Paris Georghiou | Memorial University of Newfoundland (original) (raw)
Papers by Paris Georghiou
The Journal of Organic Chemistry, 2001
The first syntheses of the C3-symmetrical and unsymmetrical hexahomotrioxacalix[3]naphthalenes 3 ... more The first syntheses of the C3-symmetrical and unsymmetrical hexahomotrioxacalix[3]naphthalenes 3 and 4, respectively, and the corresponding tert-butyl hexahomotrioxacalix[3]naphthalene 3a are reported. A convergent synthesis of the linear hexahomotrimer precursors 19 and 19a is described, but the direct synthesis of 3 and 3a can also be achieved from the monomers 20 and 20a, respectively. A limited study of the binding properties of alkali-metal cations by 3 or 3a using a picrate-CHCl3 extraction showed only weak abilities to bind with the cations examined.
Synlett, 2005
Organic chemistry Z 0200 Calixnaphthalenes: Deep, Electron-Rich Naphthalene Ring-Containing Calix... more Organic chemistry Z 0200 Calixnaphthalenes: Deep, Electron-Rich Naphthalene Ring-Containing Calixarenes. The First Decade -[about 50 refs.]. -(GEORGHIOU*, P. E.; LI, Z.; ASHRAM, M.; CHOWDHURY, S.; MIZYED, S.; TRAN, A. H.; AL-SARAIERH, H.; MILLER, D. O.; Synlett 2005, 6, 879-891; Dep. Chem., Memorial Univ., St. John's, Newfoundland A1B 3X7, Can.; Eng.) -Lindner 31-225
Organic & Biomolecular Chemistry, 2003
The syntheses of the triesters formed between ethyl bromoacetate and hexahomotrioxacalix[3]naphth... more The syntheses of the triesters formed between ethyl bromoacetate and hexahomotrioxacalix[3]naphthalene 8, and its tert-butyl analogue 11, are described. Depending on the conditions employed, cone or partial cone conformers are produced. The conformations appear to have some influence on their complexation in neutral medium, with alkali metal cations. The X-ray structure of the partial cone triester 10 is presented.
Journal of the Chemical Society, Perkin Transactions 2, 2000
... Shehadeh Mizyeda, Paris E. Georghiou*a and Muhammad Ashramb. a Department of Chemistry, Memor... more ... Shehadeh Mizyeda, Paris E. Georghiou*a and Muhammad Ashramb. a Department of Chemistry, Memorial University of Newfoundland, St. ... Preliminary data obtained for the complexation of [60]fullerene (“C 60 ”) with the C 4 -symmetrical endo-calix[4]naphthalene 3 and its tert ...
![Research paper thumbnail of ChemInform Abstract: Thermodynamic Study of the Complexes of Calix[4]naphthalenes with [60]Fullerene in Different Solvents](https://attachments.academia-assets.com/43006829/thumbnails/1.jpg)
](Tetrahedron Letters, 1999
... a Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfound... more ... a Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfoundland, A1B 3X7, Canada. ... Li, Z.-P, "Synthesis and Properties of Calix[4]naphthalenes", Memorial University of Newfoundland, St.John's, Newfoundland, Canada, 1996.8. ...
![Research paper thumbnail of Supramolecular host–guest complexation of Lash's calix[4]azulene with tetraalkylammonium halides and tetrafluoroborate salts: binding and DFT computational studies](https://attachments.academia-assets.com/45136379/thumbnails/1.jpg)
](RSC Adv., 2015
azulene 1 is shown to be an effective molecular receptor for tetraalkylammonium halide and BF 4 À... more azulene 1 is shown to be an effective molecular receptor for tetraalkylammonium halide and BF 4 À salts. The respective binding constants were determined using global-fit analyses of the spectral data from UV-vis absorption titration studies. A DFT study of the putative complexes formed with 1, and the X-ray structure of 1 itself is also reported. † Electronic supplementary information (ESI) available: UV-vis titration; X-ray cif and checkcif les for 1 and .mol coordinates from DFT computations. CCDC [1049866]. For ESI and crystallographic data in CIF or other electronic format see
Journal of the Chemical Society, Perkin Transactions 1, 2002
![Research paper thumbnail of ChemInform Abstract: Synthesis of Calix[4]arene Triflates and Their Unusual Chemical Reactivity in Palladium-Catalyzed Reactions](https://attachments.academia-assets.com/45136400/thumbnails/1.jpg)
](
Synlett, 2005
Organic chemistry Z 0200 Calixnaphthalenes: Deep, Electron-Rich Naphthalene Ring-Containing Calix... more Organic chemistry Z 0200 Calixnaphthalenes: Deep, Electron-Rich Naphthalene Ring-Containing Calixarenes. The First Decade -[about 50 refs.]. -(GEORGHIOU*, P. E.; LI, Z.; ASHRAM, M.; CHOWDHURY, S.; MIZYED, S.; TRAN, A. H.; AL-SARAIERH, H.; MILLER, D. O.; Synlett 2005, 6, 879-891; Dep. Chem., Memorial Univ., St. John's, Newfoundland A1B 3X7, Can.; Eng.) -Lindner 31-225
Mutation Research Letters, 1989
It has been proposed that increases in the number of bacteria applied to each plate can enhance t... more It has been proposed that increases in the number of bacteria applied to each plate can enhance the sensitivity of the Ames S. typhimurium mutagenicity assay. These procedures have the potential to elevate the number of spontaneous revertants (SR) by increasing the contribution of pre-existing revertants (PER) present before application of the bacteria to the limited histidine test plates. We have investigated the contribution of PER when 10 9 bacteria are applied to the plates and found that the number of PER is dependent on the handling and storage of the cultures used to inoculate the overnight broth. The average number of PER/109 viable bacteria after overnight growth in broths inoculated from a frozen permanent, lyophilized permanent, master plate, and an isolated colony, of TA98 were 267, 188, 57 and 13 respectively. The resultant elevation of the number of SR for a strain may result in a failure to identify a mutagenic response. It is recommended that the number of PER be monitored in any modification of the Ames test that makes use of elevated numbers of bacteria.
Supramolecular Chemistry, 2015
![Research paper thumbnail of The first study about the relationship between the extractability of thiacalix[4]arene derivatives and the position of the coordination binding sites](https://attachments.academia-assets.com/45136378/thumbnails/1.jpg)
](Org. Biomol. Chem., 2015
Three organic ionophores (2-4) based on the p-tert-butylthiacalix[4]arene backbone, blocked in th... more Three organic ionophores (2-4) based on the p-tert-butylthiacalix[4]arene backbone, blocked in the 1,3alternate conformation, bearing two pyridyl coordinating moieties (ortho for 2, meta for 3 and para for 4), have been synthesized and characterized in the solid state. The solvent extraction experiments with the metal ions showed that the ability of these derivatives to complex with Ag + appeared to be largely dependent on the position of the nitrogen atoms of the pyridyl ring. Two different complexation modes have been confirmed by 1 H NMR titration. Ionophore 2 armed with two pyridyl moieties, complexed with Ag + cation through N⋯Ag + ⋯S interactions; however, ionophore 3 and ionophore 4 complexed with Ag + through metal-nitrogen (N⋯Ag + ) interactions. The DFT computational studies were consistent with the experimental findings. These findings will provide us with an important rule to design an appropriate thiacalix[4]arene ionophore in the future. Another study on the possibility for application of ionophores 2-4 for the treatment of waste water containing Cr(VI) and Cr(III), showed that ionophore 3 was useful in the application of the solvent extraction method in selective treatment of waste water containing Cr(VI) and Cr(III) prior to discharge. † Electronic supplementary information (ESI) available: Details of single-crystal X-ray crystallographic data. 1 H, 13 C NMR, MS and IR spectra of 3, computational study of 2-4 with Ag + . CCDC 1021161. For ESI and crystallographic data in CIF or other electronic format see
Studies in Natural Products Chemistry, 2012
Tetrahedron Letters, 2010
The enantioselective synthesis of each of the enantiomers of N-norlaudanidine, a minor Papaver so... more The enantioselective synthesis of each of the enantiomers of N-norlaudanidine, a minor Papaver somniferum opium benzyltetrahydoisoquinoline alkaloid is described. This was achieved using a chiral auxiliarymediated Bischler-Napieralski cyclization-sodium borohydride reduction strategy. The X-ray crystal structures of each of these secondary amines are reported.
![Research paper thumbnail of Synthesis of a cone-conformer bimodal calix[4]arene-crown-5 which forms a sensitive cesium ion sensing layer on gold-coated microcantilevers](https://attachments.academia-assets.com/45136371/thumbnails/1.jpg)
](New J. Chem., 2014
A ''bimodal'' or upper-and lower-rim functionalized ''calix-crown-5'' reported herein was unexpec... more A ''bimodal'' or upper-and lower-rim functionalized ''calix-crown-5'' reported herein was unexpectedly formed preferentially in a cone conformation. This was confirmed both by NMR spectroscopy and by single-crystal X-ray crystallography. The thioacetate functionalities on the new calix-crown-5 enabled it to form stable SAMs on the Au surface of a microcantilever, and a sensitive cesium ion sensor. Fig. 1 Structures of cone-1 and 1,3-alternate-2.
![Research paper thumbnail of Detection of calcium ions using gold-coated micro-cantilever sensors using upper- and lower-rim functionalized calix[4]arenes](https://attachments.academia-assets.com/45136457/thumbnails/1.jpg)
](Sensors and Actuators B: Chemical, 2014
The use of a bimodal calix[4]arene 2, was investigated as a potential host/guest sensing layer fo... more The use of a bimodal calix[4]arene 2, was investigated as a potential host/guest sensing layer for microcantilever sensors for detecting selected ions in dilute aqueous solutions. It was found that the sensing layers gave the highest microcantilever sensitivity when microcantilevers coated with 5 nm of Inconel and 40 nm of Au were incubated for 1 h in a 1.0 M dichloromethane:ethanol (1:9) solution of calix[4]arene 2. This calix[4]arene 2 was observed to form well-ordered self-assembled monolayers (SAM) on Au-coated substrates with no sign of bare areas or etch pits. Microcantilever sensor measurements showed that the calix[4]arene 2-functionalized cantilevers were able to detect Ca 2+ ions in aqueous solutions of CaCl 2 at concentrations as low as 10 −12 M. Although this receptor was shown to have a high affinity for CaCl 2 in aqueous solutions, it was also found to be able to detect other ionic compounds, however only producing microcantilever deflections ranging from 10% to 30% of those obtained for CaCl 2 .
The Journal of Organic Chemistry, 2001
The first syntheses of the C3-symmetrical and unsymmetrical hexahomotrioxacalix[3]naphthalenes 3 ... more The first syntheses of the C3-symmetrical and unsymmetrical hexahomotrioxacalix[3]naphthalenes 3 and 4, respectively, and the corresponding tert-butyl hexahomotrioxacalix[3]naphthalene 3a are reported. A convergent synthesis of the linear hexahomotrimer precursors 19 and 19a is described, but the direct synthesis of 3 and 3a can also be achieved from the monomers 20 and 20a, respectively. A limited study of the binding properties of alkali-metal cations by 3 or 3a using a picrate-CHCl3 extraction showed only weak abilities to bind with the cations examined.
Synlett, 2005
Organic chemistry Z 0200 Calixnaphthalenes: Deep, Electron-Rich Naphthalene Ring-Containing Calix... more Organic chemistry Z 0200 Calixnaphthalenes: Deep, Electron-Rich Naphthalene Ring-Containing Calixarenes. The First Decade -[about 50 refs.]. -(GEORGHIOU*, P. E.; LI, Z.; ASHRAM, M.; CHOWDHURY, S.; MIZYED, S.; TRAN, A. H.; AL-SARAIERH, H.; MILLER, D. O.; Synlett 2005, 6, 879-891; Dep. Chem., Memorial Univ., St. John's, Newfoundland A1B 3X7, Can.; Eng.) -Lindner 31-225
Organic & Biomolecular Chemistry, 2003
The syntheses of the triesters formed between ethyl bromoacetate and hexahomotrioxacalix[3]naphth... more The syntheses of the triesters formed between ethyl bromoacetate and hexahomotrioxacalix[3]naphthalene 8, and its tert-butyl analogue 11, are described. Depending on the conditions employed, cone or partial cone conformers are produced. The conformations appear to have some influence on their complexation in neutral medium, with alkali metal cations. The X-ray structure of the partial cone triester 10 is presented.
Journal of the Chemical Society, Perkin Transactions 2, 2000
... Shehadeh Mizyeda, Paris E. Georghiou*a and Muhammad Ashramb. a Department of Chemistry, Memor... more ... Shehadeh Mizyeda, Paris E. Georghiou*a and Muhammad Ashramb. a Department of Chemistry, Memorial University of Newfoundland, St. ... Preliminary data obtained for the complexation of [60]fullerene (“C 60 ”) with the C 4 -symmetrical endo-calix[4]naphthalene 3 and its tert ...
Tetrahedron Letters, 1999
... a Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfound... more ... a Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfoundland, A1B 3X7, Canada. ... Li, Z.-P, "Synthesis and Properties of Calix[4]naphthalenes", Memorial University of Newfoundland, St.John's, Newfoundland, Canada, 1996.8. ...
RSC Adv., 2015
azulene 1 is shown to be an effective molecular receptor for tetraalkylammonium halide and BF 4 À... more azulene 1 is shown to be an effective molecular receptor for tetraalkylammonium halide and BF 4 À salts. The respective binding constants were determined using global-fit analyses of the spectral data from UV-vis absorption titration studies. A DFT study of the putative complexes formed with 1, and the X-ray structure of 1 itself is also reported. † Electronic supplementary information (ESI) available: UV-vis titration; X-ray cif and checkcif les for 1 and .mol coordinates from DFT computations. CCDC [1049866]. For ESI and crystallographic data in CIF or other electronic format see
Journal of the Chemical Society, Perkin Transactions 1, 2002
Synlett, 2005
Organic chemistry Z 0200 Calixnaphthalenes: Deep, Electron-Rich Naphthalene Ring-Containing Calix... more Organic chemistry Z 0200 Calixnaphthalenes: Deep, Electron-Rich Naphthalene Ring-Containing Calixarenes. The First Decade -[about 50 refs.]. -(GEORGHIOU*, P. E.; LI, Z.; ASHRAM, M.; CHOWDHURY, S.; MIZYED, S.; TRAN, A. H.; AL-SARAIERH, H.; MILLER, D. O.; Synlett 2005, 6, 879-891; Dep. Chem., Memorial Univ., St. John's, Newfoundland A1B 3X7, Can.; Eng.) -Lindner 31-225
Mutation Research Letters, 1989
It has been proposed that increases in the number of bacteria applied to each plate can enhance t... more It has been proposed that increases in the number of bacteria applied to each plate can enhance the sensitivity of the Ames S. typhimurium mutagenicity assay. These procedures have the potential to elevate the number of spontaneous revertants (SR) by increasing the contribution of pre-existing revertants (PER) present before application of the bacteria to the limited histidine test plates. We have investigated the contribution of PER when 10 9 bacteria are applied to the plates and found that the number of PER is dependent on the handling and storage of the cultures used to inoculate the overnight broth. The average number of PER/109 viable bacteria after overnight growth in broths inoculated from a frozen permanent, lyophilized permanent, master plate, and an isolated colony, of TA98 were 267, 188, 57 and 13 respectively. The resultant elevation of the number of SR for a strain may result in a failure to identify a mutagenic response. It is recommended that the number of PER be monitored in any modification of the Ames test that makes use of elevated numbers of bacteria.
Supramolecular Chemistry, 2015
Org. Biomol. Chem., 2015
Three organic ionophores (2-4) based on the p-tert-butylthiacalix[4]arene backbone, blocked in th... more Three organic ionophores (2-4) based on the p-tert-butylthiacalix[4]arene backbone, blocked in the 1,3alternate conformation, bearing two pyridyl coordinating moieties (ortho for 2, meta for 3 and para for 4), have been synthesized and characterized in the solid state. The solvent extraction experiments with the metal ions showed that the ability of these derivatives to complex with Ag + appeared to be largely dependent on the position of the nitrogen atoms of the pyridyl ring. Two different complexation modes have been confirmed by 1 H NMR titration. Ionophore 2 armed with two pyridyl moieties, complexed with Ag + cation through N⋯Ag + ⋯S interactions; however, ionophore 3 and ionophore 4 complexed with Ag + through metal-nitrogen (N⋯Ag + ) interactions. The DFT computational studies were consistent with the experimental findings. These findings will provide us with an important rule to design an appropriate thiacalix[4]arene ionophore in the future. Another study on the possibility for application of ionophores 2-4 for the treatment of waste water containing Cr(VI) and Cr(III), showed that ionophore 3 was useful in the application of the solvent extraction method in selective treatment of waste water containing Cr(VI) and Cr(III) prior to discharge. † Electronic supplementary information (ESI) available: Details of single-crystal X-ray crystallographic data. 1 H, 13 C NMR, MS and IR spectra of 3, computational study of 2-4 with Ag + . CCDC 1021161. For ESI and crystallographic data in CIF or other electronic format see
Studies in Natural Products Chemistry, 2012
Tetrahedron Letters, 2010
The enantioselective synthesis of each of the enantiomers of N-norlaudanidine, a minor Papaver so... more The enantioselective synthesis of each of the enantiomers of N-norlaudanidine, a minor Papaver somniferum opium benzyltetrahydoisoquinoline alkaloid is described. This was achieved using a chiral auxiliarymediated Bischler-Napieralski cyclization-sodium borohydride reduction strategy. The X-ray crystal structures of each of these secondary amines are reported.
New J. Chem., 2014
A ''bimodal'' or upper-and lower-rim functionalized ''calix-crown-5'' reported herein was unexpec... more A ''bimodal'' or upper-and lower-rim functionalized ''calix-crown-5'' reported herein was unexpectedly formed preferentially in a cone conformation. This was confirmed both by NMR spectroscopy and by single-crystal X-ray crystallography. The thioacetate functionalities on the new calix-crown-5 enabled it to form stable SAMs on the Au surface of a microcantilever, and a sensitive cesium ion sensor. Fig. 1 Structures of cone-1 and 1,3-alternate-2.
Sensors and Actuators B: Chemical, 2014
The use of a bimodal calix[4]arene 2, was investigated as a potential host/guest sensing layer fo... more The use of a bimodal calix[4]arene 2, was investigated as a potential host/guest sensing layer for microcantilever sensors for detecting selected ions in dilute aqueous solutions. It was found that the sensing layers gave the highest microcantilever sensitivity when microcantilevers coated with 5 nm of Inconel and 40 nm of Au were incubated for 1 h in a 1.0 M dichloromethane:ethanol (1:9) solution of calix[4]arene 2. This calix[4]arene 2 was observed to form well-ordered self-assembled monolayers (SAM) on Au-coated substrates with no sign of bare areas or etch pits. Microcantilever sensor measurements showed that the calix[4]arene 2-functionalized cantilevers were able to detect Ca 2+ ions in aqueous solutions of CaCl 2 at concentrations as low as 10 −12 M. Although this receptor was shown to have a high affinity for CaCl 2 in aqueous solutions, it was also found to be able to detect other ionic compounds, however only producing microcantilever deflections ranging from 10% to 30% of those obtained for CaCl 2 .