Modes of Cooperative Effects in Dinuclear Complexes
- 2023
- Book
- Editor
- Philippe Kalck
- Book Series
- Topics in Organometallic Chemistry
- Publisher
- Springer International Publishing
About this book
This book presents recent advances in dinuclear complexes in which the metal-metal cooperative effect operates for obtaining substrate activation and high performance catalysts. Catalysis continues to be a fast expanding area to design efficient tools in synthesis and in industrial chemistry. It allows performing syntheses with short reaction times, atom economy, reduced consumption of energy and loss of reagents, and low level of wastes. Dinuclear complexes are known to be more efficient than the mononuclear analogues for the reaction rates and the selectivities. This book analyses the latest research, focusing on the key concepts, in building and using these dinuclear complexes. The book is aimed at researchers, graduate students and chemists at all levels in academia and industry.
Advertisement
Table of Contents
-
Frontmatter
-
Dinuclear Reactivity of One Metal Exalted by the Second One
Zoraida Freixa, Piet W. N. M. van Leeuwen, Philippe KalckThe chapter 'Dinuclear Reactivity of One Metal Exalted by the Second One' delves into the enhanced reactivity of dinuclear complexes in coordination chemistry. It focuses on the cooperative effect between two metal centers, where one metal center's reactivity is influenced by the second metal center, either through electronic effects or steric hindrance. The text discusses various types of reactions, including oxidative addition, migratory insertion, and reductive elimination, emphasizing the role of electronic and steric effects in these processes. The chapter also compares the reactivity of mononuclear and bimetallic complexes, highlighting the unique properties and mechanisms of dinuclear complexes. Theoretical calculations and experimental data are used to support the discussion, providing a comprehensive understanding of the reactivity and mechanisms involved in these complex systems.AI Generated
This summary of the content was generated with the help of AI.
AbstractThis chapter is devoted to the coordination sphere of the two metals of a dinuclear framework for which the reactivity of one metal center is exalted by the second one. Kinetic studies and theoretical calculations are efficient tools nowadays to ascertain that along the catalytic cycle, bimetallic species are operating in the various steps converting the substrate. Bimetallic coordination complexes are described, in which the nature of the bridging ligand plays an essential role, as their mutual steric and electronic influences are determined by the distance and orientation of the two metal centers. By many ways, one metal can influence the reactivity of a neighboring metal both in stoichiometric and catalytic reactions. The three elementary steps of oxidative addition, migratory insertion, and reductive elimination are analyzed in the light of the cooperative effect induced by the second metal center exalting the reactivity. The electronic effects played by the ligands of the coordination sphere appear essential, but in some examples, steric effects add a supplementary influence, which may result in an increased selectivity. The tug-in effect of one metal on the other one, especially in heterodinuclear species, can allow tuning the reactivity through an appropriate adjustment of the distance between the two metal centers and a Lewis acid functionality. These concepts can be extended to dinuclear species bonded to a surface. Of course, much progress is still necessary to anticipate the right way to design the multidentate ligands, which scaffold a dinuclear entity for a given stoichiometric or catalytic reaction. -
Chemical Transformations in Heterobimetallic Complexes Facilitated by the Second Coordination Sphere
R. Malcolm Charles III, Timothy P. BrewsterThis chapter delves into the fascinating world of heterobimetallic complexes, focusing on those where the two metal centers are not directly bound but interact through the second coordination sphere. It begins by categorizing these complexes into those with direct and indirect electronic modulation. The text explores various examples of stoichiometric bond activations, including cooperative and non-cooperative systems, and highlights how these complexes can achieve unique reactivity patterns. The chapter then transitions to discussing the catalytic applications of these complexes, showcasing their potential in polymerization, C-H functionalization, and emerging switchable systems. The final section introduces the concept of switchable catalysis, demonstrating how changes in the oxidation state or cation presence can control catalytic activity. This chapter is a must-read for those interested in the cutting-edge research on bimetallic complexes and their applications in catalysis.AI Generated
This summary of the content was generated with the help of AI.
AbstractThis chapter is dedicated to heterobimetallic complexes in which the two metal centers are not directly bound. Complexes are described in which the second metal resides in the second coordination sphere of the first metal and enables bond activation processes via synergistic activity with the first metal that are not available to the corresponding monometallic complexes. Both stoichiometric and catalytic bond activations are analyzed in the light of the type of reactions (e.g., H2 activation, polymerization, etc.). Both steric and electronic effects appear to play significant roles in many cases, and as such, they are examined when applicable. Indeed, spatial proximity between the two metal centers as well as electronic environment can allow for modification and tuning of reactivity. This realization has led to the development of switchable catalytic systems which are highlighted and discussed in terms of how they are manipulated (e.g., redox-switchable systems and cation-responsive systems). While significant progress has been made toward furthering our collective understanding of the behavior of these types of heterobimetallic complexes, this area is still ripe for future development. Additional systematic work is necessary to continue to push this area of chemistry forward. -
Role of a Redox-Active Ligand Close to a Dinuclear Activating Framework
Catherine Elleouet, François Y. Pétillon, Philippe SchollhammerThe chapter discusses the significance of redox-active ligands in dinuclear metal complexes, particularly those inspired by hydrogenases. It covers the integration of such ligands into bimetallic systems, focusing on their impact on catalytic activity and molecular activation. The text explores various types of redox ligands, including nitrosyl, phosphole, and nitrogen-based ligands, and their effects on the electronic properties and reactivity of dinuclear complexes. It also highlights the importance of electronic communication between the redox ligand and the metal centers for optimal catalytic performance. Additionally, the chapter provides insights into the design and synthesis of efficient catalysts, drawing parallels with natural systems like hydrogenases. This comprehensive overview offers valuable insights for researchers and professionals in the field of catalysis and inorganic chemistry.AI Generated
This summary of the content was generated with the help of AI.
AbstractThe main advances, over the last two decades, on dinuclear complexes featuring a redox-active ligand close to the bimetallic core are presented in this chapter. At the end of the nineties, the discovery of the structure of the active site of [FeFe]-hydrogenases has led to a revival of the chemistry of dithiolato/bis-thiolato bridged carbonyl di-iron complexes with the aim of understanding the functioning, at the molecular level, of this family of metallo-enzymes and to reproduce their activity towards the reversible H+/H2 conversion. The progress in the knowledge of the H-cluster reveals that its high activity is due to an efficient and subtle Nature’s engineering that involves a dinuclear activating framework and its cooperativity with redox-active ligand and proton-relay. If initially the development of this chemistry has been centred on the preparation of rudimentary di-iron compounds in order to study their ability to reduce protons electrochemically or photochemically, more sophisticated systems with a relay of protons, for promoting proton transfers, have rapidly emerged. Paradoxically, it is only quite recently that an increasing number of derivatives incorporating a redox-active ligand has been elaborated. To date, there are only a few di-iron compounds capable of reproducing H-cluster activity. These researches are still ongoing and they have contributed to develop the chemistry of dinuclear complexes with redox ligands.The first part of this chapter is dedicated to the advances in this di-iron bio-inspired chemistry, which has led to consider the combination of carbonyl di-iron platforms with a large series of redox ligands and the different ways for introducing them near the di-iron core. Examples of hetero-bimetallic [NiFe] species featuring a redox group, considered as models of the [NiFe]-hydrogenases, are also presented.Considering the renewal of the interest in using bimetallic systems for molecular activation in order to develop novel catalytic processes, the second part of this chapter presents selected examples of bimetallic derivatives featuring chelating redox-active ligands. Their properties/activities, often original or unexpected, in connection with the presence of the redox-active ligand in the coordination sphere of a dinuclear framework, are described. These results, even if their presentation in this chapter may appear somewhat scattered, demonstrate that the combination of “non-innocent” ligands (redox-active in this chapter but also proton-responsive) with dinuclear sites offers interesting perspectives in the field of molecular activation with transition metal complexes. -
Dinuclear Reactivity Between the Two Metal Centers
Laurent Maron, Philippe KalckThe chapter delves into the intricate world of dinuclear reactivity, where two metal centers cooperate to activate molecules. It begins by discussing the importance of cooperative effects between metal centers, which can enhance reactivity and selectivity compared to mononuclear complexes. The focus then shifts to the activation of molecules by homo- or hetero-bimetallic frameworks, highlighting the role of the coordination sphere in adjusting electron density and maintaining steric effects. The chapter also explores the mechanisms of dinuclear complexes containing adapted ligands for 1-electron reactions, including the absence of bridging ligands and the use of redox-active ligands. Notable examples include the Pauson–Khand reaction and the trimerization of alkynes on di-cobalt complexes. The text concludes by emphasizing the significance of suitable ligands for maintaining the right distance between metal centers and accommodating electronic effects and structural changes during catalytic steps. This chapter is a must-read for those seeking a deep understanding of dinuclear reactivity and the design of effective catalysts.AI Generated
This summary of the content was generated with the help of AI.
AbstractIn the field of metal-mediated selective and easier organic reactions, the present chapter focuses on the activation of at least one main step in the cleft of a dinuclear platform, in which a 1e-1e process occurs. This contribution emphasizes on the concepts that govern the conception of the coordination sphere in order to maintain the two metal centers at the right distance and which plays a central role in the electronic and steric effects. An analysis is done on systems operating in the absence of bridging ligands, particularly for the action of alkynes. A second part is devoted to the presence of ligands, which do not play a significant redox role. A third part concerns the use of redox-active bridging ligands. Many spectrometric characterizations, crystal structures, and theoretical calculations allow focusing this search on the main features that govern the reactivity of one metal center or the simultaneous two metal centers in the activation, selectivity, as well as original reactivity of a reactant or an intermediate in a catalytic step. -
Magnetism in Binuclear Compounds: Theoretical Insights
Rémi Maurice, Talal Mallah, Nathalie GuihéryThe chapter 'Magnetism in Binuclear Compounds: Theoretical Insights' delves into the remarkable properties of matter, such as magnetism, magnetoresistive effects, and molecular bistability, which offer promising technological applications. It focuses on the theoretical understanding of magnetic properties in binuclear complexes, emphasizing the role of exchange coupling and anisotropic interactions. The text introduces model Hamiltonians and discusses their extraction from theoretical calculations, highlighting the importance of accounting for relativistic effects and dynamic electron correlation. Practical examples and comparisons with experimental data are provided to illustrate the effectiveness of these theoretical methods. The chapter also explores the challenges and future directions in the study of magnetic interactions in binuclear compounds, making it a valuable resource for specialists in the field.AI Generated
This summary of the content was generated with the help of AI.
AbstractThis chapter is devoted to theoretical calculations aimed at determining the electronic structure of binuclear complexes, including isotropic and anisotropic interactions in both the strong and in the weak-exchange coupling limits. The theory of effective Hamiltonians is used to extract magnetic anisotropy terms in various regimes and in particular those for which the giant-spin approximation holds. While only a second-rank symmetric tensor is necessary to describe the zero-field splitting in centrosymmetric compounds with a single electron on each metal ion, a 4-rank tensor must also be introduced to describe the anisotropic exchange in the case of two unpaired electrons per metal ion. The magnitude of these additional interactions was found to be larger than those of the well admitted 2-rank tensor. Even though, the magnetic anisotropy of binuclear complexes can often be predicted from the knowledge of the local anisotropy of its mononuclear constituents, the large magnitude of the 4-rank tensor makes theoretical calculations important if not mandatory to rationalize experimental results on firm grounds in systems where anisotropic binuclear interactions are important.
- Title
- Modes of Cooperative Effects in Dinuclear Complexes
- Editor
-
Philippe Kalck
- Copyright Year
- 2023
- Publisher
- Springer International Publishing
- Electronic ISBN
- 978-3-031-32250-1
- Print ISBN
- 978-3-031-32249-5
- DOI
- https://doi.org/10.1007/978-3-031-32250-1
Accessibility information for this book is coming soon. We're working to make it available as quickly as possible. Thank you for your patience.
