Pincer Compounds

Pincer Compounds PDF Author: David Morales-Morales
Publisher: Elsevier
ISBN: 0128129328
Category : Science
Languages : en
Pages : 756

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Book Description
Pincer Compounds: Chemistry and Applications offers valuable state-of-the-art coverage highlighting highly active areas of research—from mechanistic work to synthesis and characterization. The book focuses on small molecule activation chemistry (particularly H2 and hydrogenation), earth abundant metals (such as Fe), actinides, carbene-pincers, chiral catalysis, and alternative solvent usage. The book covers the current state of the field, featuring chapters from renowned contributors, covering four continents and ranging from still-active pioneers to new names emerging as creative strong contributors to this fascinating and promising area. Over a decade since the publication of Morales-Morales and Jensen's The Chemistry of Pincer Compounds (Elsevier 2007), research in this unique area has flourished, finding a plethora of applications in almost every single branch of chemistry—from their traditional application as very robust and active catalysts all the way to potential biological and pharmaceutical applications. - Describes the chemistry and applications of this important class of organometallic and coordination compounds - Includes contributions from global leaders in the field, featuring pioneers in the area as well as emerging experts conducting exciting research on pincer complexes - Highlights areas of promising and active research, including small molecule activation, earth abundant metals, and actinide chemistry

Pincer Compounds

Pincer Compounds PDF Author: David Morales-Morales
Publisher: Elsevier
ISBN: 0128129328
Category : Science
Languages : en
Pages : 756

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Book Description
Pincer Compounds: Chemistry and Applications offers valuable state-of-the-art coverage highlighting highly active areas of research—from mechanistic work to synthesis and characterization. The book focuses on small molecule activation chemistry (particularly H2 and hydrogenation), earth abundant metals (such as Fe), actinides, carbene-pincers, chiral catalysis, and alternative solvent usage. The book covers the current state of the field, featuring chapters from renowned contributors, covering four continents and ranging from still-active pioneers to new names emerging as creative strong contributors to this fascinating and promising area. Over a decade since the publication of Morales-Morales and Jensen's The Chemistry of Pincer Compounds (Elsevier 2007), research in this unique area has flourished, finding a plethora of applications in almost every single branch of chemistry—from their traditional application as very robust and active catalysts all the way to potential biological and pharmaceutical applications. - Describes the chemistry and applications of this important class of organometallic and coordination compounds - Includes contributions from global leaders in the field, featuring pioneers in the area as well as emerging experts conducting exciting research on pincer complexes - Highlights areas of promising and active research, including small molecule activation, earth abundant metals, and actinide chemistry

Two-in-one pincer type ligands and their metal complexes for catalysis

Two-in-one pincer type ligands and their metal complexes for catalysis PDF Author: Alexander Gers-Barlag
Publisher:
ISBN:
Category :
Languages : de
Pages : 0

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Book Description
The synthesis, characterization and first applications in catalysis of dinuclear metal complexes of the new Two-in-one pincer ligand scaffold are described in this work. Zinc(II) compexes were used to compare structural and electronical features of two derivatives of the ligand system. Reactivity studies revealed a broad range of reactions for a cobalt(II) complex, although detailed analysis of the reaction products was not possible so far. Furthermore, several rhodium(I) complexes have been synthesized and fully characterized. For a rhodium(I) carbonyl complex a dearomatization sequence wa...

The Chemistry of Pincer Compounds

The Chemistry of Pincer Compounds PDF Author: David Morales-Morales
Publisher: Elsevier
ISBN: 0080545157
Category : Science
Languages : en
Pages : 467

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Book Description
Pincer complexes are formed by the binding of a chemical structure to a metal atom with at least one carbon-metal bond. Usually the metal atom has three bonds to a chemical backbone, enclosing the atom like a pincer. The resulting structure protects the metal atom and gives it unique properties.The last decade has witnessed the continuous growth in the development of pincer complexes. These species have passed from being curiosity compounds to chemical chameleons able to perform a wide variety of applications. Their unique metal bound structures provide some of the most active catalysts yet known for organic transformations involving the activation of bonds. The Chemistry of Pincer Compounds details use of pincer compounds including homogeneous catalysis, enantioselective organic transformations, the activation of strong bonds, the biological importance of pincer compounds as potential therapeutic or pharmaceutical agents, dendrimeric and supported materials.* Describes the chemistry and applications of this important class of organometallic and coordination compounds* Covers the areas in which pincer complexes have had an impact* Includes information on more recent and interesting pincer compounds not just those that are well-known

Metal-Ligand Co-operativity

Metal-Ligand Co-operativity PDF Author: Gerard van Koten
Publisher: Springer Nature
ISBN: 3030689166
Category : Science
Languages : en
Pages : 451

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Book Description
This book provides researchers in the fields of organic chemistry, organometallic chemistry and homogeneous catalysis with an overview of significant recent developments in the area of metal-ligand cooperativity, with a focus on pincer architectures. The various contributions highlight the widespread impact of M–L co-operativity phenomena on modern organometallic chemistry and catalyst development. The development of efficient and selective catalytic transformations relies on the understanding and fine control of the various elementary reactions that constitutes a catalytic cycle. Co-operative ligands, which actively participate in bond making and bond breaking together to the metal they support, open up new avenues in this area. In particular, buttressing a weak or reactive metal-ligand bond by flanking coordinating arms in a pincer ligand design is proving a versatile strategy to access robust metal complexes that exhibit unusual and selective reactivity patterns.

Organometallic Pincer Chemistry

Organometallic Pincer Chemistry PDF Author: Gerard van Koten
Publisher: Springer
ISBN: 3642310818
Category : Science
Languages : en
Pages : 363

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Book Description
Gerard van Koten: The Mono-anionic ECE-Pincer Ligand - a Versatile Privileged Ligand Platform: General Considerations.- Elena Poverenov, David Milstein: Non-Innocent Behavior of PCP and PCN Pincer Ligands of Late Metal Complexes.- Dean M. Roddick: Tuning of PCP Pincer Ligand Electronic and Steric Properties.- Gemma R. Freeman, J. A. Gareth Williams: Metal Complexes of Pincer Ligands: Excited States, Photochemistry, and Luminescence.- Davit Zargarian, Annie Castonguay, Denis M. Spasyuk: ECE-Type Pincer Complexes of Nickel.- Roman Jambor and Libor Dostál: The Chemistry of Pincer Complexes of 13 - 15 Main Group Elements.- Kálmán J. Szabo: Pincer Complexes as Catalysts in Organic Chemistry.- Jun-ichi Ito and Hisao Nishiyama: Optically Active Bis(oxazolinyl)phenyl Metal Complexes as Multi-potent Catalysts.- Anthony St. John, Karen I. Goldberg, and D. Michael Heinekey: Pincer Complexes as Catalysts for Amine Borane Dehydrogenation.- Dmitri Gelman and Ronit Romm: PC(sp3)P Transition Metal Pincer Complexes: Properties and Catalytic Applications.- Jennifer Hawk and Steve Craig: Physical Applications of Pincer Complexes.

Late Transition-metal Complexes Supported by Pincer Ligands

Late Transition-metal Complexes Supported by Pincer Ligands PDF Author: Wilson D. Bailey
Publisher:
ISBN:
Category : Alkenes
Languages : en
Pages : 181

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Book Description
Late transition-metal pincer complexes of primarily palladium(II) and platinum(II) have been investigated for their application as catalysts in partial oxidation reactions. The epoxidation of higher olefins using molecular oxygen as the oxidant has been targeted, and the individual reaction steps needed to accomplish this overall transformation are described herein, including: (1) hydrogenolysis of a metal hydroxide (M-OH) species to yield a metal hydride (M-H), (2) insertion of O2 into the M-H bond to form a metal hydroperoxide (M-OOH), and (3) O-atom transfer from the M-OOH to epoxides, yielding a M-OH and completing the catalytic cycle. Previous results from our group on these individual transformations using (tBuPCP)Pd and (tBuPCO)Pd fragments are also reviewed. The requirements for O2 insertion into PdII and PtII hydrides are discussed. An array of cationic, neutral, and anionic Pd-H and Pt-H complexes supported by a tBuPNP backbone were synthesized and evaluated for O2 insertion (tBuPNP = 2,6-bis-(di-tbutylphosphinomethyl)pyridine). Metal-ligand cooperation was observed in the activation of H2 to form neutral hydride complexes. The effect of ligand protonation/deprotonation on the trans influence experienced by the hydride ligand was investigated. No reaction with O2 was observed with the cationic hydrides, while the neutral and anionic forms reacted with O2 at the tBuPNP backbone. The synthesis and characterization of mono- and dinuclear Pd-OH complexes supported by a PCNR pincer ligand (PCNR = (1-(3-((di-tert-butylphosphino)methyl)phenyl)-1H-5-R-pyrazole), R = H, Me) is presented. When R = H, ligand pyrazole "rollover" C-H activation was observed, forming a mixed ligand (PCNH)Pd(μ-OH)Pd(PCC) dinuclear structure. This "rollover" was investigated using DFT computations. The mono- and dinuclear hydroxide species were evaluated for hydrogenolysis. The dinuclear compounds {[(PCNR)Pd]2(μ-OH)}[OTf] reacted under an H2 atmosphere to yield the corresponding dinuclear hydrides {[(PCNR)Pd]2(μ-H)}[OTf]. A mechanistic study on the hydrogenolysis of the μ-bridged hydroxide {[(PCNMe)Pd]2(μ-OH)}[OTf] revealed first order kinetics in both [Pd] and [H2]. Terminal hydrides were not detected, and reduction of the mononuclear hydroxide complexes (PCNR)Pd-OH to Pd0 was observed under H2. The reduction was proposed to proceed through displacement of the pyrazole arm, and was examined by DFT computations. Lastly, a new strategy to promote O-atom transfer from M-OOH to epoxides, the final step in the targeted catalytic cycle, is proposed. Preliminary studies on NNNPyz, NNNEt, and NNMe ligated PdII and PtII are discussed (NNNPyz = 2,6-bis(5-tbutyl-1H-pyrazol-3-yl)pyridine; NNNEt = 2-(5-tbutyl-1H-pyrazol-3-yl)-6-(diethylaminomethyl)pyridine; NNMe = 2-(5-tBu-1H-pyrazol-3-yl)-6-methylpyridine). The NNNPyz ligand, containing two acidic sites in proximity to the fourth site in the square plane, was found to protonate M-O2 complexes, chelate to the metal center and oxidize phosphine substrates. Similar reactivity was observed with NNNEt and NNMe, however hemilability of these ligands resulted in undesired coordination modes.

Organometallic Pincer Chemistry

Organometallic Pincer Chemistry PDF Author: Gerard van Koten
Publisher: Springer
ISBN: 9783642438493
Category : Science
Languages : en
Pages : 0

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Book Description
Gerard van Koten: The Mono-anionic ECE-Pincer Ligand - a Versatile Privileged Ligand Platform: General Considerations.- Elena Poverenov, David Milstein: Non-Innocent Behavior of PCP and PCN Pincer Ligands of Late Metal Complexes.- Dean M. Roddick: Tuning of PCP Pincer Ligand Electronic and Steric Properties.- Gemma R. Freeman, J. A. Gareth Williams: Metal Complexes of Pincer Ligands: Excited States, Photochemistry, and Luminescence.- Davit Zargarian, Annie Castonguay, Denis M. Spasyuk: ECE-Type Pincer Complexes of Nickel.- Roman Jambor and Libor Dostál: The Chemistry of Pincer Complexes of 13 - 15 Main Group Elements.- Kálmán J. Szabo: Pincer Complexes as Catalysts in Organic Chemistry.- Jun-ichi Ito and Hisao Nishiyama: Optically Active Bis(oxazolinyl)phenyl Metal Complexes as Multi-potent Catalysts.- Anthony St. John, Karen I. Goldberg, and D. Michael Heinekey: Pincer Complexes as Catalysts for Amine Borane Dehydrogenation.- Dmitri Gelman and Ronit Romm: PC(sp3)P Transition Metal Pincer Complexes: Properties and Catalytic Applications.- Jennifer Hawk and Steve Craig: Physical Applications of Pincer Complexes.

The Privileged Pincer-Metal Platform: Coordination Chemistry & Applications

The Privileged Pincer-Metal Platform: Coordination Chemistry & Applications PDF Author: Gerard van Koten
Publisher: Springer
ISBN: 3319229273
Category : Science
Languages : en
Pages : 381

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Book Description
The series Topics in Organometallic Chemistry presents critical overviews of research results in organometallic chemistry. As our understanding of organometallic structure, properties and mechanisms increases, new ways are opened for the design of organometallic compounds and reactions tailored to the needs of such diverse areas as organic synthesis, medical research, biology and materials science. Thus the scope of coverage includes a broad range of topics in pure and applied organometallic chemistry, where new breakthroughs are being achieved that are of significance to a larger scientific audience. The individual volumes of Topics in Organometallic Chemistry are thematic. Review articles are generally invited by the volume editors.

Unconventional Pincer Ligands and Their Transition Metal Complexes

Unconventional Pincer Ligands and Their Transition Metal Complexes PDF Author: Caitlin McQueen
Publisher:
ISBN:
Category : Ligands (Biochemistry)
Languages : en
Pages : 404

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Book Description
This thesis describes investigations into unconventional pincer systems incorporating non-classical central donor groups. Direct reaction of 1,3-bis(diphenylphosphinomethyl)-2,3-dihydro-1H-1,3,2-benzodiazaborole (dppBH) with metal complexes and subsequent ligand manipulations have provided novel ruthenium and, for the first time, osmium boryl pincer complexes. The boryl complexes thus prepared have been observed to undergo various subsequent reactions involving the chloride and triphenylphosphine co-ligands to give new complexes. Further reactions of dppBH with complexes dichlorotris(triphenylphosphine)ruthenium(II) and -osmium(II) resulted in the first examples of sigma-borane pincer complexes, which represent intercepted intermediates in the B-H activation process, affording rare structural data for an osmium sigma-borane complex. The B-H bond of the ruthenium complex could be readily cleaved upon ligand manipulation, such as substitution of triphenylphosphine with the pi-acidic carbonyl and isocyanide ligands, which gave the disubstituted boryl complexes via spontaneous loss of HCl. Attempts to isolate a 1,8-diaminonaphthalene-based borane analogue of dppBH proved unsuccessful, though the compound 1,3 bis(diphenylphosphinomethyl)-2,3-dihydroperimidine (PhDHP) was obtained as a side-product in one case. Further investigations into this compound resulted in the development of a convenient one-pot synthesis, which could be extended to the cyclohexyl analogue 1,3 bis(dicyclohexylphosphinomethyl)-2,3-dihydroperimidine (CyDHP). These compounds were observed to react with various platinum group metal complexes to give novel N-heterocyclic carbene (NHC) pincer complexes via double geminal C-H activation of the central methylene group, providing the first examples of perimidine-based NHC inclusion as the central equatorial group of a pincer system. Reactions of dihydroperimidines with group 8 complexes dichlorotris(triphenylphosphine)ruthenium(II) and -osmium(II) have thus provided the novel pincer NHC complexes. However, reactions of PhDHP with dichlorotris(triphenylphosphine)ruthenium and CyDHP with less electron-rich ruthenium precursors instead gave asymmetric PNP coordinated complexes, in which C-H activation had not occurred, though this could be induced thermally in one case. Reactions of PhDHP and CyDHP with chlorotris(triphenylphosphine)rhodium(I) gave 16-electron chloro rhodium(I) NHC pincer complexes, and their reactivity was investigated via co-ligand manipulations and a preliminary catalytic study. The latter revealed that, while this complex was not particularly efficient for most of the reactions investigated, in some cases simple modifications of the co-ligands could substantially improve catalytic activity. Reactions of the pro-ligands with iridium precursors instead favoured the formation of coordinatively saturated complexes. The reaction of CyDHP with chlorobis(cyclooctene)iridium(I) dimer resulted in a dihydrido chloro iridium(III) NHC pincer complex, while reaction with chlorocarbonylbis(triphenylphosphine)iridium(I) instead afforded a sigma perimidinyl hydrido complex, resulting from oxidative addition of only one C-H bond to the metal centre. This was subsequently shown to readily form an NHC complex upon hydride abstraction. It became apparent that, upon reaction of the dihydroperimidine pro-ligands with metal complexes, carbene formation occurs more readily for electron-rich systems, otherwise resulting in either single or no C-H activation. These observations have provided some insight into the mechanism of NHC formation via chelate-assisted C-H activation of these precursors.

Ligand Design in Metal Chemistry

Ligand Design in Metal Chemistry PDF Author: Mark Stradiotto
Publisher: John Wiley & Sons
ISBN: 1118839811
Category : Science
Languages : en
Pages : 448

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Book Description
The design of ancillary ligands used to modify the structural and reactivity properties of metal complexes has evolved into a rapidly expanding sub-discipline in inorganic and organometallic chemistry. Ancillary ligand design has figured directly in the discovery of new bonding motifs and stoichiometric reactivity, as well as in the development of new catalytic protocols that have had widespread positive impact on chemical synthesis on benchtop and industrial scales. Ligand Design in Metal Chemistry presents a collection of cutting-edge contributions from leaders in the field of ligand design, encompassing a broad spectrum of ancillary ligand classes and reactivity applications. Topics covered include: Key concepts in ligand design Redox non-innocent ligands Ligands for selective alkene metathesis Ligands in cross-coupling Ligand design in polymerization Ligand design in modern lanthanide chemistry Cooperative metal-ligand reactivity P,N Ligands for enantioselective hydrogenation Spiro-cyclic ligands in asymmetric catalysis This book will be a valuable reference for academic researchers and industry practitioners working in the field of ligand design, as well as those who work in the many areas in which the impact of ancillary ligand design has proven significant, for example synthetic organic chemistry, catalysis, medicinal chemistry, polymer science and materials chemistry.