Ultrafast transient lens spectroscopy of photoisomerization dynamics of azocompounds in confined nanospace of cyclodextrins

Yui, Hiroharu; Takei, Masako; Hirose, Yasushi; Sawada, Tsuguo

doi:10.1063/1.1524044

Cited by 19 publications

(32 citation statements)

References 15 publications

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“…The longest component is absent in the used neat solvents. As described in the introduction, a previous report using fs-ultrafast transient lens technique gave times of 13, 28, and 140 ps for water, ␤-, and ␥-CD solutions, respectively (36). Therefore, the shortest ps-times observed with our ps-setup are reliable.…”

Section: Resultssupporting

confidence: 48%

“…Our mechanism for OII photodynamics in solution and the nanocavities is different from that previously proposed (36). It involves the coexistence of three structures: two tautomers and one rotamer.…”

Section: Femtochemistry In Solutioncontrasting

confidence: 40%

“…Secondly, because the presence of 15 mM 7-or 14-MA does not alter the fs and ps transients of OII in water, we explain the effect of CD in terms of restriction in motion of the -N-Nphenyl part of trans-HYZ tautomer. The restriction is due to the cavity size of the host and not the involvement of H-bonding interactions between the guest and the host, as suggested by a previous report (36). Indeed, in that work, the full dynamics was explained in terms of trans-cis isomerization in the AZO structure, and the possibility of proton transfer reaction was not examined.…”

Section: Femtochemistry In Solutionmentioning

confidence: 81%

“…So far, the CD inclusion complex studies have considered that OII in water solutions exists under AZO tautomer, contrary to many studies in solutions where OII coexists under AZO and HYZ forms (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Recently, ultrafast transient lens technique with a response function of Ϸ300 fs has been used to study the dynamics of OII in CD (36). The slowing of the longest component in CD (13 ps in water, 28 ps in ␤-CD, and 140 ps in ␥-CD solutions) observed in the ultrafast transient lens signal was explained in terms of restriction to trans-cis isomerization of AZO tautomer due to H-bond formation between CD and the guest (36).…”

mentioning

confidence: 99%

“…Recently, ultrafast transient lens technique with a response function of Ϸ300 fs has been used to study the dynamics of OII in CD (36). The slowing of the longest component in CD (13 ps in water, 28 ps in ␤-CD, and 140 ps in ␥-CD solutions) observed in the ultrafast transient lens signal was explained in terms of restriction to trans-cis isomerization of AZO tautomer due to H-bond formation between CD and the guest (36). The used ultrafast transient lens technique is sensitive to the molecular configuration changes induced by light and reflected in the refractive index of the solution-thermal lens effect at both ground and excited states (36,37).…”

mentioning

confidence: 99%

See 4 more Smart Citations

Femtochemistry of orange II in solution and in chemical and biological nanocavities

Douhal

Sanz

Tormo

2005

Proc. Natl. Acad. Sci. U.S.A.

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In this work, we report on studies of the nature of the dynamics and hydrophobic binding in cyclodextrins and human serum albumin protein complexes with orange II. With femtosecond time resolution, we examined the proton-transfer and trans-cis isomerization reactions of the ligand in these nanocavities and in pure solvents. Because of confinement at the ground state, the orientational motion in the formed phototautomer is restricted, leading to a rich dynamics. Therefore, the emission lifetimes span a large window of tens to hundreds of picoseconds in the cavities. Possible H-bond interactions between the guest and cyclodextrin do not affect the caged dynamics. For the protein-ligand complexes, slow diffusional motion (Ϸ630 ps) observed in the anisotropy decay indicates that the binding structure is not completely rigid, and the embedded guest is not frozen with the hydrophobic pocket. The ultrafast isomerization and decays are explained in terms of coupling motions between N-N and C-N stretching modes of the formed tautomer. We discuss the role of confinement on the trans-cis isomerization with the cavities and its relationships to frequency and time domains of nanostructure emission.cyclodextrins ͉ protein ͉ H-bond ͉ twisting ͉ anisotropy F emtosecond (fs) studies of caged molecules in nanocavities provide direct information on the relationship between time and space domains of molecular relaxation (1). Therefore, simple and complex (in concept) molecular systems have been studied using cyclodextrins (CDs), proteins, micelles, pores, and zeolites as nanohosts, demonstrating the confinement effect of the hydrophobic nanocavities on the spectroscopy and dynamics of the guests (2-13). Relevant information on the ultrafast dynamics of caged wavepackets involving breaking͞making chemical bonds, and solvation has been acquired.Orange II (OII) (Fig. 1), also called acid orange 7, is a molecule that has O-H . . . N and NAN bonds and may show photoinduced intramolecular proton-transfer (IPT) and transcis isomerization reactions. It is widely used in the dyeing of textiles, food, and cosmetics and thus is found in the wastewaters of the related industries (14). It has been reported that it exists under azoenol (AZO) and ketohydrazone (HYZ) forms (Fig. 1) (15-20). In a water solution, for example, the H-atom within the O-H . . . N intramolecular H-bond is shifted to the nitrogen site, making HYZ structure the most stable one (Ϸ95%) (20). In DMSO, the HYZ population decreases to 70%, and in solid state it becomes the only populated structure (20). Recent x-ray studies of phenyl substituted 1-(arylazo)-2-naphthols showed that this kind of molecules displaying HYZ-AZO tautomerism can form intramolecular resonance-assisted H-bonds from pure N-H . . . O to pure N . . . H-O structures, depending on the phenyl derivative (21, 22). Furthermore, a recent photophysical study of similar molecules in solution has shown the occurrence of a photoinduced proton-transfer reaction in AZO to give HYZ structure with a very low emission qu...

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Section: Resultssupporting

confidence: 48%

Section: Femtochemistry In Solutioncontrasting

confidence: 40%

Section: Femtochemistry In Solutionmentioning

confidence: 81%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Femtochemistry of orange II in solution and in chemical and biological nanocavities

Douhal

Sanz

Tormo

2005

Proc. Natl. Acad. Sci. U.S.A.

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Intra‐ and Intermolecular Proton Transfer and Related Processes in Confined Cyclodextrin Nanostructures

Douhal

2006

Hydrogen‐Transfer Reactions

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Computational Photochemistry of the Azobenzene Scaffold of Sudan I and Orange II Dyes: Excited‐State Proton Transfer and Deactivation via Conical Intersections

2015

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We employed the complete active space self-consistent field (CASSCF) and its multistate second-order perturbation (MS-CASPT2) methods to explore the photochemical mechanism of 2-hydroxyazobenzene, the molecular scaffold of Sudan I and Orange II dyes. It was found that the excited-state intramolecular proton transfer (ESIPT) along the bright diabatic (1) ππ* state is barrierless and ultrafast. Along this diabatic (1) ππ* relaxation path, the system can jump to the dark (1) nπ* state via the (1) ππ*/(1) nπ* crossing point. However, ESIPT in this dark state is largely inhibited owing to a sizeable barrier. We also found two deactivation channels that decay (1) ππ* keto and (1) nπ* enol species to the ground state via two energetically accessible S1 /S0 conical intersections. Finally, we encountered an interesting phenomenon in the excited-state hydrogen-bonding strength: it is reinforced in the (1) ππ* state, whereas it is reduced in the (1) nπ* state. The present work sets the stage for understanding the photophysics and photochemistry of Sudan I-IV, Orange II, Ponceau 2R, Ponceau 4R, and azo violet.

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Ultrafast transient lens spectroscopy of photoisomerization dynamics of azocompounds in confined nanospace of cyclodextrins

Cited by 19 publications

References 15 publications

Femtochemistry of orange II in solution and in chemical and biological nanocavities

Femtochemistry of orange II in solution and in chemical and biological nanocavities

Intra‐ and Intermolecular Proton Transfer and Related Processes in Confined Cyclodextrin Nanostructures

Computational Photochemistry of the Azobenzene Scaffold of Sudan I and Orange II Dyes: Excited‐State Proton Transfer and Deactivation via Conical Intersections

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