A series of homogeneous iridium bis(N-heterocyclic carbene) catalysts are active for three transformations involving dehydrogenative methanol activation: acceptorless dehydrogenation, transfer hydrogenation, and amine monoalkylation. The dehydrogenation reaction requires base, yielding formate carbonate, as well 2–3 equivalents H2. Of the few systems known this reaction, our tolerate air employ simple ligands. Transfer hydrogenation ketones imines from is also possible. Finally,...

A family of iron complexes PNP pincer ligands are active catalysts for the conversion glycerol to lactic acid with high activity and selectivity. These also catalyse transfer hydrogenation reactions using as hydrogen source.

Water-oxidation catalysis is a critical bottleneck in the direct generation of solar fuels by artificial photosynthesis. Catalytic oxidation difficult substrates such as water requires harsh conditions, so ligand must be designed both to stabilize high states metal center and strenuously resist degradation. Typical choices either lack sufficient electron donor power or fail stand up oxidizing conditions. Our research on Ir-based water-oxidation catalysts (WOCs) has led us identify ligand,...

Homogeneous iridium catalysts are reported for the highly efficient and selective conversion of polyols to hydrogen gas lactic acid.

Chemical and electrochemical oxidation or reduction of our recently reported Ir(IV,IV) mono-μ-oxo dimers results in the formation fully characterized Ir(IV,V) Ir(III,III) complexes. The are unprecedented exhibit remarkable stability under ambient conditions. This modest potential 0.99 V vs NHE is part attributed to complete charge delocalization across both Ir centers. Trends crystallographic bond lengths angles shed light on structural changes accompanying reduction. similarity these "blue...

[18F]-labeled aryl fluorides are widely used as radiotracers for positron emission tomography (PET) imaging. Aryl halides (ArX) particularly attractive precursors to these radiotracers, they readily available, inexpensive, and stable. However, date, the direct preparation of [18F]-aryl from remains limited SNAr reactions between highly activated ArX substrates K18F. This report describes an halide radiofluorination reaction in which C(sp2)–18F bond is formed via a copper-mediated pathway....

Abstract The title cluster, a deactivation product in the catalytic dehydrogenation of glycerol, was characterized by XRD, DFT calculations, HRMS, FTIR spectroscopy, and NMR spectroscopy. Experimental/computational studies located 14 H ligands, all 1 13 C{ H} resonances were assigned. structure contains an unprecedented Ir 6 core with two CO eight IMe ligands.

Sodium borohydride and a series of related borohydrides catalyze transition metal-free hydrosilylation variety CO CN functionalities under mild conditions. Importantly, many these reactions are possible using the cheap environmentally benign hydrosilane polymethylhydrosiloxane. A mechanism is proposed based on experimental computational results.

The highly active iridium "blue solution" chemical and electrochemical water oxidation catalyst obtained from Cp*IrL(OH) precursors (L = 2-pyridyl-2-propanoate) has been difficult to characterize as no crystal structure can be because of the multiplicity geometrical isomers present. Other data suggest complete loss Cp* ligand formation a LIr-O-IrL unit. We have now developed route series well-defined Ir(IV,IV) mono-μ-oxo dimers, containing closely related L2Ir-O-IrL2 Unlike catalyst, these...

This article describes a sequential Ir/Cu-mediated process for the meta-selective C–H radiofluorination of (hetero)arene substrates. In first step, Ir-catalyzed C(sp2)–H borylation affords (hetero)aryl pinacolboronate (BPin) esters. The intermediate organoboronates are then directly subjected to copper-mediated with [18F]tetrabutylammonium fluoride afford fluorine-18 labeled (hetero)arenes in high radiochemical yield and purity. entire is performed on benchtop without Schlenk or glovebox...

We describe facial and meridional isomers of [Rh(III)(pyalk)3], as well [Rh(IV)(pyalk)3](+) {pyalk =2-(2-pyridyl)-2-propanoate}, the first coordination complex in an N,O-donor environment to show a clean, reversible Rh(III/IV) redox couple have stable Rh(IV) form, which we characterize by EPR UV-visible spectroscopy X-ray crystallography. The unprecedented stability species is ascribed exceptional donor strength ligands, their oxidation resistance, geometry.

Abstract We have prepared and fully characterized two isomers of [Ir IV (dpyp) 2 ] (dpyp=meso‐2,4‐di(2‐pyridinyl)‐2,4‐pentanediolate). These complexes can cleanly oxidize to V + , which our knowledge represent the first mononuclear coordination Ir in an N,O‐donor environment. One isomer has been state, including by X‐ray crystallography, XPS, DFT calculations, all confirm metal‐centered oxidation. The unprecedented stability these is ascribed exceptional donor strength ligands, their...

This report describes a copper-mediated radiocyanation of aryl halides that is applicable to complex molecules. transformation tolerates an exceptionally wide range functional groups, including unprotected amino acids. As such, it enables the site-specific introduction [11C]CN into peptides at iodophenylalanine residue. The use diamine-ligated copper(I) mediator crucial for achieving high radiochemical yield under relatively mild conditions, thus limiting racemization and competing side...

Two unique Ir₄ clusters isolated during catalytic glycerol dehydrogenation, crystallized using aqueous and organic gel matrices displaying remarkable structural features are described.

An asymmetric synthesis of cis-1,2-diaryltetralin (2), a key chiral intermediate in the Vepdegestrant (1), an orally available PROTAC being evaluated for treatment ER+/HER2- breast cancer, is reported. Chirality initially introduced via catalytic enantioselective intramolecular Corey-Chaykovsky epoxidation utilizing isothiocineole, sulfide. Although several intermolecular epoxidations using sulfides have been reported, our approach represents unique variant. The subsequent introduction...

There is great interest in developing Mn water-splitting catalysts due to their low cost, abundance, and relevance the oxygen-evolving complex (OEC). Three ligands with highly donating pyridine alkoxide moieties, including 2-(pyridin-2-yl)propan-2-ol (pyalkH), 2,2'-(pyridine-2,6-diyl)bis(propan-2-ol) (py-dialkH2 ), 2-[(2,2'-bipyridin)-6-yl]propan-2-ol (bipy-alkH), have been screened for oxygen-evolution catalysis. Complexes ligand bipy-alkH were shown evolve O2 when driven by Oxone...

Abstract Dehydrogenation is a sustainable form of oxidation catalysis, as it avoids any primary oxidant and the waste that would accompany it. Homogeneous catalyst design for this reaction delicate: must have sufficient H 2 affinity to abstract two hydrogen atoms from substrate but not so much fail release them free . N‐Heterocyclic carbene (NHC) ligands achieve balancing act in series iridium catalysts based on Ir(IMe) motif (IMe=N,N′‐dimethylimidazol‐2‐ylidene). Catalyst also needs account...

We report a general method for the preparation and crystallization of highly oxidized metal complexes that are difficult to prepare handle by more conventional means. This improves typical bulk electrolysis conditions these reactive species substituting oxidation-prone organic electrolytes precipitants with oxidation-resistant compounds. Specifically, we find CsPF6 is an effective inert electrolyte in acetonitrile, appears have applicability electrochemical studies this solvent. Likewise,...

One ongoing challenge in the field of iridium-based water oxidation catalysts is to develop a molecular precatalyst affording well-defined homogeneous active species for catalysis. Our previous work by using organometallic precatalysts Cp*Ir(pyalk)OH and Ir(pyalk)(CO)2 (pyalk = (2-pyridyl)-2-propanolate) suggested μ-oxo-bridged Ir dimer as probable resting state, although structure remained elusive. During activation, ligands Cp* CO were found oxidatively degrade into acetic acid or other...

A series of novel polydentate N,O-donor ligands strongly favour formation polynuclear complexes.

Abstract We have prepared and fully characterized two isomers of [Ir IV (dpyp) 2 ] (dpyp=meso‐2,4‐di(2‐pyridinyl)‐2,4‐pentanediolate). These complexes can cleanly oxidize to V + , which our knowledge represent the first mononuclear coordination Ir in an N,O‐donor environment. One isomer has been state, including by X‐ray crystallography, XPS, DFT calculations, all confirm metal‐centered oxidation. The unprecedented stability these is ascribed exceptional donor strength ligands, their...