Emilios Patsalides - Academia.edu (original) (raw)

Papers by Emilios Patsalides

Research paper thumbnail of Gas chromatography of metal �-diketonates and their analogues

Research paper thumbnail of Retention of fluorinated transition-metal �-diketonates in gas chromatographic columns

Research paper thumbnail of Kerr constants and dielectric polarisations of amides and thioamides in water and dioxane solutions

Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 1988

Measurements of dielectric polarisations and electric birefringences are reported for simple amid... more Measurements of dielectric polarisations and electric birefringences are reported for simple amides and thioamides in dilute aqueous and dioxane solutions. Interpretation of the exerimental data is made according to the Onsager, Block–Walker modified Onsager, and Lorentz models for the internal static field. The derived solute polarisability anisotropies from water are in fair concordance with those from dioxane provided the Onsager model is used. Combining refractivity and optical anisotropy data, polarisability tensor elements are derived for the solutes in water which are reasonably close to those in dioxane.

Research paper thumbnail of Hexamethylmelamine: a study of solvation and crystallisation

Journal of the Chemical Society, Perkin Transactions 2, 1987

Dielectric, electro-optic, and spectroscopic properties of hexamethylmelamine (HMM) are examined ... more Dielectric, electro-optic, and spectroscopic properties of hexamethylmelamine (HMM) are examined in various solvents. The study is an extension of earlier work relating the dielectric characteristics of solvent to the habit of HMM crystals, a factor of importance to the effectiveness of pulmonary administration of this drug in the treatment of human small-call lung carcinoma. In solution HMM is confirmed to be non-dipolar though abnormally large atomic polarisation is found. The optical polarisability anisotropy correlates with an extensively delocalised π-system involving the triazine ring and the exocyclic nitrogens. Interactions between HMM and cyclohexane, dioxane, and benzene are weak and not sterically defined—each of these solvents yields predominantly ‘compact’ crystal forms of HMM. In hexafluorobenzene definitive evidence is provided for strongly favoured stereospecific face-to-face HMM–C6F6 interactions. Needle-shaped crystals obtained from this solvent very rapidly become opaque and friable. Thermal analysis indicates an unstable 1 : 1 HMM–C6F6 adduct. This was confirmed by X-ray crystal structure determination which showed that HMM and C6F6 alternate in infinite columns, suggestive of a π–π interaction between the rings. The study provides an important correlation, based on experiment, between the statistically preferred HMM–C6F6 configuration in solution and that found for the crystalline adduct when isolated.

Research paper thumbnail of Dehydrogenation at the ethane bridge in transition metal chelates of tetradentate Schiff bases

Journal of the Chemical Society, Chemical Communications, 1979

Research paper thumbnail of Advances in the analytical chromatography of the lanthanides. A review

Research paper thumbnail of Rancidity and its measurement in edible oils and snack foods. A review

The Analyst, 1988

1: Analyst. 1988 Feb;113(2):213-24. Rancidity and its measurement in edible oils and snack foods.... more 1: Analyst. 1988 Feb;113(2):213-24. Rancidity and its measurement in edible oils and snack foods. A review. Robards K, Kerr AF, Patsalides E. ...

Research paper thumbnail of Metal determination and metal speciation by liquid chromatography. A review

The Analyst, 1991

... Chem., 1981, 53, 2309 Article ChemPort . 52, S. Sheikh, A. Pathan and N. Naqvi, J. Chem. Soc.... more ... Chem., 1981, 53, 2309 Article ChemPort . 52, S. Sheikh, A. Pathan and N. Naqvi, J. Chem. Soc. Pak., 1985, 7, 333 . 53, E. Basova, T. Bol'shova and T. Shirshova, Vestn Mosk. Univ., 1988, 29, 598 ; E. Basova, T. Bol'shova and T. Shirshova, Chem. Abstr., 1989, 111, 186385t . ...

Research paper thumbnail of Methods for testing antioxidant activity

Research paper thumbnail of Stability and the gas chromatography of alkyl-substituted η6-benzenetricarbonylchromium(O) complexes

Journal of Organometallic Chemistry, 1989

Abstract Thermoanalytical and gas chromatographic data are reported for benzenetricarbonylchromiu... more Abstract Thermoanalytical and gas chromatographic data are reported for benzenetricarbonylchromium(0) and nine of its methyl- and t-butyl-substituted derivatives. The distinct trends found for the volatilities, thermal stabilities, air stabilities and gas chromatographic retentions with increasing alkyl substitution are interpreted in terms of Cr ligand bond energies and polarity and steric effects. Satisfactory chromatographic behaviour was observed only when highly inert columns were used, and when the solutions were deaerated and stored in the dark.

Research paper thumbnail of Rapid chromatographic determination of benzotriazoles in automotive cooling waters and cooling water formulations

Journal of Chromatography A, 1985

The chromatographic behaviour of benzotriazole and several of its derivatives on gas chromatograp... more The chromatographic behaviour of benzotriazole and several of its derivatives on gas chromatographic (GC) fused-silica wall-coated open-tubular columns and reversed-phase liquid chromatographic (LC) columns is reported. Although severe tailing and irreversible retention were observed on polar GC columns, considerably improved behaviour was obtained on non-polar OV-101 and moderate polarity BP-10 columns, with detection limits (flame ionization detection) being in the nanogram range. Of the reversed-phase LC columns examined, Spherisorb 5 C8 was the most suitable, producing little or no tailing. Detection limits on this column with UV detection at 254 nm were also in the nanogram range. An LC method for determining benzotriazoles in both automotive cooling waters and cooling water formulations involving only dilution of the sample prior to analysis, is described.

Research paper thumbnail of Chromatographic separation of isomeric forms of a tetradentate schiff base derived from 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dione and 1,2-diaminoethane

Journal of Chromatography A, 1977

Abstract Reaction between the asymmetrical β-diketone 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dion... more Abstract Reaction between the asymmetrical β-diketone 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dione with 1,2-diaminoethane gives, among other products, two distinct tetradentate ketoenamine isomers. These compounds have been separated chromatographically from the numerous reaction products and identified. The major product of the reaction was the dihydrodiazepin derivative. Some properties of the isomers are given.

Research paper thumbnail of Retention of fluorinated transition-metal β-diketonates in gas chromatographic columns

Journal of Chromatography A, 1979

Abstract Retention of the Al(III), V(III), Cr(III), Fe(III), Mn(III), Co(III) and Cu(II) derivati... more Abstract Retention of the Al(III), V(III), Cr(III), Fe(III), Mn(III), Co(III) and Cu(II) derivatives of the β-diketones, 1,1,1-trifluoropentane-2,4-dione, 1,1,1,5,5,5-hexafluoropentane-2,4-dione, 1,1,1-trifluoro-5-methylhexane-2,4-dione, 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dione, 1,1,1,3,3-pentafluoro-6,6-dimethylheptane-3,5-dione and 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dione in chromatographic columns with various supports has been studied. Chemical effects due to the nature of the support, ligand and the metal ion probably contribute to the observed magnitude of the retention. Irreversability of the phenomenon is interpreted as arising from dissociation in the stationary phase and retention therein or to reaction at active sites on the support. Several mechanisms for these reactions are proposed.

Research paper thumbnail of Applications of fused-silica wall-coated open-tubular columns

Journal of Chromatography A, 1986

Abstract The gas chromatography on fused-silica capillary columns are reported for seventeen tran... more Abstract The gas chromatography on fused-silica capillary columns are reported for seventeen transition metal complexes on non-fluorinated Schiff base ligands, including aminothione ligands. Data presented include chromatograms showing various group separations, column activity effects, detection limits, specific retention volumes, rate constants for the chelate decompositions and enthalpies for the solution processes in the bonded stationary phases. The fused-silica columns were found to be generally superior to packed columns, particularly with regard to peak symmetry and resolution. However, activity effects were still evident, with distinct contributions from reversible adsorption, irreversible adsorption and catalysis being observed. The reactive nature of some of the chelates, notably the aminothione chelates and palladium and platinum chelates, seems to preclude their utilization for analytical purposes.

Research paper thumbnail of Chromatographic and other properties of novel tetradentate tetraketo schiff base and chelates

Journal of Chromatography A, 1986

Abstract The synthesis and characterisation of a new class of tetradentate Schiff bases obtained ... more Abstract The synthesis and characterisation of a new class of tetradentate Schiff bases obtained from the condensation of oxalyl chloride and the bidentate Schiff base 4- aminopent-3-en-2-one and its analogues are reported, together with their copper(II) and nickel(II) complexes. Data are presented from studies including gas chromatography, spectroscopy (infrared, mass and 1 H NMR), thermal analysis, cyclic voltammetry and measurements of dipole moments. In the chelates, the 1,2-dicarbonyl group at the bridge lowers their thermal stability, reverses the direction of the dipole moment with little change in magnitude, and gives rise to reversible electrochemical oxidation and reduction. Differences between chelates and the corresponding ligands are discussed in terms of electron delocalisation in the dicarbonyl bridge. Chromatographic and spectroscopic evidence supports the existence of structural isomers in the unsymmetrical tetraketo compounds, and, hence, in the original bidentate Schiff bases used in their synthesis.

Research paper thumbnail of Comparison of the liquid and gas chromatography of five classes of metal complexes

Journal of Chromatography A, 1999

... School of Science and Technology, Charles Sturt University, PO Box 588, Wagga Wagga 2650, Aus... more ... School of Science and Technology, Charles Sturt University, PO Box 588, Wagga Wagga 2650, Australia. Received 21 December 1998; revised 9 March 1999; Accepted 12 March 1999. Available online 7 June 1999. Abstract. ...

Research paper thumbnail of Gas chromatography of metal β-diketonates and their analogues

Journal of Chromatography A, 1987

Research paper thumbnail of Gas chromatography of iron (III) chelates of hexadentate schiff bases

Journal of Chromatography A, 1983

Attempts to determine iron by gas chromatography (CC) of volatile a-diketonate derivativeslP6 hav... more Attempts to determine iron by gas chromatography (CC) of volatile a-diketonate derivativeslP6 have so far been largely unsuccessful due to the instability and reactivity of the chelates. Although iron I-diketonates appear stable during volatilisation, very poor chromatographic peaks are usually produced, even at microgram levels, because of adsorptive loading, peak broadening, elevated baselines and displacement, and memory effects4*6,7. At nanogram levels, such chelates are irreversibly retained on the column for reasons attributed6 to dissociation in the stationary phase and adsorption at active sites on the support. These limitations have, to some extent, been overcome by addition of free ligand to the carrier gas+'O, presumably to maintain equilibrium in favour of the undissociated chelate. Another investigation has abandoned chelate derivatives and examined an indirect method for determining iron by GC". An alternative approach for improving the GC of iron chelates6 involves forming chelates with higher dissociative stability than that of the /3-diketonates. This can be accomplished by using multidentate ligands to maximize stability through the "chelate effect". In this paper we examine the hexadentate Schiff bases 4,4',4"-(neopentane-l,3,4-triyltriimino)tris(pent-3-en-2-one) (I), and 4,4',4"-(cyclohexanecis,cis-1,3,5-triyltriimino)tris(pent-3-en-2-one) (IT), for this purpose and report on the formation, stability and GC of the iron(TI1) chelates (III and IV).

Research paper thumbnail of Gas chromatography of transition metal derivatives of the sulphur analogues of 4,4′-(ethane-1,2-diyldiimino)bis-(pent-3-en-2-one)

Journal of Chromatography A, 1979

Research paper thumbnail of Volatile benzotriazole derivatives of the nitrite ion

Journal of Chromatography A, 1983

Research paper thumbnail of Gas chromatography of metal �-diketonates and their analogues

Research paper thumbnail of Retention of fluorinated transition-metal �-diketonates in gas chromatographic columns

Research paper thumbnail of Kerr constants and dielectric polarisations of amides and thioamides in water and dioxane solutions

Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 1988

Measurements of dielectric polarisations and electric birefringences are reported for simple amid... more Measurements of dielectric polarisations and electric birefringences are reported for simple amides and thioamides in dilute aqueous and dioxane solutions. Interpretation of the exerimental data is made according to the Onsager, Block–Walker modified Onsager, and Lorentz models for the internal static field. The derived solute polarisability anisotropies from water are in fair concordance with those from dioxane provided the Onsager model is used. Combining refractivity and optical anisotropy data, polarisability tensor elements are derived for the solutes in water which are reasonably close to those in dioxane.

Research paper thumbnail of Hexamethylmelamine: a study of solvation and crystallisation

Journal of the Chemical Society, Perkin Transactions 2, 1987

Dielectric, electro-optic, and spectroscopic properties of hexamethylmelamine (HMM) are examined ... more Dielectric, electro-optic, and spectroscopic properties of hexamethylmelamine (HMM) are examined in various solvents. The study is an extension of earlier work relating the dielectric characteristics of solvent to the habit of HMM crystals, a factor of importance to the effectiveness of pulmonary administration of this drug in the treatment of human small-call lung carcinoma. In solution HMM is confirmed to be non-dipolar though abnormally large atomic polarisation is found. The optical polarisability anisotropy correlates with an extensively delocalised π-system involving the triazine ring and the exocyclic nitrogens. Interactions between HMM and cyclohexane, dioxane, and benzene are weak and not sterically defined—each of these solvents yields predominantly ‘compact’ crystal forms of HMM. In hexafluorobenzene definitive evidence is provided for strongly favoured stereospecific face-to-face HMM–C6F6 interactions. Needle-shaped crystals obtained from this solvent very rapidly become opaque and friable. Thermal analysis indicates an unstable 1 : 1 HMM–C6F6 adduct. This was confirmed by X-ray crystal structure determination which showed that HMM and C6F6 alternate in infinite columns, suggestive of a π–π interaction between the rings. The study provides an important correlation, based on experiment, between the statistically preferred HMM–C6F6 configuration in solution and that found for the crystalline adduct when isolated.

Research paper thumbnail of Dehydrogenation at the ethane bridge in transition metal chelates of tetradentate Schiff bases

Journal of the Chemical Society, Chemical Communications, 1979

Research paper thumbnail of Advances in the analytical chromatography of the lanthanides. A review

Research paper thumbnail of Rancidity and its measurement in edible oils and snack foods. A review

The Analyst, 1988

1: Analyst. 1988 Feb;113(2):213-24. Rancidity and its measurement in edible oils and snack foods.... more 1: Analyst. 1988 Feb;113(2):213-24. Rancidity and its measurement in edible oils and snack foods. A review. Robards K, Kerr AF, Patsalides E. ...

Research paper thumbnail of Metal determination and metal speciation by liquid chromatography. A review

The Analyst, 1991

... Chem., 1981, 53, 2309 Article ChemPort . 52, S. Sheikh, A. Pathan and N. Naqvi, J. Chem. Soc.... more ... Chem., 1981, 53, 2309 Article ChemPort . 52, S. Sheikh, A. Pathan and N. Naqvi, J. Chem. Soc. Pak., 1985, 7, 333 . 53, E. Basova, T. Bol'shova and T. Shirshova, Vestn Mosk. Univ., 1988, 29, 598 ; E. Basova, T. Bol'shova and T. Shirshova, Chem. Abstr., 1989, 111, 186385t . ...

Research paper thumbnail of Methods for testing antioxidant activity

Research paper thumbnail of Stability and the gas chromatography of alkyl-substituted η6-benzenetricarbonylchromium(O) complexes

Journal of Organometallic Chemistry, 1989

Abstract Thermoanalytical and gas chromatographic data are reported for benzenetricarbonylchromiu... more Abstract Thermoanalytical and gas chromatographic data are reported for benzenetricarbonylchromium(0) and nine of its methyl- and t-butyl-substituted derivatives. The distinct trends found for the volatilities, thermal stabilities, air stabilities and gas chromatographic retentions with increasing alkyl substitution are interpreted in terms of Cr ligand bond energies and polarity and steric effects. Satisfactory chromatographic behaviour was observed only when highly inert columns were used, and when the solutions were deaerated and stored in the dark.

Research paper thumbnail of Rapid chromatographic determination of benzotriazoles in automotive cooling waters and cooling water formulations

Journal of Chromatography A, 1985

The chromatographic behaviour of benzotriazole and several of its derivatives on gas chromatograp... more The chromatographic behaviour of benzotriazole and several of its derivatives on gas chromatographic (GC) fused-silica wall-coated open-tubular columns and reversed-phase liquid chromatographic (LC) columns is reported. Although severe tailing and irreversible retention were observed on polar GC columns, considerably improved behaviour was obtained on non-polar OV-101 and moderate polarity BP-10 columns, with detection limits (flame ionization detection) being in the nanogram range. Of the reversed-phase LC columns examined, Spherisorb 5 C8 was the most suitable, producing little or no tailing. Detection limits on this column with UV detection at 254 nm were also in the nanogram range. An LC method for determining benzotriazoles in both automotive cooling waters and cooling water formulations involving only dilution of the sample prior to analysis, is described.

Research paper thumbnail of Chromatographic separation of isomeric forms of a tetradentate schiff base derived from 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dione and 1,2-diaminoethane

Journal of Chromatography A, 1977

Abstract Reaction between the asymmetrical β-diketone 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dion... more Abstract Reaction between the asymmetrical β-diketone 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dione with 1,2-diaminoethane gives, among other products, two distinct tetradentate ketoenamine isomers. These compounds have been separated chromatographically from the numerous reaction products and identified. The major product of the reaction was the dihydrodiazepin derivative. Some properties of the isomers are given.

Research paper thumbnail of Retention of fluorinated transition-metal β-diketonates in gas chromatographic columns

Journal of Chromatography A, 1979

Abstract Retention of the Al(III), V(III), Cr(III), Fe(III), Mn(III), Co(III) and Cu(II) derivati... more Abstract Retention of the Al(III), V(III), Cr(III), Fe(III), Mn(III), Co(III) and Cu(II) derivatives of the β-diketones, 1,1,1-trifluoropentane-2,4-dione, 1,1,1,5,5,5-hexafluoropentane-2,4-dione, 1,1,1-trifluoro-5-methylhexane-2,4-dione, 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dione, 1,1,1,3,3-pentafluoro-6,6-dimethylheptane-3,5-dione and 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dione in chromatographic columns with various supports has been studied. Chemical effects due to the nature of the support, ligand and the metal ion probably contribute to the observed magnitude of the retention. Irreversability of the phenomenon is interpreted as arising from dissociation in the stationary phase and retention therein or to reaction at active sites on the support. Several mechanisms for these reactions are proposed.

Research paper thumbnail of Applications of fused-silica wall-coated open-tubular columns

Journal of Chromatography A, 1986

Abstract The gas chromatography on fused-silica capillary columns are reported for seventeen tran... more Abstract The gas chromatography on fused-silica capillary columns are reported for seventeen transition metal complexes on non-fluorinated Schiff base ligands, including aminothione ligands. Data presented include chromatograms showing various group separations, column activity effects, detection limits, specific retention volumes, rate constants for the chelate decompositions and enthalpies for the solution processes in the bonded stationary phases. The fused-silica columns were found to be generally superior to packed columns, particularly with regard to peak symmetry and resolution. However, activity effects were still evident, with distinct contributions from reversible adsorption, irreversible adsorption and catalysis being observed. The reactive nature of some of the chelates, notably the aminothione chelates and palladium and platinum chelates, seems to preclude their utilization for analytical purposes.

Research paper thumbnail of Chromatographic and other properties of novel tetradentate tetraketo schiff base and chelates

Journal of Chromatography A, 1986

Abstract The synthesis and characterisation of a new class of tetradentate Schiff bases obtained ... more Abstract The synthesis and characterisation of a new class of tetradentate Schiff bases obtained from the condensation of oxalyl chloride and the bidentate Schiff base 4- aminopent-3-en-2-one and its analogues are reported, together with their copper(II) and nickel(II) complexes. Data are presented from studies including gas chromatography, spectroscopy (infrared, mass and 1 H NMR), thermal analysis, cyclic voltammetry and measurements of dipole moments. In the chelates, the 1,2-dicarbonyl group at the bridge lowers their thermal stability, reverses the direction of the dipole moment with little change in magnitude, and gives rise to reversible electrochemical oxidation and reduction. Differences between chelates and the corresponding ligands are discussed in terms of electron delocalisation in the dicarbonyl bridge. Chromatographic and spectroscopic evidence supports the existence of structural isomers in the unsymmetrical tetraketo compounds, and, hence, in the original bidentate Schiff bases used in their synthesis.

Research paper thumbnail of Comparison of the liquid and gas chromatography of five classes of metal complexes

Journal of Chromatography A, 1999

... School of Science and Technology, Charles Sturt University, PO Box 588, Wagga Wagga 2650, Aus... more ... School of Science and Technology, Charles Sturt University, PO Box 588, Wagga Wagga 2650, Australia. Received 21 December 1998; revised 9 March 1999; Accepted 12 March 1999. Available online 7 June 1999. Abstract. ...

Research paper thumbnail of Gas chromatography of metal β-diketonates and their analogues

Journal of Chromatography A, 1987

Research paper thumbnail of Gas chromatography of iron (III) chelates of hexadentate schiff bases

Journal of Chromatography A, 1983

Attempts to determine iron by gas chromatography (CC) of volatile a-diketonate derivativeslP6 hav... more Attempts to determine iron by gas chromatography (CC) of volatile a-diketonate derivativeslP6 have so far been largely unsuccessful due to the instability and reactivity of the chelates. Although iron I-diketonates appear stable during volatilisation, very poor chromatographic peaks are usually produced, even at microgram levels, because of adsorptive loading, peak broadening, elevated baselines and displacement, and memory effects4*6,7. At nanogram levels, such chelates are irreversibly retained on the column for reasons attributed6 to dissociation in the stationary phase and adsorption at active sites on the support. These limitations have, to some extent, been overcome by addition of free ligand to the carrier gas+'O, presumably to maintain equilibrium in favour of the undissociated chelate. Another investigation has abandoned chelate derivatives and examined an indirect method for determining iron by GC". An alternative approach for improving the GC of iron chelates6 involves forming chelates with higher dissociative stability than that of the /3-diketonates. This can be accomplished by using multidentate ligands to maximize stability through the "chelate effect". In this paper we examine the hexadentate Schiff bases 4,4',4"-(neopentane-l,3,4-triyltriimino)tris(pent-3-en-2-one) (I), and 4,4',4"-(cyclohexanecis,cis-1,3,5-triyltriimino)tris(pent-3-en-2-one) (IT), for this purpose and report on the formation, stability and GC of the iron(TI1) chelates (III and IV).

Research paper thumbnail of Gas chromatography of transition metal derivatives of the sulphur analogues of 4,4′-(ethane-1,2-diyldiimino)bis-(pent-3-en-2-one)

Journal of Chromatography A, 1979

Research paper thumbnail of Volatile benzotriazole derivatives of the nitrite ion

Journal of Chromatography A, 1983