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Diaryliodonium Salts (diaryliodonium + salt)
Selected AbstractsRegiospecific Reductive Elimination from Diaryliodonium Salts,ANGEWANDTE CHEMIE, Issue 24 2010Bijia Wang Die sterische Out-of-Plane-Belastung durch einen Cyclophansubstituenten an Iod(III) destabilisiert den Übergangszustand der reduktiven Eliminierung aus Diaryliodoniumsalzen und wirkt so regiochemisch steuernd (als SECURE bezeichnet), wie Rechnungen und experimentelle Studien belegen. Dies sollte allgemein bei hochvalenten Hauptgruppen- und Übergangsmetallionen gelten. X=N3, OAc, PhO, CF3CH2O, SCN, PhS. [source] ChemInform Abstract: Arylation of Anilines: Formation of Diarylamines Using Diaryliodonium Salts.CHEMINFORM, Issue 11 2008Michael A. Carroll Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Synthesis of Unsymmetrical Diaryl Selenides from Arylselenium Complexes of Titanocene and Diaryliodonium Salts.CHEMINFORM, Issue 47 2001Xiang Huang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: The Electrosynthesis of Diaryliodonium Salts.CHEMINFORM, Issue 9 2001Martin J. Peacock Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Conformational Structure and Energetics of 2-Methylphenyl(2,-methoxyphenyl)iodonium Chloride: Evidence for Solution ClustersCHEMISTRY - A EUROPEAN JOURNAL, Issue 34 2010Dr. Yong-Sok Lee Abstract Diaryliodonium salts allow the efficient incorporation of cyclotron-produced [18F]fluoride ions into electron-rich and electron-deficient arenes to provide potential radiotracers for molecular imaging in vivo with positron emission tomography (PET). This process (ArI+Ar,+18F,,Ar18F+Ar,I) is still not well understood mechanistically. To better understand this and similar reactions, it would be valuable to understand the structures of diaryliodonium salts in organic media, where the reactions are typically conducted. In this endeavor, the X-ray structure of a representative iodonium salt, 2-methylphenyl(2,-methoxyphenyl)iodonium chloride (1), was determined. Our X-ray structure analysis showed 1 to have the conformational M,P dimer as the unit cell with hypervalent iodine as a stereogenic center in each conformer. With the ab initio replica path method we constructed the inversion path between the two enantiomers of 1, thereby revealing two additional pairs of enantiomers that are likely to undergo fast interconversion in solution. Also LC,MS of 1 showed the presence of dimeric and tetrameric anion-bridged clusters in weak organic solution. This observation is consistent with the energetics of 1, both as monomeric and dimeric forms in MeCN, calculated at the B3LYP/DGDZVP level. These evidences of the existence of dimeric and higher order clusters of 1 in solution are relevant to achieve a deeper general understanding of the mechanism and outcome of reactions of diaryliodonium salts in organic media with nucleophiles, such as the [18F]fluoride ion. [source] Evaluation of initiator systems for controlled and sequentially curable free-radical/cationic hybrid photopolymerizationsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2005Joe D. Oxman Abstract Free-radical/cationic hybrid photopolymerizations of acrylates and epoxides were initiated using a three-component initiator system comprised of camphorquinone as the photosensitizer, an amine as the electron donor, and a diaryliodonium salt. Thermodynamic considerations revealed that the oxidation potential of the electron donor must be less than 1.34 V relative to SCE for electron transfer with the photoexcited camphorquinone to take place. This electron transfer leads to the production of the active centers for the hybrid polymerization (two radicals and a cation). Further investigation revealed that only a subset of electron donors that meet the oxidation potential requirement resulted in polymerization of the epoxide monomer; therefore, a second requirement for the electron donor (pKb higher than 8) was established. Experiments performed using a combination of electron donors revealed that the onset of the hybrid system's cationic polymerization can be advanced or delayed by controlling the concentration and composition of the electron donor(s). These studies demonstrate that a single three-component initiator system can be used to initiate and chemically control the sequential curing properties of a free-radical/cationic hybrid photopolymerization and is a viable alternative to separate photoinitiators for each type of polymerization. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1747,1756, 2005 [source] The participation of the anion and alkyl substituent of diaryliodonium salts in photo-initiated cationic polymerization reactionsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 3 2006Chul Ho Park Abstract The photo-initiated cationic polymerization (PCP) of epoxides using diaryliodonium salt photoacid generators (PAGs) bearing alkyl groups and anions was investigated. The properties and reactivities of a series of iodonium salts containing various cations and anions were compared in the context of a PCP reaction. The products from the decomposition of the cations of these salts were analyzed using gas chromatography-mass spectrometry (GC-MS) spectra. The relationship between the molecular structure of the salts and their reaction mechanism in the PCP reaction was investigated. Based on the results of the investigation, it was concluded that the structures of the cations and anions of theiodonium salts affect the PCP reaction rate, which was controlled by the products from the diaryliodonium salts. As part of an additional investigation, the diaryliodonium salts-epoxide materials were applied to 254,nm-photo-patterning. Copyright © 2006 John Wiley & Sons, Ltd. [source] Silane reduction of onium saltsAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2010James V. Crivello Abstract Novel redox initiators for cationic polymerizations were developed consisting of an onium salt together with a SiH functional silane or siloxane. The reduction of the onium salt by the silane is catalyzed by noble metal complexes or certain transition metal compounds and takes place spontaneously at room temperature. The redox reaction of the onium salt with the silane results in the liberation of a strong Brønsted acid that can be subsequently used to initiate cationic polymerizations. Typical onium salts that have been employed in these redox initiator systems are diaryliodonium salts, triarylsulfonium salts and S,S -dialkyl- S -phenacylsulfonium salts. Studies of the effects of variations in the structures of the onium salt, the silane and the type of noble metal catalyst were carried out. In principle, the redox initiator systems are applicable to all types of cationically polymerizable monomers and oligomers, including the ring-opening polymerizations of such heterocyclic monomers as epoxides and oxetanes and, in addition, the polymerization of vinyl monomers such as vinyl ethers, N -vinylcarbazole and styrenic monomers. The use of these novel initiator systems for carrying out commercially attractive crosslinking polymerizations for coatings, composites and encapsulations is discussed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Conformational Structure and Energetics of 2-Methylphenyl(2,-methoxyphenyl)iodonium Chloride: Evidence for Solution ClustersCHEMISTRY - A EUROPEAN JOURNAL, Issue 34 2010Dr. Yong-Sok Lee Abstract Diaryliodonium salts allow the efficient incorporation of cyclotron-produced [18F]fluoride ions into electron-rich and electron-deficient arenes to provide potential radiotracers for molecular imaging in vivo with positron emission tomography (PET). This process (ArI+Ar,+18F,,Ar18F+Ar,I) is still not well understood mechanistically. To better understand this and similar reactions, it would be valuable to understand the structures of diaryliodonium salts in organic media, where the reactions are typically conducted. In this endeavor, the X-ray structure of a representative iodonium salt, 2-methylphenyl(2,-methoxyphenyl)iodonium chloride (1), was determined. Our X-ray structure analysis showed 1 to have the conformational M,P dimer as the unit cell with hypervalent iodine as a stereogenic center in each conformer. With the ab initio replica path method we constructed the inversion path between the two enantiomers of 1, thereby revealing two additional pairs of enantiomers that are likely to undergo fast interconversion in solution. Also LC,MS of 1 showed the presence of dimeric and tetrameric anion-bridged clusters in weak organic solution. This observation is consistent with the energetics of 1, both as monomeric and dimeric forms in MeCN, calculated at the B3LYP/DGDZVP level. These evidences of the existence of dimeric and higher order clusters of 1 in solution are relevant to achieve a deeper general understanding of the mechanism and outcome of reactions of diaryliodonium salts in organic media with nucleophiles, such as the [18F]fluoride ion. [source] | |||||||||||||