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Ferrocenyl Carbenes As Redox Switchable Ligands In Gold Catalysis Synthesis Redox Behaviour And Elucidation Of Side Reactions
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Book Synopsis Ferrocenyl Carbenes as Redox-Switchable Ligands in Gold Catalysis - Synthesis, Redox-Behaviour and Elucidation of Side Reactions by : Philipp Veit
Download or read book Ferrocenyl Carbenes as Redox-Switchable Ligands in Gold Catalysis - Synthesis, Redox-Behaviour and Elucidation of Side Reactions written by Philipp Veit and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Synthesis of Ferrocene-based Ligands and Their Applications in Redox-switchable Catalysis for Selective Hydroamination Reactions by : Brian Raymond Lydon
Download or read book Synthesis of Ferrocene-based Ligands and Their Applications in Redox-switchable Catalysis for Selective Hydroamination Reactions written by Brian Raymond Lydon and published by . This book was released on 2013 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis contains results from three different projects. The first project focused on the synthesis of monoanionic ferrocene-based N, P ligands. 1-(tert-butyldimethylsilyl)amino-1'-diphenylphosphinoferrocene (fc(TBSNH)(PPh2)) was successfully synthesized and characterized by 1H, 31P, 13C NMR spectroscopy, and elemental analysis. Unfortunately, coordination to group 3 metal complexes was unsuccessful. The second project focused on the synthesis of redox-active ferrocene-based ligands and their applications in selective intramolecular hydroamination. Redox-active ligands can be used as a reversible trigger to control catalytic reactivity. Preliminary results observed by 1H NMR spectroscopy suggest that [1,1'-ferrocenedi(thio(3,5-di-tert-butyl-2-phenoxide)]Zr dibenzyl ((thiolfan2)ZrBn2) shows selectivity between primary and secondary alkeneamines depending on the oxidation state of the iron center. The final project was a computational study using density functional theory (DFT) to understand recent experimental findings involving ferrocene-functionalized biodegradable polymers. Gibbs free energy for six cyclic carbonate monomers and three [delta]-valerolactone monomers was calculated. Computational results correlated strongly with experimental data in that [delta]-valerolactones, which could not be polymerized, had a higher Gibbs free energy than cyclic carbonates, which could be polymerized.
Book Synopsis N-Heterocyclic Carbenes in Transition Metal Catalysis by : Frank Glorius
Download or read book N-Heterocyclic Carbenes in Transition Metal Catalysis written by Frank Glorius and published by Springer Science & Business Media. This book was released on 2007 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book leading experts have surveyed major areas of application of NHC metal complexes in catalysis. The authors have placed a special focus on nickel- and palladium-catalyzed reactions, on applications in metathesis reactions, on oxidation reactions and on the use of chiral NHC-based catalysts. This compilation is rounded out by an introductory chapter and a chapter dealing with synthetic routes to NHC metal complexes.
Book Synopsis N-heterocyclic Carbenes by : Silvia Díez-González
Download or read book N-heterocyclic Carbenes written by Silvia Díez-González and published by Royal Society of Chemistry. This book was released on 2011 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last fifteen years, N-heterocyclic carbenes (NHCs) have mostly been used as ancillary ligands for the preparation of transition metal-based catalysts. Compared to phosphorus-containing ligands, NHCs tend to bind more strongly to metal centres, avoiding the necessity for the use of excess ligand in catalytic reactions. The corresponding complexes are often less sensitive to air and moisture, and have proven remarkably resistant to oxidation. Recent developments in catalysis applications have been facilitated by the availability of carbenes stable enough to be bottled, particularly for their use as organocatalysts. This book shows how N-heterocyclic carbenes can be useful in various fields of chemistry and not merely laboratory curiosities or simple phosphine mimics. NHCs are best known for their contribution to ruthenium and palladium-catalysed reactions but the scope of this book is much broader. The synthesis of NHC ligands and their corresponding metal complexes are covered in depth. Moreover, the biological activity of NHC-containing complexes, as well as an overview of their theoretical aspects are included. Such metal species are further examined, not only in terms of their catalytic applications, but also of their stereoelectronic parameters and reactivity/stability. Finally, special attention is given to the hot topic of organocatalysis. The book will be of interest to postgraduates, academic researchers and those working in industry.
Book Synopsis Synthesis of Metal Complexes Supported by Ferrocene-based Ligands for Tandem Catalysis and Applications Toward Liquid Cell Quantum Sensing by : Yi Shen
Download or read book Synthesis of Metal Complexes Supported by Ferrocene-based Ligands for Tandem Catalysis and Applications Toward Liquid Cell Quantum Sensing written by Yi Shen and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developing methodologies to synthesize high-value products efficiently from simple substrates with control over the reactivity and selectivity is highly favored by the chemical industry. Employing assisted tandem catalysis, where serial reactions can be carried out in one pot, to achieve streamlined complex syntheses significantly reduces the number of steps and waste. Harnessing spatial and temporal control in catalysis enables approaches toward one-pot transformations and allows the integration of several catalytic processes. Ferrocene-based ligand-supported metal complexes represent a promising class of catalysts that can incorporate redox control over catalytic processes. We have developed a redox-controlled selective hydroamination reaction catalyzed by (thiolfan*)Zr(NEt2)2 (thiolfan*= 1, 1'-bis (2,4-di-tert-butyl-6-thiophenoxy)ferrocene). In situ switching of the catalyst's state during the reaction enables selectivity toward different substrates (Chapter 2).Incorporating the greenhouse gas CO2 into N-carboxyanhydrides (NCAs) followed by subsequent NCA utilization illustrates the possibility of integrating two synthetic steps in one vessel to afford a valuable material with possible CO2 recycling. To demonstrate the immense potential of integrating multi-step transformations in one pot, we developed a set of sustainable conditions for NCA synthesis (Chapter 3). Moreover, several metal catalysts supported by ferrocene-based ligands were found to catalyze NCA polymerization in the presence of a co-catalyst. To establish an integrated system composed of two incompatible processes, we aimed to compartmentalize the active reagents for each step. The structure of the ferrocene-based pro-ligand was modified for surface anchoring. Our efforts toward immobilizing ferrocene-supported metal catalysts onto conductive surfaces pave the way of achieving spatiotemporal control over the processes of NCA synthesis and polymerization (Chapter 4). In addition to the redox-switchable characteristic, ferrocene-based compounds provide a unique platform to support lanthanides and engender distinctive optical properties to them. We synthesized and characterized a series of ytterbium complexes displaying an ultra-narrow absorption in the ultraviolet-visible (UV-Vis) region. The extraordinarily narrow linewidth observed for (thiolfan)YbCl(THF) (thiolfan = 1,1'-bis(2,4-di-tert-butyl-6-thiomethylenephenoxy)ferrocene) allows us to investigate its applications toward magnetic field and liquid cell quantum sensing (Chapter 5).
Book Synopsis Ferrocene-based Redox-switchable Ligands by : Alan Martin Allgeier
Download or read book Ferrocene-based Redox-switchable Ligands written by Alan Martin Allgeier and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new redox-active HE(II) sequestering ligand, ($\eta\sp5$-C$\rm\sb5H\sb4SCH\sb2CH\sb2SH)\sb2$Fe, 5, has been synthesized and characterized. Ligand 5 undergoes a reaction with Hg(ClO$\sb4)\sb2$, which has been detected by $\sp1$H NMR spectroscopy and cyclic voltammetry in DMSO.
Book Synopsis Metal Carbenes in Organic Synthesis by : K H Dtz
Download or read book Metal Carbenes in Organic Synthesis written by K H Dtz and published by Springer Science & Business Media. This book was released on 2004-09-21 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: With contributions by numerous experts
Book Synopsis Synthesis, Reactivity, and Multi-electron Redox Behavior of a Bis(phenoxy)amide Ligand Coordinated to a Tantalum Metal Center by : Ryan A. Zarkesh
Download or read book Synthesis, Reactivity, and Multi-electron Redox Behavior of a Bis(phenoxy)amide Ligand Coordinated to a Tantalum Metal Center written by Ryan A. Zarkesh and published by . This book was released on 2012 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes the synthesis and reactivity of tantalum metal complexes containing a tridentate redox-active ligand. Fundamental studies have focused on utilizing the redox-active ligand to store multiple electron equivalents for oxidative addition and reductive elimination reactions. Chapter 1 provides an introduction to the characteristics of redox-active ligands and provides an overview of group transfer reactions involving redox-active ligands. The previous published results of bidentate redox-active ligands coordinated to Group IV d0 metals are discussed in terms of their decomposition side reactions. Chapter 2 describes the coordination of a known tridentate redox-active bis(phenoxy)amide ligand, (ONO), to a d0 tantalum(V) metal center and the examination of the redox properties of the resulting chloro oxidation products by electrochemical and spectroscopic methods. Chapter 3 examines the reactivity of the (ONO)TaR2 complexes in the general context of organometallic chemistry with a focus on protonolysis and reactivity with aryl azides, a known source of nitrene fragments upon oxidation. Chapter 4 examines the reactivity of the (ONO)TaX2 (X = Me, Cl) compounds with bulky diazoalkanes, a known carbene transfer reagent. The (ONO)TaCl2 complex proved to be a competent catalyst to generate cyclopropanes from styrene and the corresponding diazoalkane. Chapter 5 explores the utilization of the (ONO) ligand to store electron equivalents for the catalytic nitrene-nitrene coupling reactions with organoazides to afford organodiazenes. Finally, Chapter 6 addresses the electronic considerations of a related redox-active triamido ligand in an effort to tune the ligand's redox potentials.
Book Synopsis Heteroaryl Carbene Complexes by : Belinda Van der Westhuizen
Download or read book Heteroaryl Carbene Complexes written by Belinda Van der Westhuizen and published by . This book was released on 2013 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Functionalised N-Heterocyclic Carbene Complexes by : Olaf Kühl
Download or read book Functionalised N-Heterocyclic Carbene Complexes written by Olaf Kühl and published by John Wiley & Sons. This book was released on 2010-02-02 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: N-heterocyclic carbenes (NHCs) have found increasing use as reagents for a range of organic transformations and in asymmetric organocatalysis. The performance of these molecules can be improved and tuned by functionalisation. Functionalised carbenes can anchor free carbenes to the metal site, introduce hemilability, provide a means to immobilise transition metal carbene catalysts, introduce chirality, provide a chelate ligand or bridge two metal centres. NHC can be attached to carbohydrates and campher, derived from amino acids and purines, they can be used as organocatalysts mimicking vitamin B1 or as weak “solvent” donors in lanthanide chemistry. Functionalised N-Heterocyclic Carbene Complexes describes major trends in functionalised NHC ligands, aiming to assist readers in their attempts to develop and apply their own functionalised carbenes. After an introduction to the chemistry and behaviour of NHC, the book gives a detailed description of functionalised carbenes and their complexes according to a range of functional groups, each with a discussion of the synthetic route, structure, stability and performance. Functionalised N-Heterocyclic Carbene Complexes is an essential guide to fine-tuning this important class of compounds for practitioners, researchers and advanced students working in synthetic organometallic and organic chemistry and catalysis.
Book Synopsis Ferrocene-Chelating Heteroscorpionate Ligands Support Zinc Complexes as Redox Switchable Catalysts by : Tate Reuter
Download or read book Ferrocene-Chelating Heteroscorpionate Ligands Support Zinc Complexes as Redox Switchable Catalysts written by Tate Reuter and published by . This book was released on 2018 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ferrocene-chelating heteroscorpionate compounds based on [fc(PPh2)(BH[(3-R-5-R'-1-H)2pz]2)] (fc = 1,1'-ferrocenediyl, pz = pyrazole) are studied and characterized for their role in the synthesis of block copolymers. The ferrocene scaffold is part of a heteroscorpionate ligand that supports late transition metals. A zinc complex, [fc(PPh2)(BH[(3,5-Me-1H)2pz]2)]Zn( -OCH2Ph), was synthesized previously and shown to exist in a dimeric state. Herein, the substituents on the pyrazole fragments of the scorpionate are replaced with bulkier groups to force the formation of a monomeric compound in order to arrive at a redox switchable catalyst.
Book Synopsis N-Heterocyclic Carbenes in Transition Metal Catalysis and Organocatalysis by : Catherine S.J. Cazin
Download or read book N-Heterocyclic Carbenes in Transition Metal Catalysis and Organocatalysis written by Catherine S.J. Cazin and published by Springer Science & Business Media. This book was released on 2010-10-04 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: N-Heterocyclic Carbenes in Transition Metal Catalysis and Organocatalysis features all catalytic reactions enabled by N-heterocyclic carbenes (NHCs), either directly as organocatalysts or as ligands for transition metal catalysts. An explosion in the use of NHCs has been reported in the literature during the past seven years making this comprehensive overview highly apropos. The book begins with an introductory overview of NHCs which could have been subtitled all you need to know about NHCs. The main body of the book is dedicated to applications of NHCs in catalysis. In addition to the success stories of NHCs in metathesis, NHCs in cross coupling and more recently NHCs in organocatalysis, all other less publicized areas are also covered. As the success of NHCs is generally attributed to their potential to stabilize metal centres, the inclusion of a chapter on the decomposition of NHC catalysts is pertinent. The book closes with a chapter describing the applications of NHCs in industrial processes, which is the first coverage of its kind, and brings a unique industrial context to this book. Included in this book: Historical aspects of NHCs Synthetic pathways to NHC precursors, free NHCs and complexes Methods of characterisation of NHCs and related complexes Electronic properties of NHCs Steric properties of NHCs and models for their description NHCs for metathesis and cross-coupling reactions NHCs as organocatalysts NHC Transition-Metal mediated oxidations, additions to multiple bonds, polymerisation and oligomerisation, cyclisations, direct arylations, reactions involving CO, C-F and C-H bond activation, ... Decomposition of NHC-containing catalysts Industrial applications involving NHC-containing catalysts N-Heterocyclic Carbenes in Transition Metal Catalysis and Organocatalysis provides a fresh view of NHCs since most contributors are young emerging researchers in the field of homogeneous catalysis using NHCs. This group of contributors is complemented by highly established academic researchers and an industrialist. This book is comprehensive, from the basic features of NHCs to the latest advances, hence it is suitable for both the novice and the expert.
Book Synopsis Novel Diaminocarbene Ligands and Their Applications in Ruthenium-based Metathesis Catalysts by : Evelyn Louise Rosen
Download or read book Novel Diaminocarbene Ligands and Their Applications in Ruthenium-based Metathesis Catalysts written by Evelyn Louise Rosen and published by . This book was released on 2010 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the ever expanding utility of transition metal catalysis, there has been a thrust both to develop catalysts with unique selectivites or activites, and to understand the factors which govern these characteristics at both a fundamental and practical level. Olefin metathesis has become an essential reaction for the synthesis of small molecules in addition to polymeric materials. We have pursued two distinct ligand classes based on diaminocarbenes with novel architectures to address specific limitations within this useful class of reactions: 1) limited access to polymeric materials with controlled microstructures and 2) poor stereoselectivity in Ru-catalyzed cross-metathesis (CM) reactions. Numerous phosphines and N-heterocyclic carbenes (NHCs) have been used as ligands for Ru metathesis catalysts, and the resulting activity is very sensitive to their steric and electronic nature. We envisioned that we could take advantage of this dependence by developing a catalyst with tunable ligand donicity. Redox-switchable ligands can lead to catalysts whose selectivity and/or activity are dependent upon the ligand oxidation state. Towards this purpose, we have developed a ligand which incorporates a 1,1'-disubstituted ferrocene moiety into the backbone of a diaminocarbene (FcDAC). Upon ligation of FcDAC to various transition metals, we were able to use cyclic voltammetry and a spectroelectrochemical FT-IR experiment to show electronic communication between FcDAC and the coordinated metal. We then pursued Ru metathesis catalysts incorporating these ligands. The ring-opening metathesis polymerization of 1,5-cyclooctadiene was studied using [(FcDAC)(PPh3)Cl2Ru=(3-phenylindenylid-2-ene)] as the catalyst. Chemical redox reactions were used to establish the ability of FcDAC to impart redox-tunable properties to Ru metathesis catalysts. A new ligand class pioneered in our group, N-aryl, N-alkyl acyclic diaminocarbenes (ADCs), was also studied in various Ru metathesis catalysts. To our delight, these catalysts showed lower E : Z ratios than analogous NHC ligands in two representative CM reactions. We also investigated the conformational diversity of these differentially substituted ADCs given their ability to rotate about their C-N bonds, in particular, to determine how this might influence their donicity. Complexes of the type [(ADC)Ir(COD)Cl] and [(ADC)Ir(CO)2Cl] were studied, given the wealth of structural and spectral data available for analogous compounds incorporating related ligand classes. Different conformations resulted depending on the N-substituents and the nature of the metal complex. Interestingly, the electron donating ability of ADC ligands was found to depend on their conformation, as evidenced by FT-IR and cyclic voltammetry. This established a new avenue for tuning the donor properties of differentially substituted ADC ligands. The unique properties of these novel ligand classes were demonstrated in Ru metathesis catalysts. However, on a broader level, these ligands are expected to have utility in diverse catalytic applications.
Book Synopsis N-Heterocyclic Carbenes in Organocatalysis by : Akkattu T. Biju
Download or read book N-Heterocyclic Carbenes in Organocatalysis written by Akkattu T. Biju and published by John Wiley & Sons. This book was released on 2019-05-06 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summarizing the emerging field of N-heterocyclic carbenes used in organocatalysis, this is an excellent overview of the synthesis and applications of NHCs focusing on carbon-carbon and carbon-heteroatom bond formation. Alongside comprehensive coverage of the synthesis, characteristics and applications, this handbook and ready reference also includes chapters on NHCs for polymerization reactions and natural product synthesis.
Book Synopsis Symmetrically and Non-symmetrically Substituted 1,1'-ferrocenes as Supporting Ligands for Divalent Metals in Catalysis by : Mark Abubekerov
Download or read book Symmetrically and Non-symmetrically Substituted 1,1'-ferrocenes as Supporting Ligands for Divalent Metals in Catalysis written by Mark Abubekerov and published by . This book was released on 2017 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: The synthesis of new polymers is motivated by the limitations of current materials. Recently, interest in copolymers containing blocks that display different or complementary properties has been increasing since these materials have potential for further performance enhancements. Inspired by recent developments in olefin polymerization catalysts, and based on the interest of the Diaconescu group in the reactivity of complexes supported by ferrocene-based chelating ligands, we developed a new ferrocene-chelating heteroscorpionate supporting ligand and investigated its applications in combination with late transition metals to redox-switchable catalysis for the production of multiblock copolymers. Additionally, we began investigations into the influence of the iron-secondary metal interactions on redox-switchable catalysis in complexes supported by symmetrically substituted, neutral ferrocene-based ligands.
Book Synopsis Design of New Monodentate Ligands for Regioselectivity and Enantioselectivity Tuning in Late Transition Metal Catalysis by : Aaron A. Ruch
Download or read book Design of New Monodentate Ligands for Regioselectivity and Enantioselectivity Tuning in Late Transition Metal Catalysis written by Aaron A. Ruch and published by . This book was released on 2016 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability of gold(I) to activate many types of unsaturated bonds toward nucleophilic attack was not widely recognized until the early 2000s. One major challenge in gold catalysis is the control over regioselectivity when there are two or more possible products as a result of complicated mechanistic pathways. It is well know that the choice of ligand can have dramatic effects on which pathway is being followed but very rarely are the reasons for this selectivity understood. The synthesis of new acyclic diaminocarbenes was developed and a study of the ligand effects on the regioselectivity of a gold-catalyzed domino enyne cyclization hydroarylation reaction and a Nazarov cyclization was undertaken. New chiral acyclic diaminocarbenes were also developed and tested along side new C3-symmetric phosphite ligands in an asymmetric intramolecular hydroamination of allenes. Structure activity correlations were developed for the potential use in further rational ligand design. The synthesis of 6a,7-dihydro-5-amino-dibenzo[c,g]chromene derivatives via a gold-catalyzed domino reaction of alkynylbenzaldehydes in the presence of secondary amines was developed. These were sent to be screened for biological activity.
Book Synopsis Science of Synthesis N-Heterocyclic Carbenes in Catalytic Organic Synthesis by : Steven P. Nolan
Download or read book Science of Synthesis N-Heterocyclic Carbenes in Catalytic Organic Synthesis written by Steven P. Nolan and published by . This book was released on 2016-12 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt:
