A5079306493- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Organometallic Complex Synthesis and Catalysis
- Crystallography and molecular interactions
- Synthesis and characterization of novel inorganic/organometallic compounds
- Coordination Chemistry and Organometallics
- Synthetic Organic Chemistry Methods
- Carbon dioxide utilization in catalysis
- Organoboron and organosilicon chemistry
- Asymmetric Hydrogenation and Catalysis
- biodegradable polymer synthesis and properties
- Inorganic Chemistry and Materials
- Metal complexes synthesis and properties
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Magnetism in coordination complexes
- Ferrocene Chemistry and Applications
- Catalytic Alkyne Reactions
- Metalloenzymes and iron-sulfur proteins
- Radioactive element chemistry and processing
- Boron Compounds in Chemistry
- Catalytic Cross-Coupling Reactions
- Hydrogen Storage and Materials
- Synthesis and Catalytic Reactions
- Fluorine in Organic Chemistry
- Crystal structures of chemical compounds
University of Oxford
2011-2021
Science Oxford
1991-2019
Oxfam
2014-2015
University of British Columbia
2015
Université de Montpellier
2004-2013
Centre National de la Recherche Scientifique
2000-2013
Institut Charles Gerhardt Montpellier
2006-2013
Monash University
2012
University College London
2012
Oxford Research Group
2008-2012
Simple two-coordinate acyclic silylenes, SiR(2), have hitherto been identified only as transient intermediates or thermally labile species. By making use of the strong σ-donor properties and high steric loading B(NDippCH)(2) substituent (Dipp = 2,6-(i)Pr(2)C(6)H(3)), an isolable monomeric species, Si{B(NDippCH)(2)}{N(SiMe(3))Dipp}, can be synthesized which is stable in solid state up to 130 °C. This silylene species undergoes facile oxidative addition reactions with dihydrogen (at...
This Account highlights aspects of the reactions and applications titanium imido complexes. Over past decade in particular, Ti=NR linkage has been shown to couple stoichiometrically with a variety unsaturated substrates including CO(2), carbodiimides, isocyanates, isocyanides, acetonitrile, phosphaalkynes, alkynes, alkenes, allenes. Especially recently, there much interest using imides as catalysts for hydroamination olefin polymerization. The advances these areas are also reviewed.
Tris(pyrazolyl)methanes are the neutral analogues of widely exploited and highly useful tris(pyrazolyl)hydroborates, yet by comparison with their boron based counterparts chemistry is underdeveloped. Recent breakthroughs in synthesis ring-substituted tris(pyrazolyl)methanes offer opportunity for development this promising class ligand. This review summarises current state coordination organometallic highlights areas which likely to occur.
Abstract Transition metal imido compounds having the general formula [(L) n M(NR)] [where (L) is a supporting ligand or set, and R typically alkyl aryl] have been known for nearly 50 years, during last two decades focus of considerable attention. Relatively recently their potential application in Ziegler–Natta polymerisation olefins has realised. In this contribution we review by transition compounds. A introduction to homogeneous olefin key aspects chemistry given, followed short...
Reaction of Na2O2NN' [H2O2NN' = (2-C5H4N)CH2N{2-HO-3,5-C6H2tBu2}2] with M(BH4)3(THF)3 afforded the dimeric, rare-earth borohydride compounds [M(O2NN')(μ-BH4)(THF)n]2 [M YIII, n 0.5 (1-Y); M NdIII, 1 (1-Nd); SmIII, 0 (1-Sm)]. For comparison chloride analogues [M(O2NN')(μ-Cl)(THF)n]2 (2-M; LaIII or 0; 1) and corresponding pyridine adducts [M(O2NN')(μ-X)(py)]2 [X BH4 (3-M) Cl (4-M); LaIII, SmIII] were prepared structurally characterized for 4-La. Compounds 1-M initiated ring-opening...
By employing strongly σ-donating boryl ancillary ligands, the oxidative addition of H2 to a single site Sn(II) system has been achieved for first time, generating (boryl)2SnH2. Similar chemistry can also be protic and hydridic E-H bonds (N-H/O-H, Si-H/B-H, respectively). In case ammonia (and water, albeit more slowly), shown followed by reductive elimination give an N- (or O-)borylated product. Thus, in stoichiometric fashion, redox-based bond cleavage/formation is demonstrated main group...
The synthesis and ring-opening polymerization (ROP) capability of bis(phenolate)amine-supported samarium borohydride amide complexes are reported, together with a DFT study. Reaction Na2O2NL (L = OMe, NMe2, py, or Pr) Sm(BH4)3(THF)3 gave the Sm(O2NL)(BH4)(THF) OMe (2), NMe2 (3), py (4)) Sm(O2NPr)(BH4)(THF)2 (5). Compounds 4 5 lost THF in vacuo, forming phenolate O-bridged dimers 1 6, respectively. H2O2NL Sm{N(SiHMe2)2}3(THF)2 formed monomeric Sm(O2NL){N(SiHMe2)2}(THF) (7), (8), (9))...
Si in sight: A one-pot, single-step synthesis of an acyclic silylsilylene, Si{Si(SiMe3)3}{N(SiMe3)Dipp} (Dipp=2,6-iPr2C6H3), from a silicon(IV) starting material is reported, together with evidence for mechanism involving alkali metal silylenoid intermediates.
The first cationic main group tetrahydroborate complexes are reported. [Ca(BH(4))(THF)(5)][BPh(4)] and the charge neutral (Tp((t)Bu,Me))Ca(BH(4))(THF) initiators for living ring opening polymerization of rac-lactide, latter producing PLA with high levels heterotactic enrichment. These represent a new class ROP metals.
Dicationic, zwitterionic and "conventional" yttrium compounds act as catalysts for the primary or secondary amine-initiated immortal ROP of rac-lactide; amine-terminated, highly heterotactic poly(rac-lactides) with narrow polydispersities well-controlled molecular weights are prepared in this manner.
The discovery of transition metal-catalysed polymerisation olefins in the 1950s by Ziegler and Natta was huge importance. Over last 30 years, interest homogenous has not only grown but changed focus from primarily studying metallocene complexes Group 4 to widespread exploration post-metallocene systems. This is a consequence extensive patenting catalyst systems, as well for general improvement polyolefin catalysis. plastics industry produces more than 107 tonnes polyethylene, polypropylene...
A general entry point to new titanium imido chemistry is gained via the readily prepared synthons [Ti(NR)Cl2(py)3] (R = But or aryl) and their homologues, from which straightforward metathesis reactions afford a wide range of derivatives. The structures, solution dynamics reactivity these compounds are reviewed.
Reaction of [Ln(CH(2)SiMe(3))(2)(THF)(n)][BPh(4)] (Ln = Sc, Y, Lu ; n 3, 4) with Li{B(NArCH)(2)}(THF)(2) (Ar 2,6-C(6)H(3)(i)Pr(2)) formed the first group 3 and lanthanide boryl compounds, Sc{B(NArCH)(2)}(CH(2)SiMe(3))(2)(THF) Ln{B(NArCH)(2)}(CH(2)SiMe(3))(2)(THF)(2) Lu), which contain two-center, two-electron Ln-B σ bonds. All these systems were crystallographically characterized. Density functional theory analysis bonding found it to be predominantly ionic, covalent character in σ-bonding HOMO.
The reaction of Sm{N(SiMe3)2}3 with the bis(phenol)amines H2O2NR (H2O2NR = RCH2CH2N(2-HO-3,5-C6H2tBu2)2; R OMe, NMe2 or Me) gave exclusively zwitterions Sm(O2NR)(HO2NR). For OMe these were efficient catalysts for ring-opening polymerisation ε-caprolactone and D,L-lactide a tendency to form cyclic esters; in contrast, no was observed Me.
The synthesis, structures, and ring-opening polymerization (ROP) capability of a wide range sulfonamide-supported aluminum alkyl alkoxide complexes are reported. synthesis the new protio-ligands PhCH2N(CH2CH2NHSO2R)2 (R = Tol (15, H2N2TsNPh) or Me (16, H2N2MsNPh)) is described. These previously reported 1,2-C6H10(NHSO2R)2 (11, H2CyN2Ts) Mes (12, H2CyN2SO2Mes)) RCH2N(CH2CH2NHSO2Tol)2 MeOCH2 (13, H2N2TsNOMe) 2-NC5H4 (14, H2N2TsNpy)) reacted with AlEt3 to form Al(CyN2Ts)Et(THF) (17),...
Reaction of In(CH2SiMe3)3 with H2N2TsNpy or H2N2TsNOMe gave the five-coordinate indium alkyls In(N2TsNpy)(CH2SiMe3) (14) and In(N2TsNOMe)(CH2SiMe3) (15). The corresponding reaction H2N2TsNPh four-coordinate In(N2TsNPh)(CH2SiMe3) (16). In{N(SiMe3)2}3 amide In(N2TsNpy){N(SiMe3)2} (19). Na2N2TsNpy InCl3 in THF followed by LiOiPr "ate" product In(N2TsNpy)(OiPr)Cl{Li(THF)} (21). chloride complex In(N2TsNpy)Cl(py) (22) was also isolated. H2O2MeNpy bis(phenolate)amine compound In(O2MeNpy)(CH2SiMe3)...
Reaction of the OOO-coordinating tridentate bis(phenolate) protio-ligand 2,2′-{oxybis(methylene)}bis{4,6-di(1-methyl-1-phenylethyl)phenol} (LO3-H2), with 1 equiv. KN(SiMe3)2 in toluene or THF yielded [K(LO3-H)] (1) [K(LO3-H)(THF)] (2), respectively. Single-crystal X-ray diffraction studies and 2 revealed mononuclear structures phenyl rings bulky ligand displaying stabilising π-interactions to potassium centre. LO3-H2 also reacts ZnEt2 MgnBu2 give [M2(LO3)2] (M = Zn (3) Mg (4)) good yield....
Treatment of TiCl 4 with Bu t NH 2 (6 equivalents) followed by addition bpy (2 equivalents, 4-tert-butylpyridine) or pyridine (py) afforded the five- six-co-ordinate tert-butylimido complexes [Ti(NBu )Cl (bpy) ] n (n = 3*) respectively in good yields. Reaction 3 RNH gave corresponding arylimido derivatives [Ti(NR)Cl (R Ph,* C 6 H Me-4,* NO -4,* Me -2,6 Pr i -2,6). Addition tmen pmdien to respectively) bi- tri-dentate amine complexes, (tmen)] (pmdien)]* (tmen NCH CH NMe , N,N,N′,N ″,N″...
New single-, double-, and cross-coupling imido group transfer reactions of cyclopentadienyl-amidinate titanium complexes are described. Reaction Ti(η-C5R4Me)(NtBu)Cl(py) (R = Me or H) with the lithiated benzamidinate Li[PhC(NSiMe3)2] acetamidinate Li[MeC(NiPr)2] afforded tert-butyl Ti(η-C5R4Me)(NtBu){PhC(NSiMe3)2} (5) H (7)) Ti(η-C5R4Me)(NtBu){MeC(NiPr2)2} (6) (8)), respectively. 6 ArNH2 TolNH2 (Ar 2,6-C6H3Me2, Tol 4-C6H4Me) corresponding aryl Ti(η-C5Me5)(NR){MeC(NiPr2)2} Ar (9) (10))....
New groups 3 and 4 organometallic coordination compounds supported by the tetradentate diamino-bis(phenolate) ligands O2tBuNN' O2MeNN' are reported [H2O2RNN' = (2-C5H4N)CH2N(2-HO-3,5-C6H2R2)2 where R tBu or Me] along with some comparative studies tridentate amino-bis(phenolate) ligand O2tBuN (H2O2tBuN nPrN(2-HO-3,5-C6H2tBu2)2). Reaction of Na2O2tBuNN' ScCl3 pyridine in THF gave monomeric Sc(O2tBuNN')Cl(py) (2), whereas Na2O2MeNN' dimeric phenoxy-bridged Sc2(O2MeNN')2Cl2 (3). YCl3 neat...
Reaction of RCH2N(CH2CH2NHSO2Tol)2 (R = 2-NC5H4 (8, H2Lpy) or MeOCH2 (9, H2LOMe)) with Ti(NMe2)4 at room temperature afforded Ti(Lpy)(NMe2)2 (10) Ti(LOMe)(NMe2)2 (11), respectively, which contain tetradentate bis(sulfonamide)amine ligands. The corresponding reactions Ti(OiPr)4 Zr(OiPr)4·HOiPr required more forcing conditions to form the homologous bis(isopropoxide) analogues, M(LR)(OiPr)2 (M Ti, R py (12) OMe (14); M Zr, (13) (15)). Ti(NMe2)2(OiPr)2 H2LR formed 12 14 under milder conditions....