Photodimerization of coumarin revisited: Effects of solvent polarity on the triplet reactivity and product pattern

Wolff, Thomas; Görner, Helmut

doi:10.1039/b312335a

Cited by 86 publications

(83 citation statements)

References 38 publications

(89 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The photochemistry of COU and its derivatives is rather complex because the quantum yield and distribution of products strongly depend both on the solvent [38] and the concentration of COU [39]. In principle, four stereoisomeric dimers are conceivable: syn Head-to-Head ( syn -HH), anti -HH, syn -Head-to-Tail ( syn -HT), and anti -HH, shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Topochemical control of the photodimerization of aromatic compounds by γ-cyclodextrin thioethers in aqueous solution

Wang

Wenz

2013

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

SummaryThe formation of soluble 1:2 complexes within hydrophilic γ-cyclodextrin (γ-CD) thioethers allows to perform photodimerizations of aromatic guests under controlled, homogenous reaction conditions. The quantum yields for unsubstituted anthracene, acenaphthylene, and coumarin complexed in these γ-CD thioethers were found to be up to 10 times higher than in the non-complexed state. The configuration of the photoproduct reflected the configuration of the dimeric inclusion complex of the guest. Anti-parallel orientation of acenaphthylene within the CD cavity led to the exclusive formation of the anti photo-dimer in quantitative yield. Parallel orientation of coumarin within the complex of a CD thioether led to the formation of the syn head-to-head dimer. The degree of complexation of coumarin could be increased by employing the salting out effect.

show abstract

Section: Resultsmentioning

confidence: 99%

Topochemical control of the photodimerization of aromatic compounds by γ-cyclodextrin thioethers in aqueous solution

Wang

Wenz

2013

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

show abstract

“…Recently we reported [4][5][6] that CB8 as low as 10 mol% acts as a supramolecular catalytic nano reaction vessel and facilitates the photodimerization of coumarins 7,8 in water leading to syn-dimers exclusively (Scheme 1). Saturation kinetics showed a sigmoidal dependence with a turnover number of 3.4 min…”

mentioning

confidence: 99%

“…Various research groups have established the superior molecular recognition properties of cucurbiturils (CBs). 3 We have been exploring the use of cucurbit [8]urils (CB8) to control the photoreactivity of coumarin derivatives. Additionally, we are interested in employing CB8 in catalytic amounts to carry out synthetic photochemical transformations to overcome a fundamental bottleneck viz., solubility of CB8 in higher amounts in water.…”

mentioning

confidence: 99%

“…The transient absorption centered around 420 nm was assigned to the triplet-triplet absorption of 1 based on similarities with previously published spectra. 8 Triplet absorption decay traces were recorded at different concentrations of CB8 (Fig. 1C).…”

mentioning

confidence: 99%

“…Fragmentation studies revealed that this signal corresponded to the CB8-photodimer complex.z Photodimerization of 1 was established to originate from the triplet state. 8 To understand the dynamics and triplet state reactivity of CB8-1 HG complex, laser flash photolysis studies were performed. Laser excitation (308 nm, pulse width: 15 ns) of deoxygenated aqueous solutions of CB8-1 HG complex (CB8 25 mM and 50 mM 1) generated a transient absorption spectrum (Fig.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Supramolecular photocatalysis: insights into cucurbit[8]uril catalyzed photodimerization of 6-methylcoumarin

et al. 2011

View full text Add to dashboard Cite

show abstract

Programmed Multiresponsive Hydrogel Assemblies with Light‐Tunable Mechanical Properties, Actuation, and Fluorescence

Lu¹,

Zhu²,

Wu³

et al. 2020

Adv Funct Materials

View full text Add to dashboard Cite

Fabrication strategies for programmed hydrogels that provide precise spatial control with predetermined responses to external stimuli are highly desirable. In this study, a partially reversible light‐driven assembly (PRLDA) method is introduced to construct multiresponsive hydrogels utilizing microgel (MG) particle building blocks (swollen diameter of 107 nm). No other material is required to prepare the gels beyond the MGs themselves. Facile preparation of multiresponsive hydrogels that are reversibly responsive to light, pH, and temperature using phototriggered covalent interlinking of coumarin‐based MGs is demonstrated. The gels have phototuneable moduli and swelling ratios and show light‐assisted healing and reshaping. Remarkably, the intrinsic fluorescence of the gels undergoes a reversible light‐triggered wavelength‐shift. The emission peak blueshifted from 420 to 390 nm upon irradiation with 365 nm light. The PRLDA gels can be constructed using either positive or negative photopatterning. It is shown that the gels can be exploited for multiresponsive cytocompatible actuators, grippers, and ON/OFF circuit components as well as anticounterfeit gels. The PRLDA method provides new insight into programmed gel property control and has excellent potential for biomaterial and optoelectronic applications.

show abstract

Photodimerization of coumarin revisited: Effects of solvent polarity on the triplet reactivity and product pattern

Cited by 86 publications

References 38 publications

Topochemical control of the photodimerization of aromatic compounds by γ-cyclodextrin thioethers in aqueous solution

Topochemical control of the photodimerization of aromatic compounds by γ-cyclodextrin thioethers in aqueous solution

Supramolecular photocatalysis: insights into cucurbit[8]uril catalyzed photodimerization of 6-methylcoumarin

Programmed Multiresponsive Hydrogel Assemblies with Light‐Tunable Mechanical Properties, Actuation, and Fluorescence

Contact Info

Product

Resources

About