Tetraorganylborate salts as convenient precursors for photogeneration of tertiary amines

Sarker, Ananda M.; Lungu, Adrian; Mejiritski, Alexander; Kaneko, Yuji; Neckers, Douglas C.

doi:10.1039/a800469b

Cited by 22 publications

(19 citation statements)

References 22 publications

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“…Thus, no change of spin multiplicity may cause a high rate of Equation 5 as long as the systems remains in the singlet state. There must be found an [99][100][101][102][103][104][105][106][107][108][109][110][111][112][113][114], phenyl imino acetic acid 91 [115] or mercapto triazoles 92 [116]. The latter often exists in its tautomeric thione form.…”

Section: Polymer Synthesis Nir Sensitized Radical Photopolymerizationmentioning

confidence: 99%

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

Strehmel¹,

Schmitz²,

Kütahya³

et al. 2020

Beilstein J. Org. Chem.

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Cyanines derived from heptamethines were mainly discussed regarding their functionalization to broaden the solubility in different surroundings exhibiting either hydrophilic or hydrophobic properties and to tailor made the ΔG et photopysical properties with respect to absorption and fluorescence. Electrochemical properties were additionally considered for some selected examples. The cyanines chosen comprised as end groups either indolenine, benzo[e]- or benzo[cd]indolium pattern, which facilitated to shift the absorption between 750–1000 nm. This enabled their use in applications with light sources emitting in the near-infrared (NIR) region selected from high power LEDs or lasers with line-shaped focus. The absorbers considered were discussed regarding their function as sensitizer for applications related to Chemistry 4.0 standards. These were mainly photopolymer coatings, which can be found for applications in the graphic industry or to protect selected substrates. The huge release of heat on demand upon turning ON or OFF the NIR light source enables them for photothermal treatment in processes requesting heat to initiate either chemical (activated reactions) or physical (melting, evaporation) events.

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Section: Polymer Synthesis Nir Sensitized Radical Photopolymerizationmentioning

confidence: 99%

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

Strehmel¹,

Schmitz²,

Kütahya³

et al. 2020

Beilstein J. Org. Chem.

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“…However, many of these compounds showed limited solubility and stability in organic solvents, including poor thermal resistance . Furthermore, the photolysis efficiency showed to be generally dependent on the amine structure, which would be impractical in terms of versatility of amine incorporated into the QAs.…”

Section: Photobase Generatorsmentioning

confidence: 99%

Recent Advances and Challenges in the Design of Organic Photoacid and Photobase Generators for Polymerizations

et al. 2019

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Photopolymerization, or the use of light to trigger polymerization, is one of the most exciting technologies for advanced manufacturing of polymers. One of the key components in the photopolymerization processes is the photoactive compound that absorbs the light, generating the active species that promotes the polymerization and largely determines the final properties of the material. The field of photopolymerization has been dominated by photoradical generators to mediate radical reactions. In the last decade, to expand the number of polymers that can be prepared by photopolymerization, intensive research has been devoted to the synthesis and utilization of photoactive molecules that are able to generate a base or an acid upon irradiation. These organic compounds are known to promote not only the ring‐opening polymerization of various heterocyclic monomers such as lactones, carbonates, or epoxides but also to trigger the step‐growth synthesis of polyurethanes. This Minireview highlights the recent advances in the development of organic photobase and photoacid generators, with the aim of encouraging the wider application of these photoactive compounds in the photopolymerization area and to expand the use of these polymers in advanced manufacturing processes.

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“…First, ITX is an inexpensive, commercially available aryl ketone, known for its ability to mediate single electron‐transfer after photochemical excitation in the near UV/Vis region (350–420 nm); in particular, excited ITX is used as an electron acceptor sensitizer in many photoreactions . On the other hand, the tetraphenylborate anion may act as suitable electron donating partner to make PET thermodynamically feasible . Therefore, the expected primary photochemical process is electron‐transfer from BPh 4 − to triplet ITX.…”

Section: Introductionmentioning

confidence: 99%

“…[37] On the other hand, the tetraphenylborate anion may act as suitable electron donating partner to make PET thermodynamically feasible. [38,39] Therefore, the expected primary photochemical process is electron-transfer from BPh 4 À to triplet ITX. In second step, the resulting intermediate ITX radicala nion might effectively abstract proton from 1H + + (or 2H + + )t of orm NHC 1 (or 2).…”

Section: Introductionmentioning

confidence: 99%

Mixture of Azolium Tetraphenylborate with Isopropylthioxanthone: A New Class of N‐Heterocyclic Carbene (NHC) Photogenerator for Polyurethane, Polyester, and ROMP Polymers Synthesis

Trinh

Malval

Morlet‐Savary

et al. 2019

Chemistry A European J

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In the search of smarter routes to control the conditions of N‐heterocyclic carbene (NHCs) formation, a two‐component air‐stable NHC photogenerating system is reported. It relies on the irradiation at 365 nm of a mixture of 2‐isopropylthioxanthone (ITX) with 1,3‐bis(mesityl)imidazoli(ni)um tetraphenylborate. The photoinduced liberation of NHC is evidenced by reaction with a mesitoyl radical to form an NHC‐radical adduct detectable by electron spin resonance spectroscopy. The NHC yield can be determined by 1H NMR spectroscopy through the formation of a soluble and stable NHC–carbodiimide adduct. To deprotonate the azolium salt and liberate the NHC, a mechanism is proposed in which the role of base is played by ITX radical anion formed in situ by a primary photoinduced electron‐transfer reaction between electronically excited ITX (oxidant) and BPh4− (reductant). An NHC yield as high as 70 % is achieved upon starting with a stoichiometric ratio of ITX and azolium salt. Three different photoNHC‐mediated polymerizations are described: synthesis of polyurethane and polyester by organocatalyzed step‐growth polymerization and ring‐opening copolymerization, respectively, and generation of polynorbornene by ring‐opening metathesis polymerization using an NHC‐coordinated Ru catalyst formed in situ.

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Tetraorganylborate salts as convenient precursors for photogeneration of tertiary amines

Cited by 22 publications

References 22 publications

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

Recent Advances and Challenges in the Design of Organic Photoacid and Photobase Generators for Polymerizations

Mixture of Azolium Tetraphenylborate with Isopropylthioxanthone: A New Class of N‐Heterocyclic Carbene (NHC) Photogenerator for Polyurethane, Polyester, and ROMP Polymers Synthesis

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