John Goodby | University of York (original) (raw)
Papers by John Goodby
Liquid Crystals, Nov 25, 2014
All chemicals were used as received, without purification with the exception of bromobenzene, whi... more All chemicals were used as received, without purification with the exception of bromobenzene, which was distilled prior to use. Column chromatography was performed using Fluka 70-230 silica gel, dry vacuum flash chromatography (DVFC) [S1] was performed using Merck 15111 silica gel. Solvents were dried by passage through a column of activated alumina prior to use. NMR spectra were recorded on a JEOL ECX spectrometer operating at 400 MHz ( 1 H) or 100.5 MHz ( 13 C), with the residual protic solvent used as the internal standard in all cases. Mass spectra were recorded on a Bruker micrOTOF MS-Agilent series 1200LC spectrometer (ESI) or a Waters GCT Premier mass spectrometer (EI). FTIR spectroscopy was performed using a Shimadzu IR Prestige-21 with Specac Golden Gate diamond ATR IR insert. High-performance liquid chromatography was performed on a Shimadzu Prominence modular HPLC system comprising a LC-20A liquid chromatograph, a DGU-20A5 and DGU-20B degasser, a SIL-20A autosampler, a CBM-20A communication bus, a CTO-20A column oven, and a SPO-20A dual wavelength UV-vis detector. The column used was an Alltech C18 bonded reverse-phase silica column with a 5 μm pore size, an internal diameter of 10 mm and a length of 250 mm, acetonitrile was used as the mobile phase in each case. Polarised optical microscopy was performed on a Zeiss Axioskop 40Pol microscope using a Mettler FP82HT hotstage controlled by a Mettler FP90 central processor. Photomicrographs were captured with aid of an InfinityX-21 MP digital camera. Differential scanning calorimetry was performed on a Mettler DSC822 e fitted with an autosampler operating with Mettler Star e software and calibrated before use each day using an indium standard (onset = 156.55 ± 0.2 °C, ΔH = 28.45 ± 0.40 Jg -1 ) under an atmosphere of dry nitrogen. Computational studies were performed using GAMESS-UK [S2] for ab initio calculations (B3LYP and MP2) and MOPAC 2012 [S3] for semi-empirical calculations (AM1, PM6). A catalytic quantity of DMF (0.1 ml) was added to a stirred suspension of pimelic acid (i1 -1, 17.5 g, 0.109 mmol) and oxalyl chloride (40 g, 27 ml, 0.32 mol) in anhydrous DCM (300 ml) under an atmosphere of dry argon resulting in the vigorous evolution of gas. The reaction was monitored by the evolution of gas, and was stirred for a further 30 minutes after the cessation of effervescence, at which point the solvent and excess oxalyl chloride was removed in vacuo. The crude pimeloyl chloride obtained (i1 -2) was added dropwise to a stirred, cooled (0 °C) suspension of aluminium chloride (42.6 g, 0.32 mmol) and anisole (34.6 g, 35 ml, 0.32 mol) in anhydrous DCM (500 ml) under an atmosphere of dry argon. The pimeloyl chloride was added at such a rate that the temperature of the reaction did not exceed 5 °C. The reaction was stirred overnight and quenched by pouring onto ice. The organic layer was separated and washed with sodium hydroxide (2 M, 2 x 200 ml), water (2 x 100 ml) and brine (2 x 200 ml) and dried over anhydrous MgSO4. The excess anisole present was removed by azeotropic distillation with xylene (2 x 200 ml), toluene (2 x 200 ml) and finally hexanes (3 x 200 ml). The resulting product was crystallized from 9:1 DMF/H2O to give the title compound as off white plates.
Molecular crystals and liquid crystals science technology. Section A, Molecular crystals and liquid crystals (CD-ROM), Aug 1, 1999
ABSTRACT Three homologous series of 6-Z-n-alkyl-α-D-galactopyranoses, where Z represents either a... more ABSTRACT Three homologous series of 6-Z-n-alkyl-α-D-galactopyranoses, where Z represents either a carboxy group (OCO), a sulphur atom (S) or an oxypropylthio group (OC3H6S) have been synthesised starting from 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose in either two or three steps. The synthesis of the fourth series of6-O-n-alkyl-α-D-galactopyranoses (Z = O) has already been reported. The length of the terminal aliphatic chains has been varied systematically and the effect on the thermotropic liquid crystal transition temperatures prepared. An enantiotropic smectic A* phase was found for all of the homologues studied. The order of efficiency of the linking group Z in favouring liquid crystal formation for the same homologues of the 6-Z-n-alkyl-α-D-galactopyranoses is S = OCO > O > OC3H6S.
Wiley-VCH Verlag GmbH eBooks, Apr 8, 2008
![Research paper thumbnail of Publisher’s Note: Molecular orientation and the infrared dichroism of a chiral smectic liquid crystal in a homogeneously aligned cell at different temperature and bias fields [Phys. Rev. E68, 031707 (2003)]](https://attachments.academia-assets.com/118509466/thumbnails/1.jpg)
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Physical chemistry chemical physics : PCCP, Jan 21, 2016
An assessment of five different definitions of the principal molecular axis along which molecules... more An assessment of five different definitions of the principal molecular axis along which molecules align in a nematic liquid crystal system has been made by analysing fully atomistic molecular dynamics (MD) simulations of a set of anthraquinone dyes in the cyanobiphenyl-based nematic host mixture E7. Principal molecular axes of the dyes defined by minimum moment of inertia, minimum circumference, minimum area, maximum aspect ratio, and surface tensor models were tested, and the surface tensor model was found to give the best description. Analyses of MD simulations of E7 alone showed that the surface tensor model also gave a good description of the principal molecular axes of the host molecules, suggesting that this model may be applicable more generally. Calculated dichroic order parameters of the guest-host systems were obtained by combining the surface tensor analysis with fixed transition dipole moment (TDM) orientations from time-dependent density functional theory (TD-DFT) calcu...
Physical Review A
ABSTRACT
Biomaterials, 2010
The synthesis and characterisation of a series of liquid-crystalline aromaticealiphatic copolyest... more The synthesis and characterisation of a series of liquid-crystalline aromaticealiphatic copolyesters are presented. Differential scanning calorimetry showed these polymers have a glass transition temperature in the range 72 Ce116 C. Polarised optical microscopy showed each polymer exhibits a nematic mesophase on heating to the molten state at temperatures below 165 C. Melt processing is demonstrated by the production of injection moulded and compression moulded specimens with Young's modulus of 5.7 AE 0.3 GPa and 2.3 AE 0.3 GPa, respectively. Wide-angle X-ray scattering data showed molecular orientation is responsible for the increase of mechanical properties along the injection direction. Degradation studies in the temperature range 37 Ce80 C are presented for one polymer of this series and a kinetic constant of 0.002 days À1 is obtained at 37 C assuming a first order reaction. The activation energy (83.4 kJ mol À1) is obtained following the Arrhenius analysis of degradation, showing degradation of this material is less temperature sensitive compared with other commercially available biodegradable polyesters. In vitro and in vivo biocompatibility data are presented and it is shown the unique combination of degradative, mechanical and biological properties of these polymers may represent in the future an alternative for medical device manufacturers.
Radiotherapy and Oncology, 2012
Purpose/Objective: The purpose of this work is to test a commercial plastic scintillation detecto... more Purpose/Objective: The purpose of this work is to test a commercial plastic scintillation detector (PSD) prototype and compare its performance with common clinical dosimeters. We verified the overall accuracy, the precision and the capacity to resolve the scintillation signal from the parasitic Cerenkov light. Materials and Methods: The sensitive volume of the PSD is approximately 1 by 3 mm, the optical output is read with a photodiode. We first tested the detector linearity. Then output factors, depth dose curves, tissue-maximum ratio (TMR) and lateral profiles with two detector orientations were measured for both photon and electron beams. Comparisons were made with a large and small volume ion chambers as well as with diodes. Results: Detector precision was excellent, and the measured uncertainty was typically below 0.4%. The detector response was linear from doses between 0.4 Gy and 10 Gy. Changes in the instantaneous dose rate of up to 100% did not affect the readings. TMR and depth dose showed differences less than 0.5 % between PSD and ionization chamber. Figure 1, shows a sample profile (scan in the crossline direction and two PSD orientations). Excellent agreement is seen between the PSD and the miniature ionization chamber (A16). When the detector orientation is crossline, there is a high variation of Cerenkov light. Nevertheless, the symmetry of the measured profiles proves the effectiveness of the Cerenkov subtraction method. Table 1, presents output factor measurements for the PSD and an ion chamber.
Helvetica Chimica Acta, Jun 12, 2023
Journal of Carbohydrate Chemistry, Mar 1, 2007
The coupling reaction of 3,4,6‐tri‐O‐acetyl‐α‐d‐glucopyranoside 2‐O‐lactone 1 (α‐CMGL) with two k... more The coupling reaction of 3,4,6‐tri‐O‐acetyl‐α‐d‐glucopyranoside 2‐O‐lactone 1 (α‐CMGL) with two kinds of lipophilic amines, aminosteroids and fatty amines, efficiently yielded, after deprotection, the corresponding free α‐glucolipid amides. The latter family of compounds exhibited good thermal stability, allowing the higher homologs having longer linear fatty chains or saturated steroids to possess lamellar smectic A phases.
ChemInform, Jan 30, 2001
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Journal of Materials Chemistry, 1998
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, 1997
Novel optically active dopants for smectic C devices incorporating a 2, 4-disubstituted oxazoline... more Novel optically active dopants for smectic C devices incorporating a 2, 4-disubstituted oxazoline ring have been prepared from readily available starting materials. We report the observation of highly frustrated phase behaviour when these materials are added to a smectic C and nematic host, depending upon the degree of branching at the terminal chain adjacent to the chiral centre and the
Liquid Crystals, Oct 3, 2016
Physical Review Letters, 1981
W. Kerner et al. , in Proceedings of the Ninth Euro pean Conference on Cont+oiled Eusion and Plasma
The journal of physical chemistry. B, Jan 19, 2015
The relationship between molecular association and re-entrant phase behavior in polar calamitic l... more The relationship between molecular association and re-entrant phase behavior in polar calamitic liquid crystals has been explored in two families of materials: the 4'-alkoxy-4-cyanobiphenyls (6OCB and 8OCB) and the 4'-alkoxy-4-nitrobiphenyls. Although re-entrant nematic phase behavior has previously been observed in the phase diagram of 6OCB/8OCB, this is not observed in mixtures of the analogous nitro materials. As there is no stabilization of the smectic A phase in mixture studies, it was conjectured that the degree of association for the nitro systems is greater than that for the cyano analogues. This hypothesis was tested by using measured dielectric anisotropies and computed molecular properties to obtain a value of the Kirkwood factor, g, which describes the degree of association of dipoles in a liquid. These computed values of g confirm that the degree of association for nitro materials is greater than that for cyano and offer a useful method for quantifying molecular...
Liquid Crystals, Nov 25, 2014
All chemicals were used as received, without purification with the exception of bromobenzene, whi... more All chemicals were used as received, without purification with the exception of bromobenzene, which was distilled prior to use. Column chromatography was performed using Fluka 70-230 silica gel, dry vacuum flash chromatography (DVFC) [S1] was performed using Merck 15111 silica gel. Solvents were dried by passage through a column of activated alumina prior to use. NMR spectra were recorded on a JEOL ECX spectrometer operating at 400 MHz ( 1 H) or 100.5 MHz ( 13 C), with the residual protic solvent used as the internal standard in all cases. Mass spectra were recorded on a Bruker micrOTOF MS-Agilent series 1200LC spectrometer (ESI) or a Waters GCT Premier mass spectrometer (EI). FTIR spectroscopy was performed using a Shimadzu IR Prestige-21 with Specac Golden Gate diamond ATR IR insert. High-performance liquid chromatography was performed on a Shimadzu Prominence modular HPLC system comprising a LC-20A liquid chromatograph, a DGU-20A5 and DGU-20B degasser, a SIL-20A autosampler, a CBM-20A communication bus, a CTO-20A column oven, and a SPO-20A dual wavelength UV-vis detector. The column used was an Alltech C18 bonded reverse-phase silica column with a 5 μm pore size, an internal diameter of 10 mm and a length of 250 mm, acetonitrile was used as the mobile phase in each case. Polarised optical microscopy was performed on a Zeiss Axioskop 40Pol microscope using a Mettler FP82HT hotstage controlled by a Mettler FP90 central processor. Photomicrographs were captured with aid of an InfinityX-21 MP digital camera. Differential scanning calorimetry was performed on a Mettler DSC822 e fitted with an autosampler operating with Mettler Star e software and calibrated before use each day using an indium standard (onset = 156.55 ± 0.2 °C, ΔH = 28.45 ± 0.40 Jg -1 ) under an atmosphere of dry nitrogen. Computational studies were performed using GAMESS-UK [S2] for ab initio calculations (B3LYP and MP2) and MOPAC 2012 [S3] for semi-empirical calculations (AM1, PM6). A catalytic quantity of DMF (0.1 ml) was added to a stirred suspension of pimelic acid (i1 -1, 17.5 g, 0.109 mmol) and oxalyl chloride (40 g, 27 ml, 0.32 mol) in anhydrous DCM (300 ml) under an atmosphere of dry argon resulting in the vigorous evolution of gas. The reaction was monitored by the evolution of gas, and was stirred for a further 30 minutes after the cessation of effervescence, at which point the solvent and excess oxalyl chloride was removed in vacuo. The crude pimeloyl chloride obtained (i1 -2) was added dropwise to a stirred, cooled (0 °C) suspension of aluminium chloride (42.6 g, 0.32 mmol) and anisole (34.6 g, 35 ml, 0.32 mol) in anhydrous DCM (500 ml) under an atmosphere of dry argon. The pimeloyl chloride was added at such a rate that the temperature of the reaction did not exceed 5 °C. The reaction was stirred overnight and quenched by pouring onto ice. The organic layer was separated and washed with sodium hydroxide (2 M, 2 x 200 ml), water (2 x 100 ml) and brine (2 x 200 ml) and dried over anhydrous MgSO4. The excess anisole present was removed by azeotropic distillation with xylene (2 x 200 ml), toluene (2 x 200 ml) and finally hexanes (3 x 200 ml). The resulting product was crystallized from 9:1 DMF/H2O to give the title compound as off white plates.
Molecular crystals and liquid crystals science technology. Section A, Molecular crystals and liquid crystals (CD-ROM), Aug 1, 1999
ABSTRACT Three homologous series of 6-Z-n-alkyl-α-D-galactopyranoses, where Z represents either a... more ABSTRACT Three homologous series of 6-Z-n-alkyl-α-D-galactopyranoses, where Z represents either a carboxy group (OCO), a sulphur atom (S) or an oxypropylthio group (OC3H6S) have been synthesised starting from 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose in either two or three steps. The synthesis of the fourth series of6-O-n-alkyl-α-D-galactopyranoses (Z = O) has already been reported. The length of the terminal aliphatic chains has been varied systematically and the effect on the thermotropic liquid crystal transition temperatures prepared. An enantiotropic smectic A* phase was found for all of the homologues studied. The order of efficiency of the linking group Z in favouring liquid crystal formation for the same homologues of the 6-Z-n-alkyl-α-D-galactopyranoses is S = OCO > O > OC3H6S.
Wiley-VCH Verlag GmbH eBooks, Apr 8, 2008
Physical chemistry chemical physics : PCCP, Jan 21, 2016
An assessment of five different definitions of the principal molecular axis along which molecules... more An assessment of five different definitions of the principal molecular axis along which molecules align in a nematic liquid crystal system has been made by analysing fully atomistic molecular dynamics (MD) simulations of a set of anthraquinone dyes in the cyanobiphenyl-based nematic host mixture E7. Principal molecular axes of the dyes defined by minimum moment of inertia, minimum circumference, minimum area, maximum aspect ratio, and surface tensor models were tested, and the surface tensor model was found to give the best description. Analyses of MD simulations of E7 alone showed that the surface tensor model also gave a good description of the principal molecular axes of the host molecules, suggesting that this model may be applicable more generally. Calculated dichroic order parameters of the guest-host systems were obtained by combining the surface tensor analysis with fixed transition dipole moment (TDM) orientations from time-dependent density functional theory (TD-DFT) calcu...
Physical Review A
ABSTRACT
Biomaterials, 2010
The synthesis and characterisation of a series of liquid-crystalline aromaticealiphatic copolyest... more The synthesis and characterisation of a series of liquid-crystalline aromaticealiphatic copolyesters are presented. Differential scanning calorimetry showed these polymers have a glass transition temperature in the range 72 Ce116 C. Polarised optical microscopy showed each polymer exhibits a nematic mesophase on heating to the molten state at temperatures below 165 C. Melt processing is demonstrated by the production of injection moulded and compression moulded specimens with Young's modulus of 5.7 AE 0.3 GPa and 2.3 AE 0.3 GPa, respectively. Wide-angle X-ray scattering data showed molecular orientation is responsible for the increase of mechanical properties along the injection direction. Degradation studies in the temperature range 37 Ce80 C are presented for one polymer of this series and a kinetic constant of 0.002 days À1 is obtained at 37 C assuming a first order reaction. The activation energy (83.4 kJ mol À1) is obtained following the Arrhenius analysis of degradation, showing degradation of this material is less temperature sensitive compared with other commercially available biodegradable polyesters. In vitro and in vivo biocompatibility data are presented and it is shown the unique combination of degradative, mechanical and biological properties of these polymers may represent in the future an alternative for medical device manufacturers.
Radiotherapy and Oncology, 2012
Purpose/Objective: The purpose of this work is to test a commercial plastic scintillation detecto... more Purpose/Objective: The purpose of this work is to test a commercial plastic scintillation detector (PSD) prototype and compare its performance with common clinical dosimeters. We verified the overall accuracy, the precision and the capacity to resolve the scintillation signal from the parasitic Cerenkov light. Materials and Methods: The sensitive volume of the PSD is approximately 1 by 3 mm, the optical output is read with a photodiode. We first tested the detector linearity. Then output factors, depth dose curves, tissue-maximum ratio (TMR) and lateral profiles with two detector orientations were measured for both photon and electron beams. Comparisons were made with a large and small volume ion chambers as well as with diodes. Results: Detector precision was excellent, and the measured uncertainty was typically below 0.4%. The detector response was linear from doses between 0.4 Gy and 10 Gy. Changes in the instantaneous dose rate of up to 100% did not affect the readings. TMR and depth dose showed differences less than 0.5 % between PSD and ionization chamber. Figure 1, shows a sample profile (scan in the crossline direction and two PSD orientations). Excellent agreement is seen between the PSD and the miniature ionization chamber (A16). When the detector orientation is crossline, there is a high variation of Cerenkov light. Nevertheless, the symmetry of the measured profiles proves the effectiveness of the Cerenkov subtraction method. Table 1, presents output factor measurements for the PSD and an ion chamber.
Helvetica Chimica Acta, Jun 12, 2023
Journal of Carbohydrate Chemistry, Mar 1, 2007
The coupling reaction of 3,4,6‐tri‐O‐acetyl‐α‐d‐glucopyranoside 2‐O‐lactone 1 (α‐CMGL) with two k... more The coupling reaction of 3,4,6‐tri‐O‐acetyl‐α‐d‐glucopyranoside 2‐O‐lactone 1 (α‐CMGL) with two kinds of lipophilic amines, aminosteroids and fatty amines, efficiently yielded, after deprotection, the corresponding free α‐glucolipid amides. The latter family of compounds exhibited good thermal stability, allowing the higher homologs having longer linear fatty chains or saturated steroids to possess lamellar smectic A phases.
ChemInform, Jan 30, 2001
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Journal of Materials Chemistry, 1998
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, 1997
Novel optically active dopants for smectic C devices incorporating a 2, 4-disubstituted oxazoline... more Novel optically active dopants for smectic C devices incorporating a 2, 4-disubstituted oxazoline ring have been prepared from readily available starting materials. We report the observation of highly frustrated phase behaviour when these materials are added to a smectic C and nematic host, depending upon the degree of branching at the terminal chain adjacent to the chiral centre and the
Liquid Crystals, Oct 3, 2016
Physical Review Letters, 1981
W. Kerner et al. , in Proceedings of the Ninth Euro pean Conference on Cont+oiled Eusion and Plasma
The journal of physical chemistry. B, Jan 19, 2015
The relationship between molecular association and re-entrant phase behavior in polar calamitic l... more The relationship between molecular association and re-entrant phase behavior in polar calamitic liquid crystals has been explored in two families of materials: the 4'-alkoxy-4-cyanobiphenyls (6OCB and 8OCB) and the 4'-alkoxy-4-nitrobiphenyls. Although re-entrant nematic phase behavior has previously been observed in the phase diagram of 6OCB/8OCB, this is not observed in mixtures of the analogous nitro materials. As there is no stabilization of the smectic A phase in mixture studies, it was conjectured that the degree of association for the nitro systems is greater than that for the cyano analogues. This hypothesis was tested by using measured dielectric anisotropies and computed molecular properties to obtain a value of the Kirkwood factor, g, which describes the degree of association of dipoles in a liquid. These computed values of g confirm that the degree of association for nitro materials is greater than that for cyano and offer a useful method for quantifying molecular...