Download or read book Structure reactivity Relationships in Reactions of 1 3 diaralallyl Derivatives and of the Corresponding Palladium Complexes written by Konstantin Troshin and published by . This book was released on 2012 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structure reactivity Relationships in Reactions of 1 3 diarylallyl Derivatives and of the Corresponding Palladium Complexes written by Konstantin Troshin and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metal Complexes written by Peter Maitlis and published by Elsevier. This book was released on 2012-12-02 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Organic Chemistry of Palladium, Volume 1: Metal Complexes deals with the number of organic reactions that can be catalyzed by palladium, particularly as regards the structures bonding, and reactions of the metal complexes. The book discusses monodentate ligands which are either neutral (carbonyls, isonitriles, carbenes) or anionic (methyl, phenyl, ethynyl, hydride). The text also examines the complexes formed by 1,3-. 1,4-, and 1,5-diolefins where four carbon atoms are bound to the metal. Palladium (II) can undergo a reaction with the 1,3-dienes and results in a ?-allylic complexes where only three carbon atoms are coordinated to the metal. (The bonding situation in complexes 1,4- and 1,5-dienes, where no great interaction between the olefins are similar to that in monoolefin complexes, is straightforward), Olefins can also react with palladium chloride in protic solvents to produce ketones (or aldehydes) or organic coupling products. Some experiments conducted by Huttel et al shows that some palladium was precipitated from the reactions giving lower yields, resulting in various aldehydes and ketones as by products. The book also discusses cyclopentadienyl and benzene complexes. The text can prove beneficial for researchers, investigators and scientists whose works involve organic chemistry, analytical chemistry, physical chemistry and inorganic chemistry.
Download or read book Synthesis and Reactivity of Palladium Complexes that Contain Redox active Verdazyl Ligands written by Corey A. Sanz and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the synthesis, characterization and reactivity of a series of palladium complexes that contain redox-active verdazyl ligands. This work was motivated by the possibility of discovering new and interesting reactivity that may eventually lead to the development of new chemical reactions. A bidentate verdazyl radical ligand that contains an aryl phosphine was synthesized. Reaction of this ligand with (PhCN)2PdCl2 yielded a square planar (verdazyl)PdCl2 complex. Structural and spectroscopic data suggest that this compound consists of a ligand-centered radical coordinated to a Pd(II) center. The radical complex was chemically reduced by one-electron to generate a binuclear chloride-bridged [(verdazyl)PdCl]2 complex. In this reduced complex, both metals were still Pd(II) and the verdazyl ligand was determined to be in its singly reduced, monoanionic charge state. The original radical PdCl2 complex could be regenerated via one-electron oxidation of the reduced complex using PhICl2. The verdazyl ligands in the reduced complex could also be reversibly protonated to generate "leuco" verdazyl complex (verdazyl-H)PdCl2. Reaction of the radical (verdazyl)PdCl2 complex with water triggers a ligand-centered redox disproportionation reaction. A series of bis(verdazyl) palladium complexes were synthesized using a bidentate pyridine-substituted verdazyl ligand. Reaction of two equivalents of radical ligand with (CH3CN)4Pd2+ yielded a (verdazyl)2Pd(solvent)2+ complex (solvent = CH3CN or DMSO). In this complex, one verdazyl radical ligand chelates to palladium and the other binds as a monodentate ligand. Two-electron reduction of this complex generated a (verdazyl)2Pd complex in which two monoanionic verdazyl ligands are bound to a central Pd(II) ion. This reduced complex could also be made via reaction of 0.5 equivalents of Pd(0)2(dba)3 with two equivalents of radical ligand. In this reaction, the metal is oxidized by two electrons and each ligand is reduced by a single electron. Two-electron oxidation of the reduced complex in the presence of DMSO yielded the original bis(radical)complex, (verdazyl)2Pd(DMSO)2+. Chlorination of the reduced complex using one equivalent of PhICl2 (two-electron oxidation) resulted in dissociation of one verdazyl ligand to afford a 1:1 mixture of free verdazyl : (verdazyl)PdCl2, in which both of the verdazyls are neutral radicals. Reaction of the reduced complex with 0.5 equivalents of PhICl2 (one-electron oxidation) yielded a (verdazyl)2PdCl complex that contained a bidentate reduced verdazyl ligand and a monodentate radical ligand. All three of the oxidation reactions described above adhere to ligand-centered redox chemistry. Reaction of the reduced (verdazyl)2Pd complex with excess HCl resulted in protonation of both the anionic verdazyl ring and the pyridyl group to generate a leuco/pyridinium tetrachloropalladate salt, (verdazyl-H2)2(PdCl4). The protonated salt could be converted back to the original (verdazyl)2Pd complex by deprotonation with water. Palladium complexes of a tridentate NNN-chelating verdazyl ligand were prepared and their redox chemistry was explored. Reaction of the radical ligand with (CH3CN)4Pd2+ yielded radical complex (verdazyl)Pd(NCCH3)2+. The tridentate ligand was also prepared in its reduced, leuco form (verdazyl-H). Reaction of the leuco verdazyl with (CH3CN)2PdCl2 generated HCl and a (verdazyl)PdCl complex in which the ligand is in its monoanionic charge state. The reduced (verdazyl)PdCl complex was reacted with AgBF4 to afford (verdazyl)Pd(NCCH3)+ via chloride abstraction; the verdazyl remained in its reduced charge state following the reaction. Both reduced complexes (chloro and acetonitrile) were oxidized by a single electron to afford the corresponding radical complexes. These radical complexes could be reduced by a single electron to regenerate the original reduced complexes. Like the previous two projects, all of the redox chemistry was ligand-centered. The reactivity of these complexes with primary amines was also explored. Reaction of radical complex (verdazyl)Pd(NCCH3)2+ with n-butylamine resulted in one-electron reduction of the verdazyl ligand. We were unable to determine the mechanism of the reaction, but the reactivity that was observed demonstrates the potential for verdazyl-palladium complexes to be used in the design of new radical reactions.
Download or read book Synthesis Reactivity and Catalytic Applications of Ruthenium and Palladium Complexes Supported by New Pincer Ligands written by Morgan C. MacInnis and published by . This book was released on 2011 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT continued: These transfer hydrogenation studies are among the first catalytic studies of silyl-pincer complexes and establish [R-PSiP]M species as viable candidates for catalysis. The synthesis and reactivity of 4- and 5-coordinate RuII complexes featuring the [Cy-PSiP] ligand were explored. Reaction of [Cy-PSiP]H with [(p-cymene)RuCl2]2 in the presence of NEt3 and PCy3 resulted in the formation of ([Cy-PSiP]RuCl)2, which serves as a precursor to a series of unprecedented 4-coordinate, formally 14-electron [Cy-PSiP]RuX (X = NHAr, N(SiMe3)2, OtBu) complexes that feature an unusual trigonal pyramidal geometry at Ru. The reactivity of these novel diamagnetic complexes is described, including the reaction of [Cy-PSiP]RuOtBu with amine-boranes resulting in the formation of rare bis(?-BH) complexes. Computational studies confirmed the key role of the strongly ?-donating silyl group of the Cy-PSiP ligand in facilitating the synthesis of such low-coordinate Ru species and enforcing the unusual trigonal pyramidal geometry. The mechanism of ammonia-borane activation was also examined computationally. Lastly, the synthesis and structural characterization of PdII complexes supported by the pincer-like bis(amino)phosphido ligand [?3-(2-Me2NC6H4)2P]- ([NPN]) is described. Examples of ?1-, ?2-, and ?3-NPN coordination to Pd are described, as is the catalytic activity of ([NPN]PdX)2 (X = Cl, OAc, OTf) complexes in the Heck olefin arylation reaction. In an effort to discourage the formation of phosphido-bridged dinuclear complexes, pre-coordination of the Lewis acid BPh3 to [NPN] was pursued. Upon reaction of [N(P?BPh3)N]K with [PdCl(C3H5)]2, the ?1-allyl complex [?3-N(P?BPh3)N]Pd(?1-C3H5) was isolated, which establishes the coordination of a Lewis acid to the phosphido donor of the [NPN] ligand as a viable strategy for encouraging the formation of mononuclear ?3-NPN complexes.
Download or read book Synthetic Structural and Mechanistic Studies of Palladium Complexes Supported by Sterically Encumbering M terphenyl Isocyanides written by Liezel Ann Labios and published by . This book was released on 2012 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: The two-coordinate binary Pd(0) isocyanide monomer Pd(CNArDipp2)2 was prepared using the sterically encumbering m-terphenyl isocyanide ligand CNArDipp2 (ArDipp2 = 2,6-(2,6-(iPr)2C6H2)2C6H3). Building upon the isolobal relationship between [Pi]-acidic isocyanides and C[Omicron], Pd(CNArDipp2)2 was targeted as a stable analogue to the highly reactive binary carbonyl species Pd(C[Omicron])2. The electron-rich nature of Pd(CNArDipp2)2 was demonstrated by its reactivity towards elecrophilic and Lewis acidic substrates such as I2, Me[Omicron]Tf, and Tl[Omicron]Tf. In addition, the ability of Pd(CNArDipp2)2 to oxidatively add across C--Br bonds of aryl bromides made it a promising catalyst precursor for organic cross-coupling reactions. Pd(CNArDipp2)2 mediated the Suzuki-Miyaura cross-coupling of unactivated aryl bromides and aryl boronic acids with 1 mol % catalyst loading at room temperature. Moderate activity was observed with Pd(CNArDipp2)2, and was attributed to the presence of an unnecessary equivalent of ligand on the complex. Kinetic studies on the oxidative addition step provided evidence for a dissociative mechanism, which thereby implied the involvement of a monoligated [Pd(0)L] species. Synthetic approaches to complexes containing a 1:1 L/Pd ratio culminated in the isolation and structural characterization of [Pd([eta]2-Dipp-[mu]-CNArDipp)]3. This complex is a trinuclear aggregate of [Pd(0)L] and is catalytically competent in Suzuki-Miyaura cross-coupling reactions. Most notably, [Pd([eta]2-Dipp-[mu]-CNArDipp)]3 exemplifies the ability of sterically encumbering [Pi]-acidic isocyanide ligands to stabilize the highly reactive and electron-rich monoligated [Pd(0)L] species. Further, Pd(CNArDipp2)2 was employed to probe the coordination chemistry of redox non-innocent ArN[Omicron] ligands. Remarkably, addition of 2 equiv of PhN[Omicron] to Pd(CNArDipp2)2 generated the complex Pd([kappa]1-N-PhN[Omicron])2(CNArDipp2)2, which is the first metal complex containing ([eta]1-N-PhN[Omicron])·1− units to be structurally characterized. Magnetic susceptibility measurements and broken symmetry calculations confirmed the singlet diradical electronic structure of this complex in the solid state. However, spectroscopic studies indicated that Pd([kappa]1-N-PhN[Omicron])2(CNArDipp2)2 can only be observed at low temperature in solution. Complexation of two ArN[Omicron] units to Pd(CNArDipp2)2 in solution at room temperature was achieved using p-[Omicron]CH-C6H4N[Omicron]. The resulting complex Pd([kappa]1-N-p-[Omicron]CH-C6H4N[Omicron])2(CNArDipp2)2 also exhibited paramagnetism in solution, unlike its PhN[Omicron] derivative. Additional ArN[Omicron] derivatives of Pd(CNArDipp2)2 were isolated and characterized, and the chemistry pertaining to these compounds is discussed.
Download or read book Metal Complexes written by Peter Maitlis and published by Academic Press. This book was released on 1971-01-28 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Organic Chemistry of Palladium, Volume 1: Metal Complexes deals with the number of organic reactions that can be catalyzed by palladium, particularly as regards the structures bonding, and reactions of the metal complexes. The book discusses monodentate ligands which are either neutral (carbonyls, isonitriles, carbenes) or anionic (methyl, phenyl, ethynyl, hydride). The text also examines the complexes formed by 1,3-. 1,4-, and 1,5-diolefins where four carbon atoms are bound to the metal. Palladium (II) can undergo a reaction with the 1,3-dienes and results in a ?-allylic complexes where only three carbon atoms are coordinated to the metal. (The bonding situation in complexes 1,4- and 1,5-dienes, where no great interaction between the olefins are similar to that in monoolefin complexes, is straightforward), Olefins can also react with palladium chloride in protic solvents to produce ketones (or aldehydes) or organic coupling products. Some experiments conducted by Huttel et al shows that some palladium was precipitated from the reactions giving lower yields, resulting in various aldehydes and ketones as by products. The book also discusses cyclopentadienyl and benzene complexes. The text can prove beneficial for researchers, investigators and scientists whose works involve organic chemistry, analytical chemistry, physical chemistry and inorganic chemistry.
Download or read book Investigation of Structure Reactivity Relationships of Arylpalladium Complexes in Transmetalations with Arylzinc Reagents written by Sina Patricia Zucker and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chiral Tricyclic 1 2 3 Triazol 3 Ylidene Pd II Complexes of Cyclohexene Oxide Scaffold written by manoj kumar gangwar and published by . This book was released on 2020 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: We herein report the two novel well-defined palladium(II) complexes 1(b-c), of the chiral N-fused tricyclic 1,2,3-triazolium-derived mesoionic carbenes (MIC) ligand 1a. The chiral tricyclic PEPPSI type complex namely, trans-{2-methyl-(5aS,9aS)-5a,6,7,8,9,9a-hexahydro-4H-benzo[b][1,2,3]triazolo[1,5-d][1,4]oxazin-3-ylidene}PdI2(pyridine)} (1b), and the chiral tricyclic bis(tz-MIC)-palladium complex namely, {2-methyl-(5aS,9aS)-5a,6,7,8,9,9a-hexahydro-4H-benzo[b][1,2,3]triazolo[1,5-d][1,4]oxazinium-3-ylidene}2PdCl2} (1c). The chiral tricyclic (tz-MIC)PdI2(pyridine) type PEPPSI complex (1b) was obtained by direct reaction of the corresponding chiral tricyclic 1,2,3-triazolium-derived mesoionic carbenes (MIC) ligand 1a, by treatment with PdCl2 in the presence of K2CO3 as a base in pyridine in 87% yield. (Scheme 1). The chiral tricyclic 1,2,3-triazolium iodide salt (1a) was converted to its in-situ silver analogue by reaction with Ag2O and then subsequently upon treatment with (COD)PdCl2 to produce the chiral tricyclic (tz-MIC)2PdCl2 type palladium complex (1c). All these palladium complexes were isolated for the first time and structurally characterized by 1H NMR and 13C{1H}-NMR spectroscopy, FT-IR spectroscopy, mass spectrometry, elemental analysis and single crystal X-ray crystallography.
