Triplet states from Azides

Kober, Helge

doi:10.1007/bfb0047765

Cited by 9 publications

(2 citation statements)

References 90 publications

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“…36,46 Nitrenes are capable of forming both singlet and triplet excited states, the latter of which can abstract hydrogen from polymer backbones and presumably cause chain scission or form adducts through recombination (see Figure S5). 20,47 The shorter-lived singlet nitrene may form adducts via an insertion mechanism, and scission is an unlikely outcome (see Figure S6). Notably, Jørgensen et al have shown via SEC analysis of thermally annealed blends of poly(ethylene) and a benzenedisulfonyl azide that the grafting efficiency per thermolyzed azide is 40− 60% with no chain scission.…”

Section: Macromoleculesmentioning

confidence: 99%

Modulating Solubility and Enhancing Reactivity of Photo-Cross-Linkable Poly(styrene sulfonyl azide-alt-maleic anhydride) Thin Films

Janes

Maher²,

Carroll

et al. 2015

Macromolecules

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To formalize our understanding of indiscriminate grafting chemistries as they pertain to cross-linkable polymers and emerging patterning technologies, we designed a new polymer, poly(styrene sulfonyl azide-alt-maleic anhydride) (PSSMA). By modulating its solubility, it can be deposited into smooth, ultrathin films atop polar and nonpolar polymers. Upon heating above 120 °C or exposure to UV light, highly reactive nitrene intermediates are generated from the azide groups which form covalent adducts and cross-link the PSSMA. Azide photolysis and polymer gelation were studied in the context of a statistical model to gain insight into the network outcomes of nitrenes in a polymer film. For every azide group converted to a nitrene in ambient atmosphere, it has an 11% likelihood of grafting to another chain and a 5% chance of causing a scission. These values can be increased over 3-fold by reducing the O 2 content by 85%. Alternatively, the effects of quenching by ground-state O 2 can be mitigated by adding Michler's ketone (MK) to the film. PSSMA/MK blend films possess a 39% (±13) likelihood for grafting and 29% (±10) for scission. The higher ratio of scission to grafting is a consequence of the sensitized azides producing triplet-state nitrenes, which favor hydrogen abstraction. These broadly generalizable considerations will be useful to others who wish to maximize light sensitivity in related polymer systems.

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Section: Macromoleculesmentioning

confidence: 99%

Modulating Solubility and Enhancing Reactivity of Photo-Cross-Linkable Poly(styrene sulfonyl azide-alt-maleic anhydride) Thin Films

Janes

Maher²,

Carroll

et al. 2015

Macromolecules

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“…With few exceptions, organic nitrenes possess a triplet ground state centered on an N atom, , making them potential analogs to the NV centers. Though the possibility of using nitrenes in quantum information science has been highlighted, their instability has prevented any significant experimental efforts in this direction.…”

Section: Introductionmentioning

confidence: 99%

Stable Room Temperature Nitrenes Created by Photolysis of Crystalline 4-Azido-2,3,5,6-tetrafluorobenzoic Acid

et al. 2023

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The structure, spectroscopy, and photochemistry of 4-azidobenzoic acid (4ABC) and its perfluorinated analog 4-azido-2,3,5,6-tetrafluorobenzoic acid (4F4ABC) are characterized in frozen glasses and crystals. Photolysis of the parent azides leads to the production of nitrenes and other spin species that are probed by electron paramagnetic resonance and optical spectroscopy. Shifts in the absorption spectra for both the parent azides and the nitrenes were well reproduced using density functional calculations. Photolysis generates ∼10× higher yield of the triplet nitrene relative to the quintet and radical side-products in 4F4ABC, while the opposite ratio is observed in 4ABC. An annealing step further suppressed the side-products in 4F4ABC, creating a solid where nitrenes were the dominant spin species. The nitrene in the 4F4ABC crystal has a 1/e lifetime of 20 days at room temperature in open air. This stability makes it possible to photopattern nitrene centers into a single crystal and characterize their photoluminescence. Multiple observations suggest that the remarkable stability in the 4F4ABC crystal is a consequence of crystal packing that traps N2 molecules adjacent to the nitrene. The ability to create stable, solid-state nitrene samples may provide a route to organic high-spin materials with potential applications in spintronics and quantum information science.

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Theory and Computation in the Study of Nitrenes and their Excited‐State Photoprecursors

Vyas

Winter

Hadad

2013

Nitrenes and Nitrenium Ions

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Triplet states from Azides

Cited by 9 publications

References 90 publications

Modulating Solubility and Enhancing Reactivity of Photo-Cross-Linkable Poly(styrene sulfonyl azide-alt-maleic anhydride) Thin Films

Modulating Solubility and Enhancing Reactivity of Photo-Cross-Linkable Poly(styrene sulfonyl azide-alt-maleic anhydride) Thin Films

Stable Room Temperature Nitrenes Created by Photolysis of Crystalline 4-Azido-2,3,5,6-tetrafluorobenzoic Acid

Theory and Computation in the Study of Nitrenes and their Excited‐State Photoprecursors

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