Time-resolved studies on the photoisomerization of a phenylene–silylene–vinylene type compound in its first singlet excited state

Burdziński, Gotard; Bayda, Malgorzata; Hug, Gordon L.; Majchrzak, Mariusz; Marciniec, Bogdan; Marciniak, Bronisław

doi:10.1016/j.jlumin.2010.10.031

Cited by 20 publications

(20 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Nanosecond laser flash photolysis was performed with a home‐built setup described previously, using Q‐switched Nd:YAG laser (Continuum Surelite II) equipped with OPO module to generate laser pulses at 475 nm with 2 mJ per shot energy.…”

Section: Methodsmentioning

confidence: 99%

Ultrafast Dynamics of the Transoid‐cis Isomer Formed in Photochromic Reaction from 3H‐Naphthopyran

et al. 2020

View full text Add to dashboard Cite

Recent efforts in designing new 3H‐naphthopyran derivatives have been focused on efficient coloration process with a short fading time of the colored transoid‐cis TC isomer. It is desirable to avoid photoisomerization of TC leading to transoid‐trans TT isomers in the photoreaction. Long lifetime of TT can hamper fast applications such as dynamic holographic materials and molecular actuators, the residual color is one of the serious issues for photochromic lenses. Herein we characterize the photophysical and photochemical channels of TC excited state deactivation competing with the unwanted TC→TT isomerization process. Transient absorption spectroscopy reveals a very short lifetime of the singlet excited TC (≈0.8 ps) and its deactivation channels as S1→S0 internal conversion (major), intersystem crossing S1→T1, pyran ring formation, photoenolization and TC→TT isomerization. Computations support the S1→S0 and T1→S0 channels as responsible for photostabilization of the TC form.

show abstract

Section: Methodsmentioning

confidence: 99%

Ultrafast Dynamics of the Transoid‐cis Isomer Formed in Photochromic Reaction from 3H‐Naphthopyran

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Kinetic traces were fitted using the Levenberg–Marquard algorithm. Some laser flash photolysis data were also recorded using another setup …”

Section: Methodsmentioning

confidence: 99%

“…Some laser flash photolysis data were also recorded using another setup. [34] ChemCatChem 2018, 10,849 -858 www.chemcatchem.org…”

Section: Photophysical and Electrochemical Characteristicsmentioning

confidence: 99%

Flavin Photocatalysts for Visible‐Light [2+2] Cycloadditions: Structure, Reactivity and Reaction Mechanism

et al. 2018

View full text Add to dashboard Cite

New photocatalysts from the flavin family were found to mediate the [2+2] photocycloaddition reaction. 3‐Butyl‐10‐methyl‐5‐deazaflavin (3 a) and 1‐butyl‐7,8‐dimethoxy‐3‐methylalloxazine (2 e), if irradiated by visible light, were shown to allow an efficient (Φ≈3–10 %) intramolecular cyclisation of various types of substrates including substituted styrene dienes and bis(aryl enones), considered as electron‐rich and electron‐poor substrates, respectively, without any additional reagent. The versatility of the procedure was demonstrated by the cyclisation of photosensitive cinnamyl (E)‐3‐iodoallyl ether. Structure–activity studies found alloxazine 2 e was more active than 7‐monosubstituted (R=Cl, Br and MeO) alloxazines. The introduction of chlorine and bromine atom on the deazaflavin skeleton did not enhance the catalytic efficiency of 3 a. A detailed electrochemical and spectroscopic study explains the reaction mechanism proceeding through energy transfer from the flavin excited triplet state to the diene followed by its cyclisation.

show abstract

“…The transient absorption measurement system was constructed as described previously (Burdzinski et al 2011 ). Briefly, pump pulses (532 nm; 8 ns FWHM) were generated at a repetition rate of 0.5 Hz by a Q-switched Nd:YAG laser (Continuum Surelite II).…”

Section: Methodsmentioning

confidence: 99%

Bacteriopheophytin triplet state in Rhodobacter sphaeroides reaction centers

et al. 2016

View full text Add to dashboard Cite

It is well established that photoexcitation of Rhodobacter sphaeroides reaction centers (RC) with reduced quinone acceptors results in the formation of a triplet state localized on the primary electron donor P with a significant yield. The energy of this long-lived and therefore potentially damaging excited state is then efficiently quenched by energy transfer to the RC spheroidenone carotenoid, with its subsequent decay to the ground state by intersystem crossing. In this contribution, we present a detailed transient absorption study of triplet states in a set of mutated RCs characterized by different efficiencies of triplet formation that correlate with lifetimes of the initial charge-separated state P+HA−. On a microsecond time scale, two types of triplet state were detected: in addition to the well-known spheroidenone triplet state with a lifetime of ~4 μs, in some RCs we discovered a bacteriopheophytin triplet state with a lifetime of ~40 μs. As expected, the yield of the carotenoid triplet increased approximately linearly with the lifetime of P+HA−, reaching the value of 42 % for one of the mutants. However, surprisingly, the yield of the bacteriopheophytin triplet was the highest in RCs with the shortest P+HA− lifetime and the smallest yield of carotenoid triplet. For these the estimated yield of bacteriopheophytin triplet was comparable with the yield of the carotenoid triplet, reaching a value of ~7 %. Possible mechanisms of formation of the bacteriopheophytin triplet state are discussed.

show abstract

Time-resolved studies on the photoisomerization of a phenylene–silylene–vinylene type compound in its first singlet excited state

Cited by 20 publications

References 28 publications

Ultrafast Dynamics of the Transoid‐cis Isomer Formed in Photochromic Reaction from 3H‐Naphthopyran

Ultrafast Dynamics of the Transoid‐cis Isomer Formed in Photochromic Reaction from 3H‐Naphthopyran

Flavin Photocatalysts for Visible‐Light [2+2] Cycloadditions: Structure, Reactivity and Reaction Mechanism

Bacteriopheophytin triplet state in Rhodobacter sphaeroides reaction centers

Contact Info

Product

Resources

About