Palladium-catalyzed methods for the aerobic oxidative coupling of alkenes and oxygen nucleophiles (e.g., water carboxylic acids) have been known nearly 50 years. The present account summarizes our development analogous amination reactions, including first intermolecular aza-Wacker reactions compatible with use unactivated alkenes. are initiated by intra- or aminopalladation alkene. resulting alkylpalladium(II) intermediate generally undergoes β-hydride elimination to produce enamides allylic...

A density functional theoretical (DFT) study (B3LYP) has been carried out on 20 organometallic complexes containing η5- and/or η3-coordinated cyclopentadienyl anions (Cp–) and 2,2′-bipyridine (bpy) ligand(s) at varying oxidation levels, i.e., as the neutral ligand (bpy0), π-radical monoanion (bpy•–)−, or diamagnetic dianion (bpy2–)2–. The molecular electronic structures of these species in their ground states and, some cases, first excited have calculated using broken-symmetry methodology....

The electron transfer series of complexes [Cr(tbpy)3]n(PF6)n (n = 3+, 2+, 1+, 0 (1–4)) has been synthesized and the molecular structures 1, 2, 3 have determined by single-crystal X-ray crystallography; structure 4 investigated using extended absorption fine (EXAFS) analysis. Magnetic susceptibility measurements (4–300 K) established an S 3/2 ground state for 1 1/2 3, 4. electrochemistry this in CH3CN solution exhibits three reversible one-electron waves. UV–vis/NIR spectra Cr K-edge (XAS)...

The molecular and electronic structures of the four members, [Cr(tpy)2](PF6)n (n = 3–0; complexes 1–4; tpy 2,2′:6′,2″-terpyridine), electron transfer series [Cr(tpy)2]n+ have been determined experimentally by single-crystal X-ray crystallography, their electro- magnetochemistry, following spectroscopies: absorption, absorption (XAS), paramagnetic resonance (EPR). monoanion this series, [Cr(tpy)2]1–, has prepared in situ reduction with KC8 its EPR spectrum recorded. 2, 3, 4, 5, 6, where...

Abstract The five‐membered electron‐transfer series [M(bpy) 3 ] n and [M(tpy) 2 (M = Fe, Ru; bpy 2,2′‐bipyridine, tpy 2,2′:6′,2″‐terpyridine) [Fe( t bpy) ( 4,4′‐di‐ tert ‐butyl‐2,2′‐bipyridine; 3+, 2+, 1+, 0, 1–) have been investigated the electronic structure of so called “low‐valent” complexes established by a combination electro‐ magnetochemistry, electron paramagnetic resonance (EPR) Mössbauer spectroscopy, X‐ray crystallography, DFT calculations. These are accessed reduction d 6 S 0...

Electrochemical transformations involve complex parameter interactions, ranging from universal chemistry variables such as solvent and reagents to specialist factors including electrode material current density. Hence, the development of a robust scale-independent electrochemical reaction can currently be challenge. High-throughput experimentation (HTE) is an enabling method for optimization robustness testing. Here we provide industrial academic perspective on state art combination HTE with...

Carbenes with a twist: A seven-membered N-heterocyclic carbene (NHC) ligand is prepared from an amidinium precursor, derived 2,2′-dinitrobiphenyl, and yields the NHC–PdII complex [PdCl(allyl)(NHC)] (see scheme). This framework exhibits tortional twist that results in axial symmetry. class can be readily modified attractive for future application asymmetric catalysis. Supporting information this article available on WWW under http://www.wiley-vch.de/contents/jc_2002/2005/z501522_s.pdf or...

Palladium(II) catalyzes the oxidative coupling of allyl tosylamides with butyl vinyl ether and various styrene derivatives to produce 2,4-substituted pyrrolidine products at room temperature. Molecular oxygen together a copper(II) cocatalyst mediates reoxidation palladium catalyst. The reactions substrates can be performed in an open flask ambient air as source O2. Several nontraditional cocatalysts, including catechol, cyclooctadiene, methyl acrylate, have beneficial effect on reactions.

The oxidation state of the chromium center in following compounds has been probed using a combination K-edge X-ray absorption spectroscopy and density functional theory: [Cr(phen)3][PF6]2 (1), [Cr(phen)3][PF6]3 (2), [CrCl2(tbpy)2] (3), [CrCl2(bpy)2]Cl0.38[PF6]0.62 (4), [Cr(TPP)(py)2] (5), [Cr(tBuNC)6][PF6]2 (6), [CrCl2(dmpe)2] (7), [Cr(Cp)2] (8), where phen is 1,10-phenanthroline, tbpy 4,4′-di-tert-butyl-2,2′-bipyridine, TPP2– doubly deprotonated 5,10,15,20-tetraphenylporphyrin. crystal...

Three's company: Iron(I) hydride complexes are presented (see picture; N blue, O red) that the first monomeric open-shell to be crystallographically verified as being three-coordinate at metal. Backbonding into diketiminate π* orbitals stabilizes low oxidation state. The FeH bonding has been analyzed using electron-nuclear double resonance (ENDOR).

A chiral seven-membered N-heterocyclic carbene (NHC) has been synthesized from its phenol adduct (NHC-HOPh) by a novel base-induced α-elimination method, and donor strength determined the IR stretching frequencies of NHC-Rh(CO)2Cl complex.

The first examples of iron(I) sulfide complexes are presented, in contrast with the +2 and +3 oxidation states that well-known synthetic biological systems. Spectroscopic computational studies show a high-spin d7 configuration at metal. Alkali metal cations play key role supporting unusually low state.

Metal(H2O2) complexes have been implicated in kinetic and computational studies but never observed. Accordingly, H2O2 has described as a very weak ligand. We report the first metal(H2O2) adduct, which is made possible by incorporating intramolecular hydrogen-bonding interactions with bound H2O2. This Zn(II)(H2O2) complex decays solution second-order process that slow enough to enable characterization of this species X-ray crystallography. speaks intermediacy adducts chemistry biology opens...

O2-derived CunO2 adducts are attractive targets for aerobic oxidation catalysis because of their remarkable reactivity, but the supporting ligand limits catalytic turnover. We report that tBu3tacn (1,4,7-tri-tert-butyl-1,4,7-triazacyclononane) supports a dicopper(II) μ-η2:η2-peroxo species with highest solution stability outside an enzyme. Decomposition this proceeds without ligand. Additive-free reactions at or above room temperature described, highlighting potential oxidatively robust...

Palladium-catalyzed directed arylation of 2,2′-diacetamidobiaryls with aryl iodides provides efficient access to chiral ortho-substituted biaryl diamines. Aryl para- and meta-substituents are tolerated. Deprotection the acetyl groups under basic conditions furnishes free diamines, which should find broad utility in asymmetric catalysis.

M(H2 O2 ) adducts have been postulated as intermediates in biological and industrial processes; however, only one observable adduct has reported, where M is redox-inactive zinc. Herein, direct solution-phase detection of an with a redox-active metal, cobalt(II), described. This Co(II) (H2 compound made by incorporating second-sphere hydrogen-bonding interactions between bound H2 the supporting ligand, trianionic trisulfonamido ligand. Thermodynamics binding decay kinetics species are...

The first synthesis of 1,4,7-tri-tert-butyl-1,4,7-triazacyclononane ((t)Bu3tacn) and its adamantyl analog Ad3tacn are described. Cr(II), Mn(II), Fe(II), Co(II), Ni(II), Cu(I) compounds (t)Bu3tacn reported: the steric properties this ligand enforce four-coordinate geometries except in case five-coordinate enabling design pseudotetrahedral bearing tridentate redox-inert ancillary ligand.

Here, we report the design and application of an electrochemical flow cell that provides excellent mixing enables high current densities on research-relevant scales (≤1 g, up to 10 g scale). The design, embedding a turbulence promoter cooling layers, as well pressure stability, allows use tool for efficient high-throughput synthesis applications. performance was demonstrated reaction conditions screening material production (436 mmol scale) with density 1000 mA/cm2 in oxidative...

Incorporating radical ligands into metal complexes is one of the emerging trends in design single-molecule magnets (SMMs). While significant effort has been expended to generate multinuclear transition metal-based SMMs with bridging ligands, less attention paid mononuclear metal–radical SMMs. Herein, we describe first α-diiminato radical-containing SMM, namely, [κ2-PhTttBu]Fe(AdNCHCHNAd) (1), and its analogue [κ2-PhTttBu]Fe(CyNCHCHNCy) (2) (PhTttBu = phenyltris(tert-butylthiomethyl)borate,...

Aller guten Dinge sind drei: Die vorgestellten Eisen(I)-hydridkomplexe (siehe Bild; N blau, O rot) die ersten monomeren offenschaligen Hydridkomplexe mit kristallographisch bestätigter Dreifachkoordination am Metallzentrum. Rückbindung in Diketiminat-π*-Orbitale stabilisiert niedrige Oxidationsstufe. Fe-H-Bindung wurde ENDOR-Spektroskopie analysiert.

Adducts of hydrogen peroxide and transition metals have been implicated as intermediates in biological industrial processes but only recently observed. Therefore, knowledge how interacts with is extremely limited. Herein, we report the synthesis H2O2 complexes cobalt, nickel, copper supported by sulfonamido ligands second-sphere bonding. Binding constant decay kinetics are reported for four new M(H2O2) adducts, providing a foundation future studies coordination oxidation catalysis.

The synthesis of 1,4‐di‐ tert ‐butyl‐7‐R‐1,4,7‐triazacyclononane ( t Bu 2 Rtacn) derivatives through a “crab‐like” cyclization is reported. ‐butyl groups were cleavable with concentrated hydrochloric acid, allowing for facile and convenient the HCl salt H 3 tacn most direct route to its industrially relevant binucleating N ‐ethylene bridged derivative, 4 dtne. In addition, chiral both one two stereocenters in non‐annulet, alpha‐N positions

Carbene mit einem „Dreh“: Ein siebengliedriges N-heterocyclisches Carben (NHC) als Ligand wurde aus einer von 2,2′-Dinitrobiphenyl abgeleiteten Amidiniumvorstufe hergestellt und lieferte den NHC-PdII-Komplex [PdCl(Allyl)(NHC)] (siehe Schema). Das Carbengerüst ist verdrillt, sodass es eine axiale Symmetrie zeigt. Diese Ligandenklasse lässt sich einfach modifizieren für künftige Anwendungen in der asymmetrischen Katalyse attraktiv.