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Joseph S Merola - One of the best experts on this subject based on the ideXlab platform.
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alkyne reactions with Trimethylphosphine complexes of iridium lessons for the catalysis of vinyl ester formation and alkyne dimerization
Polyhedron, 2014Co-Authors: Joseph S Merola, Folami T LadipoAbstract:Abstract The combination of iridium with Trimethylphosphine ligands yields very electron rich iridium compounds that are active for terminal alkyne dimerization chemistry as well as the addition of carboxylic acids to alkynes. The structures, catalytic and stoichiometric chemistry of some iridium tris-trimethlyphosphine compounds with benzoate ligands are detailed in this paper. The roles that these compounds may play in the catalytic cycles involved in the dimerization of terminal alkynes and the addition of benzoic acid to terminal alkynes are examined and possible mechanisms for these catalytic reactions are proposed.
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synthesis reactivity and crystal structures of various solvates of fac tris Trimethylphosphine trichloroiridium
Polyhedron, 2013Co-Authors: Joseph S Merola, Marion A Franks, Joy F FrazierAbstract:The synthesis of fac-tris(Trimethylphosphine)iridiumtrichloride is reported and the crystal structure of five different solvates of this compound are analyzed. Compared with the idealized structure calculated with DFT methods, bond angles and distances differ considerably for all of the solvates examined. The utility of fac-tris(Trimethylphosphine)iridiumtrichloride for the synthesis of organometallic compounds of iridium(III) is also demonstrated.
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the basicity of tris Trimethylphosphine cyclooctadiene iridium i
Journal of Organometallic Chemistry, 2013Co-Authors: Joseph S Merola, Marion A FranksAbstract:[Tris-(Trimethylphosphine)(cyclooctadiene)iridium(I)]chloride, [Ir(COD)(PMe3)3]Cl, is very electron rich. In this report, that electron rich character is probed by examining the protonation of the complex at the metal center to form the dicationic [tris-(Trimethylphosphine)(cyclooctadiene)(hydrido)iridium(III)], [HIr(COD)(PMe3)3] þ2 . The exact formulation of the species formed depends on the nature of the Bronsted acid’s counterion. Protonation with hydrogen chloride, fluoroboric acid, and triflic acid are all described and the structure of the dication and some products from further reaction of the dication are elucidated. Simple aqueous acid/base titration of [Ir(COD)(PMe3)3]Cl is described yielding a pKa for [HIr(COD) (PMe3)3] þ2 of 4.2.
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Addition of carbanions to tris(Trimethylphosphine)(cyclooctadiene)iridium(I) chloride: three different modes of reaction depending on the nature of the carbanion
Inorganica Chimica Acta, 1994Co-Authors: Joy F Frazier, Frank E. Anderson, Robert L. Clark, Joseph S MerolaAbstract:Abstract Reaction between carbanions and the cationic cyclooctadiene iridium complex, [Ir(COD)(PMe 3 ) 3 ]Cl, gives rise to one of three different products depending on the nature of the carbanion. For resonance stabilized carbanions (indenyl, allyl, benzyl), the products are (2-substituted cyclooct-5-en-1-yl)tris(Trimethylphosphine)iridium complexes derived from nucleophilic attack of the carbanion on one of the double bonds of the coordinated cyclooctadiene. One such complex, (2-benzylcyclooct-5-en-1-yl)tris(Trimethylphosphine)iridium was characterized by single crystal X-ray diffraction and crystallizes in the orthorhombic space group P 2 1 2 1 2 1 with a =9.179(2), b =15.210(3), c =19.474(4) A, V =2718.8 A 3 and Z =4. For non-stabilized anions such as methyl, ethyl and vinyl, the products are bis(Trimethylphosphine)(cyclooctadiene)iridium alkyl (or vinyl) complexes derived from the displacement of PMe 3 from iridium by the carbanion. For non-stabilized secondary or tertiary carbanions, the product is an unsubstituted (cyclooct-5-en-1-yl)tris(methylphosphine)iridium complex derived from the addition of hydride to coordinated cyclooctadiene. Some information and discussion concerning the mechanisms of these reactions are provided.
Jaume Vilarrasa - One of the best experts on this subject based on the ideXlab platform.
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Conversion of ketoximes to ketones with Trimethylphosphine and 2,2′-dipyridyl diselenide
Tetrahedron Letters, 2004Co-Authors: Manuel Martin, Felix Urpi, Gabriel Martı́nez, Jaume VilarrasaAbstract:Abstract Use of Trimethylphosphine (Me 3 P) and 2,2′-dipyridyl diselenide (PySeSePy) is an excellent method for the conversion of ketoximes to the corresponding ketones, since yields higher than 90% are obtained at rt within a few minutes (or hours for the more reluctant substrates, which do not react with Bu 3 P/PhSSPh). In the simplest cases, the reaction can be completed with 30 mol % of PySeSePy, provided that an excess of phosphine is present in the reaction medium.
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conversion of ketoximes to ketones with Trimethylphosphine and 2 2 dipyridyl diselenide
Tetrahedron Letters, 2004Co-Authors: Manuel Martin, Felix Urpi, Gabriel Martinez, Jaume VilarrasaAbstract:Abstract Use of Trimethylphosphine (Me 3 P) and 2,2′-dipyridyl diselenide (PySeSePy) is an excellent method for the conversion of ketoximes to the corresponding ketones, since yields higher than 90% are obtained at rt within a few minutes (or hours for the more reluctant substrates, which do not react with Bu 3 P/PhSSPh). In the simplest cases, the reaction can be completed with 30 mol % of PySeSePy, provided that an excess of phosphine is present in the reaction medium.
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one pot conversion of azides to boc protected amines with Trimethylphosphine and boc on
Tetrahedron Letters, 1998Co-Authors: Xavier Ariza, Felix Urpi, Carles Viladomat, Jaume VilarrasaAbstract:Abstract Reaction of azides with Trimethylphosphine followed by addition of 2-(tert-butoxycarbonyloxyimino)-2-phenyl-acetonitrile (Boc-ON) at −20 °C and stirring at r.t. for 5 h affords the desired Boc-amines in 87–100% yields. Similar yields are obtained by mixing all components together (azide, Me3P, and Boc-ON) in toluene or THF.
Marion A Franks - One of the best experts on this subject based on the ideXlab platform.
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synthesis reactivity and crystal structures of various solvates of fac tris Trimethylphosphine trichloroiridium
Polyhedron, 2013Co-Authors: Joseph S Merola, Marion A Franks, Joy F FrazierAbstract:The synthesis of fac-tris(Trimethylphosphine)iridiumtrichloride is reported and the crystal structure of five different solvates of this compound are analyzed. Compared with the idealized structure calculated with DFT methods, bond angles and distances differ considerably for all of the solvates examined. The utility of fac-tris(Trimethylphosphine)iridiumtrichloride for the synthesis of organometallic compounds of iridium(III) is also demonstrated.
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the basicity of tris Trimethylphosphine cyclooctadiene iridium i
Journal of Organometallic Chemistry, 2013Co-Authors: Joseph S Merola, Marion A FranksAbstract:[Tris-(Trimethylphosphine)(cyclooctadiene)iridium(I)]chloride, [Ir(COD)(PMe3)3]Cl, is very electron rich. In this report, that electron rich character is probed by examining the protonation of the complex at the metal center to form the dicationic [tris-(Trimethylphosphine)(cyclooctadiene)(hydrido)iridium(III)], [HIr(COD)(PMe3)3] þ2 . The exact formulation of the species formed depends on the nature of the Bronsted acid’s counterion. Protonation with hydrogen chloride, fluoroboric acid, and triflic acid are all described and the structure of the dication and some products from further reaction of the dication are elucidated. Simple aqueous acid/base titration of [Ir(COD)(PMe3)3]Cl is described yielding a pKa for [HIr(COD) (PMe3)3] þ2 of 4.2.
Hans-friedrich Klein - One of the best experts on this subject based on the ideXlab platform.
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synthesis of dimethylcobalt iii complexes containing Trimethylphosphine and 2 formyl phenolato or 2 formyl enolato o o ligands
Inorganica Chimica Acta, 2005Co-Authors: Xiaoyan Li, Alexandra Brand, Hans-friedrich KleinAbstract:Abstract Substituted salicylaldehydes [C 6 HR 1 R 2 R 3 (CHO)(OH)] react with CoMe 3 (PMe 3 ) 3 to afford 6-coordinate ( cis -dimethyl)(2-formyl-phenolato) trans -bis(Trimethylphosphine)cobalt(III) compounds Co[C 6 HR 1 R 2 R 3 (CHO)(O)Me 2 ](PMe 3 ) 2 ( 1 : R 1 = H; R 2 = Me; R 3 = tert -Bu; 2 : R 1 , R 2 = C 6 H 4 ; R 3 = H). Accordingly, substituted enolated malonic dialdehydes (CHO–CR 4 CR 5 –OH) react with CoMe 3 (PMe 3 ) 3 to afford 6-coordinate ( cis -dimethyl)(2-formyl-enolato) trans -bis(Trimethylphosphine)cobalt(III) compounds Co[(CHO–CR 4 CR 5 –O)(Me) 2 ](PMe 3 ) 2 ( 3 : R 4 , R 5 = (CH 2 ) 2 C 6 H 4 ; 4 : R 4 = R 5 = C 6 H 5 ). In the molecular structure of 4 , the cobalt atom is centred in an octahedral coordination geometry brought about by a six-membered chelate ring (O:O-ligand), cis -dimethyl and trans -Trimethylphosphine groups. A reaction mechanism is suggested.
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Coordination of ortho and para quinones and oxidation reduction processes in Trimethylphosphine complexes of cobalt and nickel
Inorganica Chimica Acta, 1999Co-Authors: Hans-friedrich Klein, Emmanuel Auer, Ute Lemke, Mathias Lemke, Thomas Jung, Caroline Röhr, Ulrich Flörke, Hans-jürgen HauptAbstract:Abstract The ortho-quinones 9,10-phenanthrenequinone, 1,2-naphthoquinone, and 3,5-di-tert-butyl-benzoquinone-1,2 oxidatively substitute Trimethylphosphine into Ni(PMe3)4 affording molecular compounds containing chelating dioxo ligands of the catecholate type. Using CoMe(PMe3)4 as a substrate the synthesis was extended to tetrachlorobenzoquinone-1,2 and dibenzoyl with retention of the CoMe group. Formally omitting the methyl group, odd-electron complexes were obtained from Co(cyclopentene)(PMe3)3 by reaction with 9,10-phenanthrenequinone or dibenzoyl. The para-quinones 2,5-di-tert-butyl-benzoquinone-1,4 and 2-tert-butyl-naphthoquinone-5,10 displace two Trimethylphosphines in Ni(PMe3)4 to form diene complexes of zerovalent nickel. X-ray crystal structures establish the presence of O:O coordinated catecholato ligands for nickel(II) and cobalt(III) and reveal an η4-diene type quinone ligand coordinated to nickel(0).
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Trimethylphosphine complexes of diorganonickel iv moieties
Organometallics, 1997Co-Authors: Hans-friedrich Klein, Mathias Lemke, Thomas Jung, Caroline Röhr, Ulrich Flörke, Alexandra Brand, Alfred Bickelhaupt, Hans-jürgen HauptAbstract:When coordinated to 2-oxobenzoyl-C,O chelating ligands (O⌒CO) (⌒ = 3-tert-butyl-5-methylphenyl, 3,5-di-tert-butylphenyl, 3-methoxyphenyl, 3,4-benzocyclohexenyl, cyclohexenyl), 18 electron nickel(II) complexes Ni(O⌒CO)(PMe3)3 (1−5) oxidatively add iodomethane affording thermally labile NiIV compounds trans-mer-Ni(Me)I(O⌒CO)(PMe3)2 (6−10) or react with iodine in a ligand dismutation reaction to form stable molecules of trans-Ni(O⌒CO)2(PMe3)2 (21−25), which contain cisoidal acylphenolato chelate rings. Acylphenolato compounds 1−5 react with larger electrophiles [C2H5I, (CH3)2CHI, n-C4H9I, cyclo-C6H11I, CH3COCl, PhCOCl, (CH3)3COCl] in different regioselectivities affording ketones or esters. The square pyramidal bis[n-butyl 2-oxophenyl ketone]nickel(II) complex 16 crystallizes in the monoclinic space group C2/c, while the square planar chloro(phenyl)nickel(II) complex 19 with an ester group in the 2-position crystallizes in the triclinic space group P1. Steric control of C,C-coupling reactions is demonstrate...
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methylnickel compounds containing Trimethylphosphine and salicylaldiminato n o ligands
Inorganica Chimica Acta, 1996Co-Authors: Hans-friedrich Klein, Alfred BickelhauptAbstract:Abstract Methyl(salicylaldiminato[ N : O ])nickel complexes NiMe(2OC 6 H 4 CHNR)PMe 3 (R = Me, Ph, CHMe 2 , CH 2 CH(OMe) 2 , CH 2 CF 2 ) have been prepared from [NiMe(OMe)(PMe 3 )] 2 and the corresponding salicylaldimine. The diamagnetic methylnickel compounds contain the well known six-membered chelate ring and are unreactive towards excess Trimethylphosphine. Steric demand of the N-substituent (R = CMe 3 ) causes ring opening and ligand dismulation reactions at the nickel center.
Karl T. Mueller - One of the best experts on this subject based on the ideXlab platform.
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NMR Characterization of Bronsted Acid Sites in Faujasitic Zeolites with Use of Perdeuterated Trimethylphosphine Oxide
Journal of the American Chemical Society, 2002Co-Authors: Murthy D. Karra, Kevin J. Sutovich, Karl T. MuellerAbstract:The interactions of Bronsted acid sites of H−Y (FAU) with perdeuterated Trimethylphosphine oxide (TMPO-d9) are studied with a set of high-resolution solid-state NMR experiments. Double- and triple-resonance MAS NMR techniques (such as CP, TRAPDOR, and REDOR) verify that the lines in the 31P MAS NMR spectrum are indeed from TMPO interacting with Bronsted acid sites. Replacement of acidic hydrogens in the sodalite cages with sodium cations results in the disappearance of one of the peaks, leading to final assignments of the resonances.
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characterization of acid sites in zeolitic and other inorganic systems using solid state 31p nmr of the probe molecule Trimethylphosphine oxide
Journal of Physical Chemistry B, 1998Co-Authors: Edward F Rakiewicz, Kevin J. Sutovich, Alan W Peters, Richard Franklin Wormsbecher, Karl T. MuellerAbstract:The ability to determine the types and concentrations of acid sites in zeolites and fluid-catalytic cracking systems is important for an increased understanding of structure/performance relationships in these materials. Currently, a variety of thermal methods exist that allow quantitative measurement of the Bronsted acid site concentration. In addition, numerous spectroscopic methods using probe molecules are available for qualitative and quantitative detection of both Bronsted and Lewis acid sites. In studies utilizing solid-state NMR spectroscopy, probe molecules containing 31P nuclei present substantial advantages over probes isotopically enriched with 13C and 15N nuclei. These advantages include increased sensitivity and chemical shift dispersion. While a number of phosphorus-based experiments have probed the interaction of Trimethylphosphine with solid acid catalysts, initial studies of the more stable Trimethylphosphine oxide (TMPO) have only been reported on amorphous silica−alumina surfaces. We no...
