only 1 s. Despite this, it is possible to determine an accurate excited state structure by following the evolution of relevant structural parameters by synchrotron x-ray diffraction under continuous irradiation with increasing intensity. The difference in metal-ligand bond length between the high-spin and the low-spin states is found to be 0.192Å, obtained from an analysis of the experimental data using the mean-field approximation to model cooperative effects.

show abstract

“…Following this discovery, Decurtins et al [4] showed that at cryogenic temperatures, the HS/LS relaxation slows down such that under continuous irradiation, the iron(II) spin-crossover systems can be trapped in the HS state, for which the expression "light-induced excited state spin trapping (LIESST)" was coined. The discovery of LIESST triggered several years of intense research not only with regard to the mechanism of trapping in the HS state of the system but also to the chemical and physical parameters governing the lifetimes of the low-temperature metastable HS states [5][6][7][8][9][10][11][12][13]. The fact that LIESST can be observed in crystalline solids raised the interest for the study of cooperative effects.…”

Section: Introductionmentioning

confidence: 99%

Light-induced spin crossover in Fe(II)-based complexes: The full photocycle unraveled by ultrafast optical and X-ray spectroscopies

Cannizzo

Milne

Consani

et al. 2010

Coordination Chemistry Reviews

266

278

View full text Add to dashboard Cite

The light-induced ultrafast spin and structure changes upon excitation of the singlet metal-toligand-charge-transfer (1 MLCT) state of Fe(II)-polypyridine complexes are investigated in detail in the case of aqueous iron(II)-tris-bipyridine ([Fe II (bpy) 3 ] 2+) by a combination of ultrafast optical and X-ray spectroscopies. Polychromatic femtosecond fluorescence upconversion, transient absorption studies in the 290-600 nm region and femtosecond X-ray absorption spectroscopy allow us to retrieve the entire photocycle upon excitation of the 1 MLCT state from the singlet low spin ground state (1 GS) as the following sequence: 1,3 MLCT→ 5 T→ 1 GS, which does not involve intermediate singlet and triplet ligand field states. The population time of the HS state is found to be~150 fs, leaving it in a vibrationally hot state that relaxes in 2-3 ps, before decaying to the ground state in 650 ps. We also determine the structure of the high-spin quintet excited state by picosecond X-ray absorption spectroscopy at the K edge of Fe. We argue that given the many common electronic (ordering of electronic states) and structural (Fe-N bond elongation in the high spin state, Fe-N mode frequencies, etc.) similarities between all Fe(II)-polypyridine complexes, the results on the electronic relaxation processes reported in the case of [Fe II (bpy) 3 ] 2+ are of general validity to the entire family of Fe(II)-polypyridine complexes.

show abstract

Intersystem crossing in Fe(II) coordination compounds

Cited by 15 publications

References 31 publications

First glimpse of the soft x-ray induced excited spin-state trapping effect dynamics on spin cross-over molecules

First glimpse of the soft x-ray induced excited spin-state trapping effect dynamics on spin cross-over molecules

Determination of the molecular structure of the short-lived light-induced high-spin state in the spin-crossover compound [Fe(6-mepy)3tren](PF6)
Chakraborty
¹
,
Tissot
²
,
Peterhans
³

et al. 2013
Phys. Rev. B
Self Cite
12
2
11
2
View full text Add to dashboard Cite

Light-induced spin crossover in Fe(II)-based complexes: The full photocycle unraveled by ultrafast optical and X-ray spectroscopies

Contact Info

Product

Resources

About

Intersystem crossing in Fe(II) coordination compounds

Cited by 15 publications

References 31 publications

First glimpse of the soft x-ray induced excited spin-state trapping effect dynamics on spin cross-over molecules

First glimpse of the soft x-ray induced excited spin-state trapping effect dynamics on spin cross-over molecules

Determination of the molecular structure of the short-lived light-induced high-spin state in the spin-crossover compound [Fe(6-mepy)3tren](PF6)Chakraborty1, Tissot2, Peterhans3 et al. 2013Phys. Rev. BSelf Cite122112View full textAdd to dashboardCite

Light-induced spin crossover in Fe(II)-based complexes: The full photocycle unraveled by ultrafast optical and X-ray spectroscopies

Contact Info

Product

Resources

About

Determination of the molecular structure of the short-lived light-induced high-spin state in the spin-crossover compound [Fe(6-mepy)3tren](PF6)
Chakraborty
¹
,
Tissot
²
,
Peterhans
³

et al. 2013
Phys. Rev. B
Self Cite
12
2
11
2
View full text Add to dashboard Cite