Concluding remarks for “Mechanistic Processes in Organometallic Chemistry”: the importance of a multidisciplinary approach
The Faraday Discussions meeting on Mechanistic Processes in Organometallic Chemistry was a brilliant occasion to assemble chemists from diverse sub-disciplines to discuss the progress and limitations of the study of reaction mechanisms using organometallic systems for stoichiometric or catalytic reactions.
The effect of coordination of alkanes, Xe and CO2 (η1-OCO) on changes in spin state and reactivity in organometallic chemistry: a combined experimental and theoretical study of the photochemistry of CpMn(CO)3
A study is presented of ligand addition reactions of the fragment 3CpMn(CO)2 formed upon photolysis of CpMn(CO)3.
Platinum-mediated B–H methoxylation of bis(pyrazolyl)borate
Mechanistic investigations into the role of Pt(II) in mediating methoxylation of B–H fragments of bis(pyrazolyl)borate.
Physical insights into mechanistic processes in organometallic chemistry: an introduction
Mechanistic studies of late transition metal hydride homogeneous catalysts – 3d versus 4d metals.
Elucidating cation effects in homogeneously catalyzed formic acid dehydrogenation
In this work, we use density functional theory based molecular dynamics with an explicit description of methanol solvent to study the effect of cations on formic acid dehydrogenation catalyzed by a ruthenium PNP pincer complex (RuPNP).
Direct experimental evaluation of ligand-induced backbonding in nickel metallacyclic complexes
The details of ligand-induced backbonding in nickel diphosphine π complexes are explored using nickel L-edge (3d←2p) X-ray absorption spectroscopy as a means of quantifying the degree of backbonding derived from direct Ni 3d donation into the π ligand.
Activation of tetrafluoropropenes by rhodium(I) germyl and silyl complexes
The activation of tetrafluoropropenes at rhodium silyl and germyl complexes revealed various reaction pathways such as the generation of organic derivatives of the substrate and a rhodium fluorido complex or the formation of rhodium vinyl complexes.
Hard X-ray spectroscopy: an exhaustive toolbox for mechanistic studies (?)
The hard X-ray spectroscopy methods XAS, valence-to-core XES and higher solution XANES offer unique insights into organometallic reaction mechanisms.
Kinetic analysis of bioorthogonal reaction mechanisms using Raman microscopy
Kinetic analysis of CuAAC and Glaser–Hay bioorthogonal reactions can be achieved with Raman microscopy using alkyne vibrations in the cell-silent region.
Revealing the reduction process of Cu(II) by sodium bis(trimethylsilyl)amide
Using XAS and EPR spectroscopy, we showed that sodium bis(trimethylsilyl)amide (NaHMDS) serving as an electron donor could reduce Cu(II) to an active Cu(I) species.
Kinetics of initiation of the third generation Grubbs metathesis catalyst: convergent associative and dissociative pathways
The monopyridyl form of the Grubbs III catalyst initiates rapidly, via both dissociative and associative pathways.
Catalyst design insights from modelling a titanium-catalyzed multicomponent reaction
Heteroleptic catalyst stability toward disproportionation was modelled based on ligand donor abilities, which is of critical importance in some catalyses.
The electrostatic potential as a descriptor for the protonation propensity in automated exploration of reaction mechanisms
We discuss the possibility of exploiting local minima of the molecular electrostatic potential for locating protonation sites in molecules in a fully automated manner.
Understanding electronic effects on carboxylate-assisted C–H activation at ruthenium: the importance of kinetic and thermodynamic control
C–H activation processes may show contradictory substituent effects depending on the reaction conditions: under kinetic control ligands with electron-releasing substituents are favoured, whereas the opposite trend is seen under thermodynamic control.
Direct dynamics analysis of the cationic Cp*(PMe3)Ir(CH3) methane C–H activation mechanism
Quasiclassical direct dynamics reveal a dynamical one-step organometallic mechanism for the σ-bond metathesis reaction between Cp*(PMe3)IrIII(CH3) and methane.
Insight into catalyst speciation and hydrogen co-evolution during enantioselective formic acid-driven transfer hydrogenation with bifunctional ruthenium complexes from multi-technique operando reaction monitoring
Operando spectroscopy shows a transition from dehydrogenation to hydrogen transfer during the reaction, and allows measuring optimal conditions for maximum rate and efficiency.
Suzuki–Miyaura coupling revisited: an integrated computational study
Computation is used to revisit the mechanism of the Suzuki–Miyaura coupling mechanism.
Isolation of a C3-metalated indolizine complex and a phosphonium ring-fused bicyclic metallafuran from the osmium-induced transformation of pyridine-tethered alkynes
Isolation of the C3-metalated indolizine and bicyclic osmafuran complexes revealed the intermediacy of metal–vinylidene species regarding [Os(dppm)2Cl]+-mediated alkyne transformations.
FBpin and its adducts and their role in catalytic borylations
Fluoride ion plays a dual role in both metal-catalysed and metal-free borylation reactions by activating B2pin2 and trapping Lewis acidic FBpin.
Diruthenium complexes having a partially hydrogenated bipyridine ligand: plausible mechanism for the dehydrogenative coupling of pyridines at a diruthenium site
Diruthenium complexes containing a partially hydrogenated bipyridine ligand are synthesized, which undergo dehydrogenation leading to the elimination of bipyridine.
Towards measuring reactivity on micro-to-millisecond timescales with laser pump, NMR probe spectroscopy
We present a quantitative analysis of the timescales of reactivity that are accessible to a laser pump, NMR probe spectroscopy method using para-hydrogen induced polarisation (PHIP) and identify three kinetic regimes: fast, intermediate and slow.
Benefit of a hemilabile ligand in deoxygenation of fatty acids to 1-alkenes
DFT calculations show how the hemilability of DPEphos facilitates the Pd-DPEphos-catalysed decarbonylative dehydration of fatty acids to α-olefins.
Metal–ligand cooperative C–O bond cleavage of propargylic alcohol with protic pyrazole complexes of ruthenium
Protic pyrazole–ruthenium complexes promoted the C–O and C–H bond cleavage of a propargylic alcohol through metal–ligand cooperation.
Bambusurils as a mechanistic tool for probing anion effects
We present bambusurils, macrocycles which strongly bind anions of different sizes, as a mechanistic tool to probe counter ion effects in metal catalysis.
Investigations into the mechanism of copper-mediated Glaser–Hay couplings using electrochemical techniques
Electrochemical control has been utilised to facilitate the generation and identification of a Cu(I) complex (‘Jagner’s complex’) capable of promoting Glaser–Hay coupling reactions.
About this collection
We are delighted to share with you a selection of the papers which will be presented at our Faraday Discussion on Mechanistic processes in organometallic chemistry taking place in York, UK in September 2019. More information about the event may be found here: http://rsc.li/organometallic-fd2019. Additional articles will be added to the collection as they are published. The final versions of all the articles presented and a record of the live discussions will be published after the event.
Organometallic chemistry underpins the majority of homogeneous catalysis, which is used in a range of areas from the multi-tonne-scale synthesis of polymers to the discovery and preparation of high-value molecules such as pharmaceuticals and agrochemicals. The development and/or optimisation of many of these catalytic applications crucially depends on the discovery and understanding of mechanistic processes in organometallic chemistry. As such, mechanistic investigations have played a key role in the field of organometallic chemistry since its early days. The recent and rapid growth in transition-metal catalysed organic reactions, where fundamental mechanistic insight is frequently lagging behind synthetic developments, emphasises their contemporary importance. In addition, there have been many significant developments recently in the physical methods that can be used to gain mechanistic understanding in organometallic chemistry (e.g. NMR spectroscopic developments such as new hyperpolarisation techniques, in-situ IR for reaction monitoring, novel methodologies for kinetic analysis and novel computational approaches).
The Discussion will provide a focussed meeting on mechanistic studies coupled with novel experimental and computational methods that will bring together experts with a wide range of interests and backgrounds, including those developing new physical methods for mechanistic investigations and potential end users of these methods.