Properties of excited singlet states of N-arylurethanes

Schwetlick, K.; Stumpe, Joachim; Noack, Rainer

doi:10.1016/0040-4020(79)85009-7

Cited by 18 publications

(4 citation statements)

References 21 publications

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“…The triplet of triplets pattern is due to the hyperfine coupling with two unequivalent nitrogens with large coupling constants, 1.72 and 1.01 mT.6 When the electrolysis was stopped, this species decayed with half-lives of ~10 s at -33 °C and ~90 s at -83 °C. Similar spectra were observed for (p-MeOC6H4)2CN2 (2) and Ph(Me)-CN2 (3). Even when an -methyl group is attached, couplings of protons were too small to resolve (Figure lb).…”

supporting

confidence: 78%

ESR study on the .sigma.- and .pi.-radical cations formed by one-electron oxidation of phenyldiazomethanes

Ishiguro¹,

Sawaki²,

Izuoka³

et al. 1987

J. Am. Chem. Soc.

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supporting

confidence: 78%

ESR study on the .sigma.- and .pi.-radical cations formed by one-electron oxidation of phenyldiazomethanes

Ishiguro¹,

Sawaki²,

Izuoka³

et al. 1987

J. Am. Chem. Soc.

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“…For aromatic urethane unit, the proceeding of photo-Fries rearrangement is often observed [19][20][21][22]. Plausible photoreaction is seen as shown in Scheme 1, where resulting aromatic amino groups can react with unreacted isocyanato groups to form new covalent bonds.…”

Section: Photoreactions Of Ppasmentioning

confidence: 99%

Networked Polyphthalaldehydes Linked with Oxime Ether and Urethane Units and Their Photo-induced Depolymerization

Suyama,

Hayashi,

Tachi

2023

J. Photopol. Sci. Technol.

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Photo-induced depolymerization is a useful technique in designing functional materials and polymer recycling. Polyphthalaldehyde (PPA) has been known to be depolymerizable even in solid state. In this study, networked PPAs linked with oxime ether and urethane units have been prepared, and their photo-induced depolymerization was attempted. The networked structure of PPAs was prepared by anionic polymerization of phthalaldehyde monomer (o-PA) initiated with trifunctional oxime and 1,8-diazabicyclo[5.4.0]undec-7-ene to form truxene core bearing three PPA chains, followed by termination with difunctional isocyanates. We could obtain networked PPAs from 1,5-naphthalene diisocyanate, although could not from hexamethylene diisocyanate. Obtained networked polymers were pressed in neat pellets and UV-irradiated with Hg-Xe lamp (>310 nm). By repeated irradiation in solid state and dispersed state in chloroform, almost of the PPAs became soluble in chloroform. In 1 H NMR spectra of the soluble fractions, peaks due to o-PA and phthalide were observed, suggesting the proceeding of almost complete decrosslinking and depolymerization. Trace amount of insoluble powder finally remained and discussed based on its IR spectrum. We also compared the scanning microscope images of PPAs before and after irradiation.

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“…Therefore, to examine realistic polyurethane model systems, the new model compounds, bisphenol biscarbamates, were synthesized according to Equations (1)- (3). In addition, model diamine compounds corresponding to the degradation product of biscarbamates were also synthesized according to Equations (4)- (9).…”

Section: Photolysis Of Model Compounds In Dmfmentioning

confidence: 99%