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1,373 results on '"Cordes, David"'

202. Fast Delayed Emission in New Pyridazine-Based Compounds

Author

Krotkus, Simonas, primary, Matulaitis, Tomas, additional, Diesing, Stefan, additional, Copley, Graeme, additional, Archer, Emily, additional, Keum, Changmin, additional, Cordes, David B., additional, Slawin, Alexandra M. Z., additional, Gather, Malte C., additional, Zysman-Colman, Eli, additional, and Samuel, Ifor D. W., additional

Published
2021
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205. Assessing the economic return of specializing in orthodontics or oral and maxillofacial surgery

Author

Cordes, David W., Doherty, Neville, and Lopez, Rene

Subjects
Oral surgery -- Economic aspects, Orthodontics -- Economic aspects, Health
Abstract

Dentists will most likely get a positive return on their educational investment if they specialize in orthodontics or oral and facial surgery. Surgeons should receive a greater return on their investment because they will break even sooner and make more money than orthodontists. This should encourage dental students to pursue specialty training.

Published
2001

208. Efficient Sky‐Blue Organic Light‐Emitting Diodes Using a Highly Horizontally Oriented Thermally Activated Delayed Fluorescence Emitter

Author

Zhang, Zhen, primary, Crovini, Ettore, additional, dos Santos, Paloma L., additional, Naqvi, Bilal A., additional, Cordes, David B., additional, Slawin, Alexandra M. Z., additional, Sahay, Prakhar, additional, Brütting, Wolfgang, additional, Samuel, Ifor D. W., additional, Bräse, Stefan, additional, and Zysman‐Colman, Eli, additional

Published
2020
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213. Thionylimido Complexes

Author

McGeachie, Liam J. R., primary, Carpenter‐Warren, Cameron L., additional, Cordes, David B., additional, Bühl, Michael, additional, Gray, Steven J., additional, Hua, Guoxiong, additional, Slawin, Alexandra M. Z., additional, and Woollins, J. Derek, additional

Published
2020
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222. Homochiral Emissive Λ8‐ and Δ8‐[Ir8Pd4]16+ Supramolecular Cages

Author

Rota Martir, Diego, Escudero, Daniel, Jacquemin, Denis, Cordes, David B., Slawin, Alexandra M. Z., Fruchtl, Herbert A., Warriner, Stuart L., and Zysman‐Colman, Eli

Subjects
photochemistry, Full Paper, Supramolecular Cages, self-assembly, Full Papers, iridium, cage compounds, palladium
Abstract

Synthetic self‐assembly is a powerful technique for the bottom‐up construction of discrete and well‐defined polyhedral nanostructures resembling the spherical shape of large biological systems. In recent years, numerous Archimedean‐shaped coordination cages have been reported based on the assembly of bent monodentate organic ligands containing two or more distal pyridyl rings and square‐planar PdII ions. The formation of photoactive PdII metallamacrocycles and cages, however, remain rare. Here we report the first examples of emissive and homochiral supramolecular cages of the form [Ir8Pd4]16+. These cages provide a suitably sized cavity to host large guest molecules. Importantly, encapsulation and energy transfer have been observed between the blue‐emitting NBu4[Ir(dFppy)2(CN)2] guest and the red‐emitting Δ8‐[Ir8Pd4]16+ cage.

Published
2017

224. A Low-Spin Co II /Nitroxide Complex for Distance Measurements at Q-Band Frequencies.

Author

Giannoulis, Angeliki, Cordes, David B., Slawin, Alexandra M. Z., and Bode, Bela E.

Subjects
ELECTRON paramagnetic resonance spectroscopy, ELECTRON spin, CARBON dioxide, X-ray crystallography, DISTANCES
Abstract

Pulse dipolar electron paramagnetic resonance spectroscopy (PDS) is continuously furthering the understanding of chemical and biological assemblies through distance measurements in the nanometer range. New paramagnets and pulse sequences can provide structural insights not accessible through other techniques. In the pursuit of alternative spin centers for PDS, we synthesized a low-spin CoII complex bearing a nitroxide (NO) moiety, where both the CoII and NO have an electron spin S of 1/2. We measured CoII-NO distances with the well-established double electron–electron resonance (DEER aka PELDOR) experiment, as well as with the five- and six-pulse relaxation-induced dipolar modulation enhancement (RIDME) spectroscopies at Q-band frequencies (34 GHz). We first identified challenges related to the stability of the complex in solution via DEER and X-ray crystallography and showed that even in cases where complex disproportionation is unavoidable, CoII-NO PDS measurements are feasible and give good signal-to-noise (SNR) ratios. Specifically, DEER and five-pulse RIDME exhibited an SNR of ~100, and while the six-pulse RIDME exhibited compromised SNR, it helped us minimize unwanted signals from the RIDME traces. Last, we demonstrated RIDME at a 10 μM sample concentration. Our results demonstrate paramagnetic CoII to be a feasible spin center in medium magnetic fields with opportunities for PDS studies involving CoII ions. [ABSTRACT FROM AUTHOR]

Published
2022
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225. Conjugated, rigidified bibenzimidazole ancillary ligands for enhanced photoluminescence quantum yields of orange/red-emitting iridium(iii) complexes

Author

Henwood, Adam F., Antón-García, Daniel, Morin, Mégane, Rota Martir, Diego, Cordes, David B., Casey, Colin, Slawin, Alexandra M. Z., Lebl, Tomas, Bühl, Michael, Zysman-Colman, Eli, EPSRC, University of St Andrews. Organic Semiconductor Centre, University of St Andrews. School of Chemistry, and University of St Andrews. EaSTCHEM

Subjects
Steric effects, Photoluminescence, 010405 organic chemistry, Chemistry, Ligand, chemistry.chemical_element, Quantum yield, DAS, Conjugated system, QD Chemistry, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, Crystallography, chemistry.chemical_compound, Diamine, Pyridine, QD, Iridium
Abstract

A family of six orange/red-emitting cationic iridium complexes were synthesized and their optoelectronic properties comprehensively characterized., A series of six novel [Ir(C^N) (N^N)](PF ) complexes (C^N is one of two cyclometalating ligands: 2-phenyl-4-(2,4,6-trimethylphenyl)pyridine, MesppyH, or 2-(napthalen-1-yl)-4-(2,4,6-trimethylphenyl)pyridine, MesnpyH; N^N denotes one of four neutral diamine ligands: 4,4′-di- -butyl-2,2′-bipyridine, dtbubpy, 1 ,1′ -2,2′-bibenzimiazole, H bibenz, 1,1′-(α,α′- -xylylene)-2,2′-bibenzimidazole, -xylbibenz or 2,2′-biquinoline, biq) were synthesised and their structural, electrochemical and photophysical properties comprehensively characterised. The more conjugated MesnpyH ligands confer a red-shift in the emission compared to MesppyH but maintain high photoluminescence quantum yields due to the steric bulk of the mesityl groups. The H bibenz and -xylbibenz ligands are shown to be electronically indistinct to dtbubpy but give complexes with higher quantum yields than analogous complexes bearing dtbubpy. In particular, the rigidity of the -xylbibenz ligand, combined with the steric bulk of the MesnpyH C^N ligands, gives a red-emitting complex ( = 586, 623 nm) with a very high photoluminescence quantum yield ( = 44%) for an emitter in that region of the visible spectrum. These results suggest that employing these ligands is a viable strategy for designing more efficient orange-red emitters for use in a variety of photophysical applications.

Published
2019

227. Scope, Limitations and Mechanistic Analysis of the HyperBTM‐Catalyzed Acylative Kinetic Resolution of Tertiary Heterocyclic Alcohols**.

Author

Smith, Samuel M., Greenhalgh, Mark D., Feoktistova, Taisiia, Walden, Daniel M., Taylor, James E., Cordes, David B., Slawin, Alexandra M. Z., Cheong, Paul Ha‐Yeon, and Smith, Andrew D.

Subjects
KINETIC resolution, ALCOHOL, METHANOL, ACYLATION
Abstract

The full scope and limitations of the catalytic acylative kinetic resolution of a range of tertiary heterocyclic alcohols (78 examples, s up to >200) is reported under operationally‐simple conditions, using low loadings of a commercially available Lewis basic isothiourea catalyst, HyperBTM (generally 1 mol %). The protocol is highly effective for the kinetic resolution of 3‐substituted 3‐hydroxyoxindole and α‐substituted α‐hydroxylactam derivatives bearing up to three potential recognition motifs at the stereogenic tertiary carbinol center. The full power of this methodology has been showcased through the synthesis of highly enantioenriched biologically‐active target compounds in both enantiomeric forms. To provide further insight into the reaction mechanism, a detailed kinetic analysis of this Lewis base‐catalyzed acylation of tertiary alcohols is reported using the variable time normalization analysis (VTNA) method. [ABSTRACT FROM AUTHOR]

Published
2022
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229. 6-exo-trig Michael addition-lactonizations for catalytic enantioselective chromenone synthesis† †Electronic supplementary information (ESI) available: Experimental procedures; characterization data for novel compounds; 1H and 13C NMR spectra, HPLC traces,12 and X-ray crystallographic data files compounds 9 and 27 (CIF). CCDC 1510311 and 1510312. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6cc10178j Click here for additional data file. Click here for additional data file

Author

Neyyappadath, Rifahath M., Cordes, David B., Slawin, Alexandra M. Z., and Smith, Andrew D.

Subjects
Chemistry
Abstract

The catalytic enantioselective 6-exo-trig Michael addition-lactonization of enone-acid substrates to form cis-chromenones with high diastereo- and enantiocontrol was developed using the commercially available isothiourea tetramisole., The catalytic enantioselective 6-exo-trig Michael addition-lactonization of enone-acid substrates to form cis-chromenones with high diastereo- and enantiocontrol was developed using the commercially available isothiourea tetramisole. An acidic workup proved necessary to minimize product epimerization and maximize product er, providing cis-chromenones in excellent yield, and with excellent diastereo- and enantioselectivity.

Published
2017

230. Automated flow graph-based testing of object-oriented software modules

Author

Parrish, Allen S., Borie, Richard B., and Cordes, David S.

Subjects
Systems Software, Testing, Modules, Applications Programming, New Technique, Automated flow chart, Object-oriented programming, Automated flow chart -- Usage, Object-oriented programming -- Methods
Published
1993

231. Enantioselective Stereodivergent Nucleophile‐Dependent Isothiourea‐Catalysed Domino Reactions

Author

Matviitsuk, Anastassia, Taylor, James E., Cordes, David B., Slawin, Alexandra M. Z., and Smith, Andrew D.

Subjects
Full Paper, Lewis base, Organic Chemistry, domino reactions, organocatalysis, enantioselective synthesis, Full Papers, α,β-unsaturated acyl ammonium
Abstract

α,β‐Unsaturated acyl ammoniums generated from the reaction of α,β‐unsaturated 2,4,6‐trichlorophenol (TCP) esters bearing a pendent enone with an isothiourea organocatalyst are versatile intermediates in a range of enantioselective nucleophile‐dependent domino processes to form complex products of diverse topology with excellent stereoselectivity. Use of either 1,3‐dicarbonyls, acyl benzothiazoles, or acyl benzimidazoles as nucleophiles allows three distinct, diastereodivergent domino reaction pathways to be accessed to form various fused polycyclic cores containing multiple contiguous stereocentres.

Published
2016

232. pH controlled assembly of a self-complementary halogen-bonded dimer† †Electronic supplementary information (ESI) available: Details of computational methods, synthesis and characterisation data for all compounds are provided. CCDC 1488032–1488035. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc03696a Click here for additional data file. Click here for additional data file

Author

Maugeri, Leonardo, Jamieson, Ellen M. G., Cordes, David B., Slawin, Alexandra M. Z., and Philp, Douglas

Subjects
inorganic chemicals, Chemistry, fungi, food and beverages
Abstract

Halogen bonding between an oxygen acceptor and an iodotriazole donor can be switched on an off by cycling the solution pH., Phenols and their corresponding phenoxide anions can form halogen bonds with neutral iodotriazoles. The strength of these interactions depends critically on the protonation state of the oxygen atom – the interaction of the phenoxide anion is more than an order of magnitude stronger than the corresponding phenol. The assembly of a molecule bearing both an iodotriazole and a phenoxide anion into a self-complementary dimer, stabilised by two halogen bonds between the phenoxide anions and the neutral iodotriazoles has been demonstrated. The corresponding phenol shows no halogen bond mediated assembly either in the solid or in the solution state. This assembly process can be actuated simply by a change in protonation state – treatment of the phenol with one equivalent of base results in deprotonation and assembly of the dimer. The structure of the homodimer formed by the phenoxide-bearing iodotriazole has been determined in the solid state and 19F NMR spectroscopy demonstrates that the assembled dimer persists in solution and that it has significant stability. 19F NMR spectroscopy has also been used to demonstrate that the assembly process is completely reversible.

Published
2016

233. Solution-Processable Silicon Phthalocyanines in Electroluminescent and Photovoltaic Devices

Author

Zysman-Colman, Eli, Ghosh, Sanjay S., Xie, Guohua, Varghese, Shinto, Chowdhury, Mithun, Sharma, Nidhi, Cordes, David B., Slawin, Alexandra M. Z., and Samuel, Ifor D. W.

Subjects
near-IR emission, organic solar cells, solution-processable organic light-emitting diodes, single crystals, Research Article, silicon phthalocyanines
Abstract

Phthalocyanines and their main group and metal complexes are important classes of organic semiconductor materials but are usually highly insoluble and so frequently need to be processed by vacuum deposition in devices. We report two highly soluble silicon phthalocyanine (SiPc) diester compounds and demonstrate their potential as organic semiconductor materials. Near-infrared (λ(EL) = 698-709 nm) solution-processed organic light-emitting diodes (OLEDs) were fabricated and exhibited external quantum efficiencies (EQEs) of up to 1.4%. Binary bulk heterojunction solar cells employing P3HT or PTB7 as the donor and the SiPc as the acceptor provided power conversion efficiencies (PCE) of up to 2.7% under simulated solar illumination. Our results show that soluble SiPcs are promising materials for organic electronics.

Published
2016

234. The literate-programming paradigm

Author

Cordes, David and Brown, Marcus

Subjects
Program Development Techniques, Programming Language, Software Quality, Coding
Published
1991

235. Janus All‐Cis 2,3,4,5,6‐Pentafluorocyclohexyl Building Blocks Applied to Medicinal Chemistry and Bioactives Discovery Chemistry.

Author

Clark, Joshua L., Neyyappadath, Rifahath M., Yu, Cihang, Slawin, Alexandra M. Z., Cordes, David B., and O'Hagan, David

Subjects
PHARMACEUTICAL chemistry, METHYL formate, FUNCTIONAL groups, AMINO acids, ORGANIC chemistry, ALCOHOL, CATALYSTS, HYDROGENATION
Abstract

Monoalkylated derivatives of the unusually polar all‐cis 2,3,4,5,6‐ pentafluorocyclohexyl (Janus face) motif are prepared starting from an aryl hydrogenation of 2,3,4,5,6‐ pentafluorophenylacetate methyl ester 15. The method used Zeng's Rh(CAAC) carbene catalyst 4 in the hydrogenation following the protocol developed by Glorius. The resultant Janus pentafluorocyclohexylacetate methyl ester 16 was converted to the corresponding alcohol 18, aldehyde 13, bromide 29 and azide 14 through functional group manipulations, and some of these building blocks were used in Ugi‐multicomponent and Cu‐catalysed click reactions. NBoc protected pentafluoroarylphenylalanine methyl ester 35 was also subject to an aryl hydrogenation, and then deprotection to generate the Janus face β‐pentafluorocyclohexyl‐alanine amino acid 15, which was incorporated into representative members of an emerging class of candidate antiviral compounds. Log P measurements demonstrate that the all‐cis 2,3,4,5,6‐pentafluorocyclohexyl ring system is more polar than a phenyl ring. In overview the paper introduces new building blocks containing this Janus ring and demonstrates their progression to molecules typically used in bioactives discovery programmes. [ABSTRACT FROM AUTHOR]

Published
2021
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238. A Simplified Extractive Metallurgy Exercise to Demonstrate Selective Extraction of Copper

Author

Smellie, Iain A., primary, Abdelhamid, Yusra, additional, Carpenter-Warren, Cameron L., additional, Cordes, David B., additional, Elliott, Clement, additional, Lamorte, Sarah, additional, Patterson, Iain L. J., additional, Sanders, William, additional, Sandison, Iain P., additional, Slawin, Alexandra M. Z., additional, Stewart, Dominic M., additional, and Walters, Samuel N., additional

Published
2020
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240. Exciton efficiency beyond the spin statistical limit in organic light emitting diodes based on anthracene derivatives

Author

Sharma, Nidhi, primary, Wong, Michael Yin, additional, Hall, David, additional, Spuling, Eduard, additional, Tenopala-Carmona, Francisco, additional, Privitera, Alberto, additional, Copley, Graeme, additional, Cordes, David B., additional, Slawin, Alexandra M. Z., additional, Murawski, Caroline, additional, Gather, Malte C., additional, Beljonne, David, additional, Olivier, Yoann, additional, Samuel, Ifor D. W., additional, and Zysman-Colman, Eli, additional

Published
2020
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242. Ligand electronic fine-tuning and its repercussion on the photocatalytic activity and mechanistic pathways of the copper-photocatalysed aza-Henry reaction

Author

Li, Chenfei, primary, Dickson, Robert, additional, Rockstroh, Nils, additional, Rabeah, Jabor, additional, Cordes, David B., additional, Slawin, Alexandra M. Z., additional, Hünemörder, Paul, additional, Spannenberg, Anke, additional, Bühl, Michael, additional, Mejía, Esteban, additional, Zysman-Colman, Eli, additional, and Kamer, Paul C. J., additional

Published
2020
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246. Improving Processability and Efficiency of Resonant TADF Emitters: A Design Strategy

Author

Hall, David, primary, Suresh, Subeesh Madayanad, additional, dos Santos, Paloma L., additional, Duda, Eimantas, additional, Bagnich, Sergey, additional, Pershin, Anton, additional, Rajamalli, Pachaiyappan, additional, Cordes, David B., additional, Slawin, Alexandra M. Z., additional, Beljonne, David, additional, Köhler, Anna, additional, Samuel, Ifor D. W., additional, Olivier, Yoann, additional, and Zysman‐Colman, Eli, additional

Published
2019
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248. Bipyridine‐Containing Host Materials for High Performance Yellow Thermally Activated Delayed Fluorescence‐Based Organic Light Emitting Diodes with Very Low Efficiency Roll‐Off

Author

Chen, Dongyang, primary, Rajamalli, Pachaiyappan, additional, Tenopala‐Carmona, Francisco, additional, Carpenter‐Warren, Cameron L., additional, Cordes, David B., additional, Keum, Chang‐Min, additional, Slawin, Alexandra M. Z., additional, Gather, Malte C., additional, and Zysman‐Colman, Eli, additional

Published
2019
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249. Use of Pyrimidine and Pyrazine Bridges as a Design Strategy To Improve the Performance of Thermally Activated Delayed Fluorescence Organic Light Emitting Diodes

Author

dos Santos, Paloma Lays, primary, Chen, Dongyang, additional, Rajamalli, Pachaiyappan, additional, Matulaitis, Tomas, additional, Cordes, David B., additional, Slawin, Alexandra M. Z., additional, Jacquemin, Denis, additional, Zysman-Colman, Eli, additional, and Samuel, Ifor D. W., additional

Published
2019
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