ORCID Profile
0000-0003-0594-4193
Current Organisation
Royal College of Surgeons in Ireland
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Publisher: American Chemical Society (ACS)
Date: 25-07-2013
DOI: 10.1021/JO401326F
Abstract: The use of an inorganic oxidant with an acetic acid/acetonitrile solvent combination has been identified as optimal for direct arene/1,2-disubstituted alkene oxidative couplings, providing an efficient route to trisubstituted alkenes. The acetonitrile cosolvent dramatically accelerates the rate of reaction, and an insoluble inorganic oxidant limits unwanted oxidation of substrates. The scope of this procedure is illustrated with arenes and alkenes containing electron-donating and -withdrawing substituents resulting in a general synthetic strategy to trisubstituted alkenes. In situ ESI-MS analysis of the reaction components has identified the key Pd intermediates in the Fujiwara-Moritani catalytic cycle.
Publisher: Elsevier BV
Date: 08-2010
Publisher: AIP Publishing
Date: 21-09-2006
DOI: 10.1063/1.2353112
Abstract: The influence of an applied microwave field on the dynamics of methylamine-dichloromethane (DCM) mixtures bound within atactic polystyrene (a-PS) over a range of polymer densities from 30to94wt% polymer was examined using atomistic molecular dynamics simulations. This study is an extension of previous studies on methylamine transport in relatively polar polystyrene solutions of methanol and dimethylformamide [M. J. Purdue et al., J. Chem. Phys. 124, 204904 (2006)]. A direct comparison is made across the three types of polystyrene solutions. Consideration is given to both solvent and reagent transport within the polymer solutions under zero-field conditions and in an external electromagnetic field in the canonical ensemble (NVT) at 298.0K. Various frequencies up to 104GHz and a rms electric field intensity of 0.1V∕Å were applied. The simulation studies were validated by comparison of the simulated zero-field self-diffusion coefficients of DCM in a-PS with those obtained using pulsed-gradient spin-echo NMR spectrometry. Athermal effects of microwave fields on solute transport behavior within polymer solutions are discussed.
Publisher: AIP Publishing
Date: 22-05-2006
DOI: 10.1063/1.2197496
Abstract: Equilibrium and nonequilibrium molecular dynamics simulation techniques were used to assess the influence of an applied microwave field on the dynamics of methylamine-methanol and methylamine-dimethylformamide (DMF) solutions bound within atactic polystyrene over a range of polymer densities from 35to96wt% polymer. Atomistically detailed systems were studied, ranging from 3000 to 10 644 particles, using previously established potential models. Structural and dynamical properties were determined in the canonical (NVT) ensemble at 298K. The simulated DMF self-diffusion coefficients in polystyrene solutions were compared with the zero-field experimental results established with pulsed-gradient spin-echo NMR spectrometry. A simulated external microwave field, with a rms electric field intensity of 0.1V∕Å, was applied to these systems and the simulated dynamical results over field frequencies up to 104GHz were compared with the zero-field values. Simulated evidence of athermal effects on the diffusive characteristics of these mixtures is reported.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9SC02197C
Abstract: The tumour switches on the NIR-AZA emission for fluorescence guided surgery.
Publisher: Springer Science and Business Media LLC
Date: 19-04-2005
Publisher: American Chemical Society (ACS)
Date: 10-08-2004
DOI: 10.1021/JA047649E
Abstract: Photodynamic therapy (PDT) is an emerging treatment modality for a range of disease classes, both cancerous and noncancerous. This has brought about an active pursuit of new PDT agents that can be optimized for the unique set of photophysical characteristics that are required for a successful clinical agent. We now describe a totally new class of PDT agent, the BF2-chelated 3,5-diaryl-1H-pyrrol-2-yl-3,5-diarylpyrrol-2-ylideneamines (tetraarylazadipyrromethenes). Optimized synthetic procedures have been developed to facilitate the generation of an array of specifically substituted derivatives to demonstrate how control of key therapeutic parameters such as wavelength of maximum absorbance and singlet-oxygen generation can be achieved. Photosensitizer absorption maxima can be varied within the body's therapeutic window between 650 and 700 nm, with high extinction coefficients ranging from 75,000 to 85,000 M(-1) cm(-1). Photosensitizer singlet-oxygen generation level was modulated by the exploitation of the heavy-atom effect. An array of photosensitizers with and without bromine atom substituents gave rise to a series of compounds with varying singlet-oxygen generation profiles. X-ray structural evidence indicates that the substitution of the bromine atoms has not caused a planarity distortion of the photosensitizer. Comparative singlet-oxygen production levels of each photosensitizer versus two standards demonstrated a modulating effect on singlet-oxygen generation depending upon substituent patterns about the photosensitizer. Confocal laser scanning microscopy imaging of 18a in HeLa cervical carcinoma cells proved that the photosensitizer was exclusively localized to the cellular cytoplasm. In vitro light-induced toxicity assays in HeLa cervical carcinoma and MRC5-SV40 transformed fibroblast cancer cell lines confirmed that the heavy-atom effect is viable in a live cellular system and that it can be exploited to modulate assay efficacy. Direct comparison of the efficacy of the photosensitizers 18b and 19b, which only differ in molecular structure by the presence of two bromine atoms, illustrated an increase in efficacy of more than a 1000-fold in both cell lines. All photosensitizers have very low to nondeterminable dark toxicity in our assay system.
Publisher: Wiley
Date: 09-2008
Publisher: International Union of Crystallography (IUCr)
Date: 09-01-2014
DOI: 10.1107/S2053229614000084
Abstract: The structural chemistry of the title compound, [Pd(C 32 H 22 N 3 ) 2 ], at 173 K is described. The compound is comprised of two deprotonated (3,5-diphenyl-1 H -pyrrol-2-yl)(3,5-diphenylpyrrol-2-ylidene)amine ligands coordinated to a central Pd II cation, which lies on an inversion centre and has distorted square-planar geometry. The Pd—N bond lengths range from 2.008 (4) to 2.014 (4) Å and the bite angle is 84.16 (14)°. The chelate plane makes a dihedral angle of 45.3 (2)° with respect to the central PdN 4 plane, giving a stepped conformation to the molecule. The complex displays simple intramolecular C—H...N hydrogen bonds, while the unit cell consists of discrete monomeric Pd(C 32 H 22 N 3 ) 2 units which display intermolecular C—H...π interactions and limited intra- and intermolecular π–π stacking.
Publisher: Elsevier BV
Date: 04-2018
Publisher: Elsevier BV
Date: 03-2011
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Donal O'Shea.