Acyl phosphine oxides

When used in dental adhesive formulations, the water-soluble sodium 2,4,6-trimethylbenzoylphenyl phosphine oxide (APO-Na) [IKE 09] or the double-bond bearing derivative with improved solubility in polar solvents such as bis(3-((2-(allyloxy)ethoxy)methyl)-2,4,6-trimethylbenzoyl)(phenyl) phosphine oxide (WBAPO) [MOS 10] may be beneficial. 

Leaving CQ and acyl phosphine oxides, several other photoinitiators have been suggested for dental materials, from which only a few were considered for actual dental products. 

In 1988, effective titanate initiators were claimed for light and dual cured dental materials by Dentsply [WHI 89]. In particular, the initiator shown in 

Chapter written by Fr6d6ric Dumur and Didier Gigmes. 

Dyes and Chromophores in Polymer Science, First Edition. Edited by Jacques Lalevee and Jean-Pierre Fouassier. ISTE Ltd 2015. Published by ISTE Ltd and John Wiley Sons, Inc. 

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However, Ciba-Geigy has introduced (31,32) a type of phosphine-based photoinitiator. In general, the compound can be described as a bis(acyl)phosphine oxide and is prepared by the reaction of a monoaLkylphosphine with a substituted ben2oyl chloride (33). The composition of the first commercial product is proprietary. 

The acyl phosphonates, acyl phosphine oxides and related compounds (e.g. 81. 82) absorb strongly in the near UV (350-400 nm) and generally decompose by rescission in a manner analogous to the benzoin derivatives.381"285 Quantum yields vary from 0.3 to 1.0 depending on structure. The phosphinyl radicals are highly reactive towards unsaturated substrates and appear to have a high specificity for addition v.v abstraction (see 3.4.3.2). 

Phosphinyl radicals (e.g. 103-107) arc generated by photodecomposition of acyl phosphinates or acyl phosphine oxides (see 3.3.4.LI)282,466 474,473 or by hydrogen abstraction from the appropriate phosphine oxide.467... 

Alkyl ethers of benzoin Benzil dimethyl ketal 2-Hydroxy-2-methylphenol-l-propanone 2,2-Diethoxyacetophenone 2-Benzyl-2-At, V-dimethylamino- l-(4-morpholinophenyl) butanone Halogenated acetophenone derivatives Sulfonyl chlorides of aromatic compounds Acylphosphine oxides and bis-acyl phosphine oxides Benzimidazoles... 

Acylated phosphine oxides have been used as intermediates to unsaturated acids such as (276 Scheme 37). These compounds cannot be formed by the direct addition of an acid derivative of the phosphine oxide to a carbonyl (273). Instead, the ketophosphine oxide (274) is reduced and the lactones (275) are separated. The sequence is completed by treatment with KOH in aqueous THF followed elimination... 

Photoinitiators for Multiphotonic Absorption Multiphoton three-dimensional micro- and nanofabrication is an emerging technology where a laser beam activates the medium by a multiphoton excitation of the photoinitiator. Conventional one-photon UV sensitive cleavable photoinitiators such as bis-acyl phosphine oxides or benzoin ethers can be activated at 700-900 nm (which is thought to lead to the generation of the same usual initiating radicals) but their two-photon absorption cross sections are rather low. New developments are under way [106-111]. 

As photopol5merization initiators, an n-aminoketone, a a-hy-droxyketone, or a acyl phosphine oxide compound may be used. 

Photopolymerization initiators are alkylphenone-based photopolymerization initiators, acyl phosphine oxide-based photopolymer-... 

In acyl phosphine oxide-based photopolymerization initiators the chromophore structure after its photocleavage is highly different from that before the photocleavage, so the absorption spectrum largely changes to cause a decrease in absorption, which is known as photobleaching. Therefore, acyl phosphine oxide-based photo-pol merization initiators are preferred materials. 

Figure 4.4. Chemical structures of selected acyl phosphine oxide initiators 2,4,6-trimethylbenzoyldiphenyl phosphine oxide (TPO), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Ir-819), sodium 2,4,6-trimethylbenzcylphenyl phosphine oxide (APO-Na), A bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentyl phosphine oxide, B 1-hydroxycyclohexylphenylketone and A B = 1 3 (Ir-1800) and bis(3-((2-...

The electrochemical reduction of mono- and bis(acyl)phosphine oxides was observed to lead to the corresponding radical anions/ In the field of optically active phosphine oxides, the resolution of l-butyl-3-methyl-3-phospholene oxide with TADDOL derivatives was described/ The preparation of the enantiomers of BINAP and its derivatives was summarized in a review/ The deracemization of tert-butyl-phenylphosphine oxide using dibenzoyltartaric acid afforded one enantiomer in a configurationally stable form, in contrast to suggestions in the literature and to general opinion. The enantiomer of the secondary phosphine oxide was utilized in the preparation of a-hydroxyphosphine oxides (Scheme 64). The adducts were obtained in >95% ee and in >95% de. °... 

A bis(acyl)phosphine oxide, used as photoinitiator, was synthesized by the reaction of NaPH2(NaO Bu)x (x=2.4-2.8 generated from elemental phosphorus, sodium and tert-butanol) and 2,4,6-trimethylbenzoyl chloride (mesitoyl chloride) to give sodium bis(mesitoyl)phosphide as an intermediate that was converted to the target compound by alleviation with a functionalized allgvl halide followed by oxidation (Scheme 1). Trofimov prepared a mixture of tris(2-pyridyl)phosphine and its phosphine oxide by the reaction of red or white phosphorus in a superbasic KOH/DMSO/H2O suspension at 100/75 °C (Scheme 2). ... 

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