A5035821059- Organometallic Complex Synthesis and Catalysis
- Synthetic Organic Chemistry Methods
- Synthesis and characterization of novel inorganic/organometallic compounds
- Organoboron and organosilicon chemistry
- Organoselenium and organotellurium chemistry
- Asymmetric Synthesis and Catalysis
- Sulfur-Based Synthesis Techniques
- Organic and Inorganic Chemical Reactions
- Coordination Chemistry and Organometallics
- Carbon dioxide utilization in catalysis
- Mass Spectrometry Techniques and Applications
- Chemical Synthesis and Reactions
- Asymmetric Hydrogenation and Catalysis
- Radioactive element chemistry and processing
- Wildlife-Road Interactions and Conservation
- Advanced Polymer Synthesis and Characterization
- Catalytic Processes in Materials Science
- Silicone and Siloxane Chemistry
- biodegradable polymer synthesis and properties
- Crystallography and molecular interactions
- Land Use and Ecosystem Services
- Chemical Synthesis and Analysis
- Surface Chemistry and Catalysis
- Boron Compounds in Chemistry
- Surfactants and Colloidal Systems
University of Eastern Finland
2018-2025
McGill University
2025
University of Victoria
2013-2024
Finland University
2024
Ecological Society of America
2016-2020
John Wiley & Sons (United States)
2018-2020
Wyoming Game and Fish Department
2019
IFC Research (United Kingdom)
2018-2019
University of Akron
2002-2012
University of Leeds
2012
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectronic effects of Ziegler-Natta polymerization propylene and ethylene using soluble metallocene catalystsIk Mo Lee, William J. Gauthier, JoAnne M. Ball, Bhagavathi Iyengar, Scott CollinsCite this: Organometallics 1992, 11, 6, 2115–2122Publication Date (Print):June 1, 1992Publication History Published online1 May 2002Published inissue 1 June 1992https://pubs.acs.org/doi/10.1021/om00042a027https://doi.org/10.1021/om00042a027research-articleACS...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGroup-transfer polymerization using cationic zirconocene compoundsScott Collins and David G. WardCite this: J. Am. Chem. Soc. 1992, 114, 13, 5460–5462Publication Date (Print):June 1, 1992Publication History Published online1 May 2002Published inissue 1 June 1992https://pubs.acs.org/doi/10.1021/ja00039a088https://doi.org/10.1021/ja00039a088research-articleACS PublicationsRequest reuse permissionsArticle Views571Altmetric-Citations172LEARN ABOUT...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolymerization of propylene using supported, chiral, ansa-metallocene catalysts: production polypropylene with narrow molecular weight distributionsScott Collins, W. Mark Kelly, and David A. HoldenCite this: Macromolecules 1992, 25, 6, 1780–1785Publication Date (Print):March 1, 1992Publication History Published online1 May 2002Published inissue 1 March...
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTNew Bifunctional Perfluoroaryl Boranes. Synthesis and Reactivity of the ortho-Phenylene-Bridged Diboranes 1,2-[B(C6F5)2]2C6X4 (X = H, F)'V. Clifford Williams, Warren E. Piers, William Clegg, Mark R. J. Elsegood, Scott Collins, Todd B. MarderView Author Information Department Chemistry, University Calgary 2500 Drive N. W. Calgary, Alberta, Canada T2N 1N4 Newcastle upon Tyne NE1 7RU, England Waterloo Waterloo, Ontario, N2L 3G1 South Road...
Synthesis of "meso"- and "racemic"-like diastereomers Me2Si(3-MeInd)(Ind)ZrCl2 (5 6, respectively) was achieved through either metathetical reactions between the dianion Me2(3-MeIndH)(IndH) (4) with ZrCl4 or via amine elimination reactions, followed by fractional crystallization. Propylene polymerizations using meso-5 in presence methyl aluminoxane under a variety conditions leads to formation low molecular weight, semicrystalline, tacticity, poly(propylene) (PP). The dominant chain transfer...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElastomeric Poly(propylene): Influence of Catalyst Structure and Polymerization Conditions on Polymer PropertiesWilliam J. Gauthier, John F. Corrigan, Nicholas Taylor, Scott CollinsCite this: Macromolecules 1995, 28, 11, 3771–3778Publication Date (Print):May 1, 1995Publication History Published online1 May 2002Published inissue 1 1995https://pubs.acs.org/doi/10.1021/ma00115a004https://doi.org/10.1021/ma00115a004research-articleACS...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelenosulfonation of acetylenes: preparation novel .beta.-(phenylseleno)vinyl sulfones and their conversion to acetylenic .beta.-functionalized sulfonesThomas G. Back, Scott Collins, Russell KerrCite this: J. Org. Chem. 1983, 48, 18, 3077–3084Publication Date (Print):September 1, 1983Publication History Published online1 May 2002Published inissue 1 September...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe tetrasilabicyclo[1.1.0]butane system: preparation and characterization of 1,3-di-tert-butyl-2,2,4,4-tetrakis(2,6-diethylphenyl)tetrasilabicyclo[1.1.0]butaneSatoru Masamune, Yoshio Kabe, Scott Collins, David J. Williams, Ray JonesCite this: Am. Chem. Soc. 1985, 107, 19, 5552–5553Publication Date (Print):September 1, 1985Publication History Published online1 May 2002Published inissue 1 September...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelenosulfonation: boron trifluoride catalyzed or thermal addition of selenosulfonates to olefins. A novel regio- and stereocontrolled synthesis vinyl sulfonesThomas G. Back Scott CollinsCite this: J. Org. Chem. 1981, 46, 16, 3249–3256Publication Date (Print):July 1, 1981Publication History Published online1 May 2002Published inissue 1 July 1981https://pubs.acs.org/doi/10.1021/jo00329a021https://doi.org/10.1021/jo00329a021research-articleACS...
Abstract Electrospray‐ionization mass spectrometric studies of poly(methylaluminoxane) (MAO) in the presence [Cp 2 ZrMe ], ZrMe(Cl)], and ZrCl ] fluorobenzene (PhF) solution are reported. The results demonstrate that alkylation ionization separate events occur at competitive rates a polar solvent. Furthermore, there significant differences ion‐pair speciation result from use metallocene dichloride complexes comparison to alkylated precursors otherwise identical Al/Zr ratios. Finally, counter...
The polymerization of methyl methacrylate (MMA), initiated by zirconocene complexes Cp2ZrMe2 (1) and [Cp2ZrMe(THF)][BPh4] (2), provides partially syndiotactic poly(methyl methacrylate) (PMMA) in high yield with a narrow molecular weight distribution (MWD). kinetics this process were studied reveal that system, the rate initiation is much slower than propagation. Initiation appears to involve rate-limiting reaction complex 2 monomer generate cationic enolate (3). latter compounds also...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGroup-Transfer Polymerization Using Metallocene Catalysts: Propagation Mechanisms and Control of Polymer StereochemistryScott Collins, David G. Ward, Kevin H. SuddabyCite this: Macromolecules 1994, 27, 24, 7222–7224Publication Date (Print):November 1, 1994Publication History Published online1 May 2002Published inissue 1 November 1994https://pubs.acs.org/doi/10.1021/ma00102a037https://doi.org/10.1021/ma00102a037research-articleACS...
Mono- and disubstituted bis(ketenimine) complexes of zirconium (1 2, respectively) can be readily prepared by reaction these ligands (3) with Zr(NMe)4 or, in some cases, the homoleptic tetrabenzyl derivative ZrBn4. Treatment 1 (Ar = Ph, p-CF3Ph; X NMe2) Me2NH·HCl 2 either or TMSCl provides corresponding chloro derivatives high yield. Alkyl (X Me, Bn) Grignard organolithium reagents. Monocyclopentadienyl 4 Cp η5-C5H5, η5-C9H7; Cl) were from CpLi IndLi yield, methyl Me) accessible treatment...
The weakly coordinating anions {C6F4-1,2-[B(C6F5)2]2(μ-OR)}- (R = CH3, C6F5) were prepared as their trityl salts (2-OR) and fully characterized. Stoichiometric reactions with Cp2ZrMe2 yield dimeric (3-OR) or monomeric (4-OR) metallocenium ions; the latter are highly effective cocatalysts for ethylene polymerization.
Ethylene polymerizations were conducted using β-diketimine complexes of Zr [LZrX3 (1) and L2ZrX2 (2) with L = MeC(NAr)CHC(NAr)Me X Cl, R (R Me, Bn)] as well Cp(L)ZrX2 (3) in the presence MAO. Complexes 1 possess low polymerization activities (ca. 105 g PE/(mol h)) provide PEs a trimodal, molecular weight distribution. Both 2 3 behave single-site catalysts under these conditions, activity latter being considerably higher than former 106−107 vs h)). Induction periods 10−20 min at 70 °C...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe microstructure of poly(cyclopentene) produced by polymerization cyclopentene with homogeneous Ziegler-Natta catalystsScott Collins and W. Mark KellyCite this: Macromolecules 1992, 25, 1, 233–237Publication Date (Print):January 1992Publication History Published online1 May 2002Published inissue 1 January 1992https://pubs.acs.org/doi/10.1021/ma00027a039https://doi.org/10.1021/ma00027a039research-articleACS PublicationsRequest reuse...
Electrospray ionization mass spectrometric studies of poly(methylaluminoxane) (MAO) in the presence Cp2ZrMe2, octamethyltrisiloxane (OMTS), or [Bu4N]Cl fluorobenzene solution are reported. The results concur with hypothesis that MAO is partially ionized sufficiently polar media, where contact ion pairs general formula [Me2Al][(MeAlO)x(AlMe3)yMe]. A limited number compositions this type detected; most abundant has x = 23 and y 7, cation [Me2Al(OMTS)]+ (with m/z 293) anion 1853) were detected...
In the presence of weak donor octamethyltrisiloxane (OMTS), methylalumoxane (MAO) undergoes ionization through [Me2Al]+ abstraction. The [Me2Al·OMTS]+[(MeAlO)x(Me3Al)yMe]− ion pairs formed can conveniently be studied by electrospray mass spectrometry. anion distribution changes with OMTS:Al ratio, low molecular weight (MW) anions forming at high ratios due to oligomer degradation. Monitoring room-temperature aging shows that MAO oligomers MW are slowly and systematically converted species...
The structure and reactivity of small methylaluminoxane (MAO) species (MeAlO)n(Me3Al)m (n = 1‐8) have been investigated using DFT (M06‐2X), MP2, CCSD(T) calculations. This hierarchy methods reveals that artificially stabilizes structures containing 4‐coordinate oxygen atoms while higher‐level calculations demonstrate a clear preference for with 3‐coordinate aluminum centers. Analysis ionization pathways shows these neutral MAO molecules form anions through either methide or Me2Al+...
The properties of materials containing azobenzene depend strongly on the dynamics cis and trans isomerization which in turn are influenced by presence different possible tautomers. Two commonly used food azo dyes, Allura Red (ALR) Amaranth (AMA), were studied NMR spectroscopy to experimentally determine their tautomeric forms then theoretically rationalized. Variable temperature 2D 1H-15N HMBC provided a direct measure hydrazone percentage dyes solution was complimented 1H ultrafast...
Efficient syntheses of iminophosphonamide [R2P(NR')NHR'] complexes group 4 via amine elimination reactions and the solid-state structures [R2P(NR')2]2ZrCl2 mixed Cp[R2P(NR')2]ZrCl2 are reported. These active, ethylene, polymerization catalysts (106−107 g PE/mol Zr × h) in presence MAO provide high molecular weight poly(ethylene) with narrow distributions.
Lewis acidic diborane 1 (J. Am. Chem. Soc. 1999, 121, 3244−3245) is highly effective for both proton- and cationogen-initiated isobutene polymerization in hydrocarbon media at low temperature. Reactions of with cumyl chloride methyl ether were studied by variable-temperature 1H 19F NMR spectroscopy. At temperatures stable ion pairs 2a 2b are formed; higher these ion-pairs form phenyl-1,3,3-trimethylindan (3) concomitant release HCl to the case or degradation anion (2b). Reaction between...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElastomeric Poly(propylene): Propagation Models and Relationship to Catalyst StructureWilliam J. Gauthier Scott CollinsCite this: Macromolecules 1995, 28, 11, 3779–3786Publication Date (Print):May 1, 1995Publication History Published online1 May 2002Published inissue 1 1995https://pubs.acs.org/doi/10.1021/ma00115a005https://doi.org/10.1021/ma00115a005research-articleACS PublicationsRequest reuse permissionsArticle Views678Altmetric-Citations85LEARN...