A5077045901- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Crystallography and molecular interactions
- Organometallic Complex Synthesis and Catalysis
- Asymmetric Hydrogenation and Catalysis
- Organoboron and organosilicon chemistry
- Catalytic Cross-Coupling Reactions
- Catalytic C–H Functionalization Methods
- Synthesis and characterization of novel inorganic/organometallic compounds
- Coordination Chemistry and Organometallics
- Boron Compounds in Chemistry
- Magnetism in coordination complexes
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Synthetic Organic Chemistry Methods
- Metal-Organic Frameworks: Synthesis and Applications
- Oxidative Organic Chemistry Reactions
- Metal complexes synthesis and properties
- Hydrogen Storage and Materials
- Carbon dioxide utilization in catalysis
- Organophosphorus compounds synthesis
- Crystal structures of chemical compounds
- Asymmetric Synthesis and Catalysis
- Synthesis and Catalytic Reactions
- Chemical Synthesis and Analysis
- Organometallic Compounds Synthesis and Characterization
University of Bristol
2010-2020
O2 Czech Republic (Czechia)
2020
Heriot-Watt University Malaysia
2020
Heriot-Watt University
2019
At Bristol
2013-2016
AstraZeneca (Sweden)
2012
Universität Innsbruck
2004-2011
University of Oxford
2010
University of Łódź
2010
Lodz University of Technology
2010
The extension of the frustrated Lewis pair (FLP) concept to transition series with cationic zirconocene-phosphinoaryloxide complexes is demonstrated. Such mimic reactivity main group FLPs in reactions such as heterolytic hydrogen cleavage, CO(2) activation, olefin and alkyne addition, ring-opening tetrahydrofuran. interplay between sterics electronics shown have an important role determining these compounds particular. Zr-H species generated from activation undergo insertion both CO....
Taming the beast: Unprecedented selectivity of over 94 % at good (20 %+) conversion was observed for upgrade ethanol to advanced biofuel 1-butanol with a ruthenium diphosphine catalyst (see picture; P orange, Ru blue). Preliminary mechanistic studies indicate that control notoriously uncontrolled acetaldehyde aldol condensation is critical high selectivity, and evidence found an on-metal step. As service our authors readers, this journal provides supporting information supplied by authors....
The cationic zirconocene-phosphinoaryloxide complexes [Cp(2)ZrOC(6)H(4)P(t-Bu)(2)][B(C(6)F(5))(4)] (3) and [Cp*(2)ZrOC(6)H(4)P(t-Bu)(2)][B(C(6)F(5))(4)] (4) were synthesized by the reaction of Cp(2)ZrMe(2) or Cp*(2)ZrMe(2) with 2-(diphenylphosphino)phenol followed protonation [2,6-di-tert-butylpyridinium][B(C(6)F(5))(4)]. Compound 3 exhibits a Zr-P bond, whereas bulkier Cp* derivative 4 was isolated as chlorobenzene adduct without this interaction. These compounds can be described...
Reducing the load: A facile palladium-catalyzed ortho-selective bromination and chlorination of anilides occurs under aerobic conditions at room temperature when N-halosuccinimides (NXS) are used in presence p-toluenesulfonic acid (PTSA). The orthopalladated PTSA complex is not only catalytically competent but also undergoes a reductive process to yield an unusual PdI–PdII tetramer (see structure; Pd green, O red, S yellow, C gray). Detailed facts importance specialist readers published as...
Herein we demonstrate both the importance of Fe(I) in Negishi cross-coupling reactions with arylzinc reagents and isolation catalytically competent intermediates. These complexes, [FeX(dpbz)2] [X = 4-tolyl (7), Cl (8a), Br (8b); dpbz 1,2-bis(diphenylphosphino)benzene], were characterized by crystallography tested for activity representative reactions. The complexes are low-spin no significant spin density on ligands. While complex 8b shows performance consistent an on-cycle intermediate, it...
The reactions of iron chlorides with mesityl Grignard reagents and tetramethylethylenediamine (TMEDA) under catalytically relevant conditions tend to yield the homoleptic "ate" complex [Fe(mes)3 ](-) (mes=mesityl) rather than adducts diamine, it is this ate that accounts for catalytic activity. Both related [Fe(Bn)3 (Bn=benzyl) react faster representative electrophiles equivalent neutral [FeR2 (TMEDA)] complexes. Fe(I) species are observed both benzyl smaller aryl reagents. X-ray structures...
We report the first insertion step at a metal center for catalytic dehydropolymerization of H(3)B·NMeH(2) to form simplest oligomeric species, H(3)B·NMeHBH(2)·NMeH(2), by addition 1 equiv [Ir(PCy(3))(2)(H)(2)(η(2)-H(3)B·NMeH(2))][BAr(F)(4)] give [Ir(PCy(3))(2)(H)(2)(η(2)-H(3)B·NMeHBH(2)·NMeH(2))][BAr(F)(4)]. This reaction is also formation free linear diborazane, but this best obtained an alternative stoichiometric synthesis.
Stick or twist: By introducing steric hindrance at the nitrogen atom, stable linear amides bearing an electron-withdrawing α-substituent (Z=Ar, PhSO2, P(O)(OR)2, CN, CO2R) can be induced to undergo solvolysis and substitution reactions through elimination–addition mechanism (see picture). Key this process is a low barrier rotation around amide bond Z. Detailed facts of importance specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not copy-edited...
The chiral sulfide, isothiocineole, has been synthesized in one step from elemental sulfur, γ-terpinene, and limonene 61% yield. A mechanism involving radical intermediates for this reaction is proposed based on experimental evidence. application of isothiocineole to the asymmetric epoxidation aldehydes aziridination imines described. Excellent enantioselectivities diastereoselectivities have obtained over a wide range aromatic, aliphatic, α,β-unsaturated using simple protocols. In...
Iron phosphine complexes prove to be good precatalysts for the cross-coupling of alkyl, benzyl, and allyl halides with not only aryl triorganoborate salts but also related aluminum-, gallium-, indium-, thallium-based nucleophiles. Mechanistic studies revealed that while Fe(I) can accessed on catalytically relevant time scales, lower average oxidation states are formed fast enough catalysis. EPR spectroscopic reveal presence bis(diphosphine)iron(I) in representative catalytic reactions...
Crystal engineering has become an established part in various segments of industrial research. The toolbox crystal not only offers design strategies for performance chemicals and characterization tools active ingredients but also helps to provide fundamental concepts understanding the principles behind formation properties organic solids. In this highlight examples are given application during different phases development products, e.g. pigments, dyes, agrochemicals drugs. addition, future...
The addition of H(2) across a transition metal-borane bond is reported for the first time providing mechanism recharging borane functional groups to borohydride.
Man braucht nur den richtigen Bis(s)! Eisenkatalysatoren auf Basis des leicht zugänglichen Liganden Bis(diphenylphosphanyl)ethan waren früher wenig erfolgreich in Fe-katalysierten Kreuzkupplungen. Es zeigt sich aber, dass dies nicht von einer inhärent schlechten Leistungsfähigkeit herrührt, sondern vielmehr der erforderlichen Bildung eines Bis(chelat)-Komplexes vor oder während Entstehung aktiven FeI-Spezies.
Complexes of Group 4 metallocenes in the +3 oxidation state and amidoborane or phosphidoborane function as efficient precatalysts for dehydrocoupling/dehydrogenation amine-boranes, such Me(2) NH⋅BH(3). Such Ti(III) -amidoborane complexes are generated [Cp(2)Ti]-catalyzed amine-borane dehydrocoupling reactions, which diamagnetic M(II) M(IV) species have been previously postulated intermediates.
Abstract The catalyst loading is the key to control molecular weight of polymer in iron‐catalyzed dehydropolymerization phosphine–borane adducts. Studies showed that reaction proceeds through a chain‐growth coordination–insertion mechanism.
The synthesis of a range chiral palladium bis(phosphite) pincer complexes has been achieved via C-H activation the parent ligands and one formed shows good activity in catalytic allylation aldehydes.
The symmetrical diphosphanes R2P−PR2 {where R = Ph (1a), Cy (1b), or But (1c)} are made by the reaction of R2PLi with R2PCl. unsymmetrical R2P−PR'2 and R' (2a); o-Tol (2b); (2c); (2d); (2e)} R2P(BH3)Li R'2PCl followed deprotection Et2NH. Diphosphanes 1a,b 2a−d react ZC⋮CZ (Z CO2Me) to give corresponding R2PCZCZPR2 (3a,b) R2PCZCZPR'2 (4a−d). 2a,b HC⋮CZ R2PCHCZPR2 (5a,b). A mechanism is proposed that accounts for cis stereospecificity regioselectivity these diphosphinations. Treatment...
Oxidative activation of a B–H bond coordinated scorpionate ligand provides an unprecedented route to rhodaboratranes.
Complexes of the type [(diphosphine)Cr(CO)4] (diphosphine = Ph2PN(iPr)PPh2, Ar2PN(Me)PAr2 or Ar2PCH2PAr2 (Ar 2-C6H4(MeO)) have been synthesised. In solid state, these complexes show tight phosphine bite angles in range 67.82(4)° to 71.52(5)° and nitrogen atom N,N-bis(diarylphophino)amine ligands adopts an almost planar (sp2) geometry. All are readily oxidised electrochemically chemically corresponding Cr(I) species. There is no evidence for coordination pendant ether group derivatives with...
Palladium-catalysed dearomatisation reactions allow access to a previously unknown class of indoloindole heterocycle: 5,10b-dihydroindolo[2,3-b]indoles. The highly reactive nature these compounds is demonstrated by their facile with water and hydride, alkyl, aryl allyl-based organometallic nucleophiles.
The synthesis of the salt 3 and metallo-organic framework (MOF) [{(4,4(')-bipy)CoBr(2)}(n)] 4 by a range solid state (mechanochemical thermochemical) solution methods is reported; they are isostructural with their respective chloride analogues 1 2. can be interconverted means HBr elimination absorption. Single phases controlled composition general formula [4,4(')-H(2)bipy][CoBr(4-x)Cl(x)] 5(x) may prepared from 2 solid--gas reactions involving or HCl respectively. Crystalline single phase...
Abstract The ability of trialkyl Group 14 triflates in combination with amine and pyridine bases to dehydrogenate amine– phosphane–borane adducts has been investigated. By using multinuclear NMR spectroscopy, it shown that Me 2 NH · BH 3 ( 11 ) is efficiently converted [Me N–BH ] 12 by the so‐called “frustrated Lewis pair” (FLP) n Bu SnOTf 4 , – OTf = OSO CF 2,2,6,6‐tetramethylpiperidine 6 ). Within scope study, exchange acid effects rate dehydrogenation order: > SiOTf Et Exchange base...
Eine einfache Pd-katalysierte ortho-selektive Bromierung und Chlorierung von Aniliden gelingt unter aeroben Bedingungen bei Raumtemperatur, wenn N-Halogensuccinimide (NXS) in Gegenwart p-Toluolsulfonsäure (PTSA) eingesetzt werden. Der orthopalladierte PTSA-Komplex ist nicht nur katalytisch aktiv, sondern geht auch einen reduktiven Prozess Bildung eines ungewöhnlichen PdI-PdII-Tetramers ein (siehe Struktur; Pd grün, O rot, S gelb, C grau). Detailed facts of importance to specialist readers...
A cubic cage complex assembled from twelve bis-bidentate ligands and eight Co(II) ions provides a cavity that selectively recognises binds coumarin in MeCN solution. The portals are large enough to allow guest exchange, but small provide kinetic trap; the paramagnetism facilitates detailed NMR analysis.