Imperial College London

PROFESSOR CHARLOTTE K. WILLIAMS

Faculty of Natural SciencesDepartment of Chemistry

Visiting Professor
 
 
 
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Contact

 

+44 (0)20 7594 5790c.k.williams Website

 
 
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Location

 

317 RCS1ChemistrySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

170 results found

Kember MR, Copley J, Buchard A, Williams CKet al., 2012, Triblock copolymers from lactide and telechelic poly(cyclohexene carbonate), POLYMER CHEMISTRY, Vol: 3, Pages: 1196-1201, ISSN: 1759-9954

Journal article

Kember MR, Jutz F, Buchard A, White AJP, Williams CKet al., 2012, Di-cobalt(II) catalysts for the copolymerisation of CO2 and cyclohexene oxide: support for a dinuclear mechanism?, CHEMICAL SCIENCE, Vol: 3, Pages: 1245-1255, ISSN: 2041-6520

The synthesis and characterisation of a series of di-cobalt(II) halide complexes, coordinated by a macrocyclic ancillary ligand, is reported. The new complexes show excellent activity as catalysts for the copolymerisation of cyclohexene oxide (CHO) and carbon dioxide, under just 1 atmosphere of pressure of CO2. The complexation of a series of co-ligands has been investigated, including nucleophiles of varying strength, (4-dimethylaminopyridine (DMAP), N-methylimidazole (MeIm) and pyridine), and the anionic donor (Cl) from bulky ammonium salts, ([HNEt3]Cl, [DBU-H]Cl and [MTBD-H]Cl). Structure-activity studies of the complexes, including X-ray crystallography data, in conjunction with mass spectrometry experiments, are used to support a proposed dinuclear mechanism. The initial rate of copolymerisation, determined using in situ attenuated total reflectance infrared (ATR-IR) spectroscopy, shows a first order dependence on both the catalyst concentration and the concentration of cyclohexene oxide. A dinuclear mechanism is proposed in which catalysis occurs on the convex face of the molecule, leading to chain growth from a single site.

Journal article

Buchard A, Bakewell CM, Weiner J, Williams CKet al., 2012, Recent Developments in Catalytic Activation of Renewable Resources for Polymer Synthesis, ORGANOMETALLICS AND RENEWABLES, Editors: Meier, Weckhuysen, Bruijnincx, Publisher: SPRINGER-VERLAG BERLIN, Pages: 175-224, ISBN: 978-3-642-28287-4

Book chapter

Jutz F, Buchard A, Kember MR, Fredriksen SB, Williams CKet al., 2011, Mechanistic Investigation and Reaction Kinetics of the Low-Pressure Copolymerization of Cyclohexene Oxide and Carbon Dioxide Catalyzed by a Dizinc Complex, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 133, Pages: 17395-17405, ISSN: 0002-7863

Journal article

Kember MR, Jutz F, White AJ, Buchard A, Williams CKet al., 2011, Dinuclear catalysts for the copolymerization of cyclohexene oxide and CO2, 242nd National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727

Conference paper

Holmes AB, Jones DJ, Wong WWH, Kwon T-H, Seyler H, Watkins SE, Borthwick RJ, McCluskey GE, Raja IUH, Williams CK, Keyworth CW, Chan KLet al., 2011, Synthesis of conjugated materials for light emission and light harvesting, 242nd National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727

Conference paper

Platel RH, White AJP, Williams CK, 2011, Bis(phosphinic)diamido Yttrium Amide, Alkoxide, and Aryloxide Complexes: An Evaluation of Lactide Ring-Opening Polymerization Initiator Efficiency, INORGANIC CHEMISTRY, Vol: 50, Pages: 7718-7728, ISSN: 0020-1669

Journal article

Haider A, Williams CK, 2011, Polylactides with aldaric ester end groups or chain extending groups, COMPTES RENDUS CHIMIE, Vol: 14, Pages: 736-744, ISSN: 1631-0748

Journal article

Orchard KL, Harris JE, White AJP, Shaffer MSP, Williams CKet al., 2011, Solvent Dependence of the Structure of Ethylzinc Acetate and Its Application in CO2/Epoxide Copolymerization, ORGANOMETALLICS, Vol: 30, Pages: 2223-2229, ISSN: 0276-7333

Journal article

Cary SK, Thompson SM, Haaf MP, Williams CK, Platel RHet al., 2011, Stereoselective lactide polymerization with aluminum catalysts, 241st National Meeting and Exposition of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727

Conference paper

Buchard A, Kember MR, Sandeman KG, Williams CKet al., 2011, A bimetallic iron(III) catalyst for CO2/epoxide coupling, CHEMICAL COMMUNICATIONS, Vol: 47, Pages: 212-214, ISSN: 1359-7345

Journal article

Kember MR, Buchard A, Williams CK, 2011, Catalysts for CO2/epoxide copolymerisation, CHEMICAL COMMUNICATIONS, Vol: 47, Pages: 141-163, ISSN: 1359-7345

Journal article

Donaghey JE, Ashraf RS, Kim Y, Huang ZG, Nielsen CB, Zhang W, Schroeder B, Grenier CRG, Brown CT, D'Angelo P, Smith J, Watkins S, Song K, Anthopoulos TD, Durrant JR, Williams CK, McCulloch Iet al., 2011, Pyrroloindacenodithiophene containing polymers for organic field effect transistors and organic photovoltaics, Journal of Materials Chemistry, Vol: 21, Pages: 18744-18752, ISSN: 0959-9428

The synthesis of the novel electron-rich pyrroloindacenodithiophene (NIDT) unit is reported. Stille copolymerization of the distannylated NIDT unit, with the electron-deficient dibrominated benzothiadiazole (BT), difluorobenzothiadiazole (ffBT), thienopyrrolodione (TPD) and 1,1[prime or minute]-bithienopyrrolodione (biTPD) units afforded a series of low band gap semiconducting polymers. Initial testing shows promise for the use of these materials as p-type semiconductors in organic field effect transistors (OFETs) with mobilities as high as 0.07 cm2V-1s-1 being measured. These materials have also been tested as the donor polymer in polymer/fullerene bulk heterojunction organic photovoltaics (OPVs) giving maximum efficiencies of 2.5%.

Journal article

Keyworth CW, Chan KL, Labram JG, Anthopoulos TD, Watkins SE, McKiernan M, White AJP, Holmes AB, Williams CKet al., 2011, The tuning of the energy levels of dibenzosilole copolymers and applications in organic electronics, Journal of Materials Chemistry, Vol: 21, Pages: 11800-11814, ISSN: 0959-9428

An understanding of the structure-function relationships of conjugated polymers is an invaluable resource for the successful design of new materials for use in organic electronics. To this end, we report the synthesis, characterisation and optoelectronic properties of a range of new alternating copolymers of dibenzosilole. Suzuki polycondensation reactions were used to afford a series of eight conjugated materials by the respective combination of either a 3,6- or 2,7-linked 9,9-dioctyldibenzosilole with 3,6-linked-N-octylcarbazole, triarylamine, oxadiazole and triazole monomers. The copolymers were fully characterised using 1H, 13C{1H} NMR spectroscopy, size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The photophysical properties were determined using UV-Vis spectroscopy, photoluminescence (PL) measurements, cyclic voltammetry (CV) and photoelectron emission spectroscopy in air (PESA). The spectroscopic and electrochemical measurements were used to determine the materials' HOMO and LUMO energies and the values were correlated with the copolymer composition and structure. A selection of the copolymers (P4, P5 and P8) were evaluated as the active layer within single-layer polymer light emitting diodes (PLEDs), with the configuration: glass/ITO/PEDOT:PSS/emissive layer/Ba/Al, which gave low intensity electroluminescence. The selected copolymers were also evaluated as the organic semiconductor in bottom-gate, bottom-contact organic field effect transistors (OFETs). The best performing devices gave a maximum mobility of 3 [times] 10-4 cm2 V-1 s-1 and on/off current ratios of 105.

Journal article

Albert-Seifried S, Hodgkiss JM, Laquai F, Bronstein HA, Williams CK, Friend RHet al., 2010, Pressure-Induced Delocalization of Photoexcited States in a Semiconducting Polymer, PHYSICAL REVIEW LETTERS, Vol: 105, ISSN: 0031-9007

Journal article

Tang M, Dong Y, Stevens MM, Williams CKet al., 2010, Tailoring Polylactide Degradation: Copolymerization of a Carbohydrate Lactone and S,S-Lactide, Macromolecules, Vol: 43, Pages: 7556-7564, ISSN: 0024-9297

Journal article

Kember MR, Williams CK, 2010, Cobalt catalysts for the copolymerization of epoxides and carbon dioxide, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol: 240, ISSN: 0065-7727

Journal article

Williams CK, Kember MR, White AJP, 2010, Bimetallic catalysts for CO2-cyclohexene oxide copolymerizations, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol: 240, ISSN: 0065-7727

Journal article

Mac Dowell N, Florin N, Buchard A, Hallet J, Galindo A, Jackson G, Adjiman C, Williams CK, Shah N, Fennell PSet al., 2010, An Overview of CO2 capture technologies, Energy and Environmental Science, Vol: 3, Pages: 1645-1669

Journal article

Buchard A, Platel RH, Auffrant A, Le Goff XF, Le Floch P, Williams CKet al., 2010, Iminophosphorane Neodymium(III) Complexes As Efficient Initiators for Lactide Polymerization, ORGANOMETALLICS, Vol: 29, Pages: 2892-2900, ISSN: 0276-7333

Journal article

Levine A, Roaf J, Haaf MP, Williams CK, Platel Ret al., 2010, Lactide polymerization with chiral aluminum catalysts, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol: 239, ISSN: 0065-7727

Journal article

Kember MR, White AJP, Williams CK, 2010, Highly Active Di- and Trimetallic Cobalt Catalysts for the Copolymerization of CHO and CO2 at Atmospheric Pressure, MACROMOLECULES, Vol: 43, Pages: 2291-2298, ISSN: 0024-9297

Journal article

Howard IA, Hodgkiss JM, Zhang X, Kirov KR, Bronstein HA, Williams CK, Friend RH, Westenhoff S, Greenham NCet al., 2010, Charge Recombination and Exciton Annihilation Reactions in Conjugated Polymer Blends, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 132, Pages: 328-335, ISSN: 0002-7863

Journal article

Orchard KL, White AJP, Shaffer MSP, Williams CKet al., 2009, Pentanuclear Complexes for a Series of Alkylzinc Carboxylates, ORGANOMETALLICS, Vol: 28, Pages: 5828-5832, ISSN: 0276-7333

Journal article

Kember MR, White AJP, Williams CK, 2009, Di- and Tri-Zinc Catalysts for the Low-Pressure Copolymerization of CO2 and Cyclohexene Oxide, INORGANIC CHEMISTRY, Vol: 48, Pages: 9535-9542, ISSN: 0020-1669

Journal article

Tang M, Steves MM, Williams CK, 2009, Polymerization of a carbohydrate lactone, WO2009118538 (A2)

Patent

Horst S, Evans NR, Bronstein HA, Williams CKet al., 2009, Synthesis of Fluoro-Substituted Silole-Containing Conjugated Materials, JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, Vol: 47, Pages: 5116-5125, ISSN: 0887-624X

Journal article

Kember MR, Knight PD, Williams CK, 2009, New bimetallic zinc catalyst for the copolymerization of carbon dioxide and cyclohexene oxide at 1 atm, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol: 237, ISSN: 0065-7727

Journal article

Orchard KL, Gonzalez-Campo A, Shaffer MSP, Williams CKet al., 2009, Mild synthesis of zinc oxide nanoparticles via an organometallic method, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol: 237, ISSN: 0065-7727

Journal article

Wells TP, Hallett JP, Williams CK, Welton Tet al., 2009, ORGN 201-Esterification in ionic liquids: The influence of solvent basicity, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol: 237, ISSN: 0065-7727

Journal article

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