Reijo Aksela - Academia.edu (original) (raw)
Papers by Reijo Aksela
Polymer, Dec 1, 2005
We have studied metal ion complexation with poly(carboxylic acid) ligands using density functiona... more We have studied metal ion complexation with poly(carboxylic acid) ligands using density functional methods and a continuum solvation model (COSMO). Geometry optimisations have been carried out for metal complexes of poly(acrylic acid) (PAA) and poly(a-hydroxy acrylic acid) (PHA) oligomers. The complexation energies for Mg 2C , Ca 2C , Mn 2C , Fe 3C , and Zn 2C with one oligomer ligand (pentamer), and two ligands (dimer and trimer) have been calculated. The nature of hydrogen bonding in PHA has been studied both in free oligomers and in metal complexes. The obtained binding degrees are in good agreement with experimental results although with quite small energy differences. The complexation energies were found to be very sensitive to changes in internal hydrogen bonds. The role of hydroxyl oxygen atoms in metal ion binding was observed to be more important for Ca 2C than for other metals.
Journal of Coordination Chemistry, Jun 20, 2010
In a search for environmental-friendly metal chelating ligands for industrial applications, the p... more In a search for environmental-friendly metal chelating ligands for industrial applications, the protonation and complex formation equilibria of 3-hydroxy-2,2′-iminodisuccinic acid with Mg, Ca, Mn, Fe, Fe, Co, Ni, Cu, and Zn ions in aqueous 0.1 mol L NaCl solution were studied at 25°C by potentiometric titration. The model for complexation and the stability constants of the different complexes were determined
Canadian Journal of Chemistry, Jul 1, 1986
Syntheses of 11- and 12-hydroxy-(Z)-3-dodecenic, 11- and 12-hydroxy-(Z,Z)-3,6-dodecadienic, and 1... more Syntheses of 11- and 12-hydroxy-(Z)-3-dodecenic, 11- and 12-hydroxy-(Z,Z)-3,6-dodecadienic, and 13-hydroxy-(Z,Z)-5,8-tetradecadienic acids are reported. These unsaturated hydroxy acids are precursors of male-produced macrolide aggregation pheromones of grain beetles of the genera Cryptolestes and Oryzaephilus. The sequence of reactions for synthesis of the hydroxy-(Z)-3 acids was carboxylation of the dilithium salt of 10- or 11-hydroxy undecyne, deconjugation of the resulting carboxylic acids with NaNH2 in THF/liquid ammonia to a mixture of 2,3-allenic and 3-alkynoic acids, and hydrogenation of the mixture with P-2 nickel catalyst. This latter reaction gave only the desired hydroxy-(Z)-3-alkenoic acids. The convergent point in the syntheses of the diunsaturated hydroxy-(Z,Z) acids was the coupling of the dimagnesium salt of 3-butyn-1-ol or 5-hexyn-1-ol to the appropriate functionalized propargylic bromide. The resulting 1,4-diacetylenic alcohols were oxidized with Jones reagent to the corresponding carboxylic acids, which were hydrogenated over P-2 nickel catalyst and deprotected.
ChemInform, Aug 23, 2010
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more 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 Coordination Chemistry, Mar 20, 2008
The persistence of widely used chelating agents EDTA and DTPA in nature has been of concern and t... more The persistence of widely used chelating agents EDTA and DTPA in nature has been of concern and there is a need for ligands to replace them. In a search for environmentally friendly metal chelating ligands for industrial applications, complex formation equilibria of N-bis[2-(1,2-dicarboxyethoxy)ethyl]aspartic acid (BCA6) with Cd(II), Hg(II) and Pb(II) in aqueous 0.1 M NaNO3 solution were studied at 25°C
Journal of Coordination Chemistry, Dec 20, 2009
In a search for environment-friendly metal chelating ligands for industrial applications, the pro... more In a search for environment-friendly metal chelating ligands for industrial applications, the protonation and complex formation equilibria of N-bis[2-(1,2-dicarboxyethoxy)ethyl]aspartic acid (BCA6) with Fe(II), Co(II), and Ni(II) ions in aqueous 0.1 M NaCl solution were studied at 25°C by potentiometric titration. The model for complexation and the stability constants of different complexes were determined for each metal ion using SUPERQUAD. In all cases, complex formation was dominated by stable ML complexes.
Appita Journal, Mar 1, 2006
In a search for environmentally friendly metal chelating ligands the protonation and complex form... more In a search for environmentally friendly metal chelating ligands the protonation and complex formation equilibria of N-bis [2-(1,2-dicarboxyethoxy)ethyl] aspartic acid, N-bis[2-(1,2-dicarboxyethoxy)ethyl]-glycine and N-bis[2-(1,2-dicarboxyethoxy)ethyl]-methylglycine with Mg(II), Ca(II), Mn(II), Fe(III), Cu(II), and Zn(II) in aqueous 0.1 M NaCl solution were studied at 25 C by potentiometric titration. The model of the complexation and the stability constants of the different complexes were determined for each metal ion using the computer program SUPERQUAD. With all metals the complex formation was dominated by stable MLn-6 or MLn-5 complexes. The performance of these new complexing agents was studied in a TCF bleaching of eucalyptus pulp (E. Globulus) via a sequence O-Q-P1-PAA-P2.
Journal of Coordination Chemistry, Aug 10, 2012
ABSTRACT In search for environmentally friendly metal chelating ligands for industrial applicatio... more ABSTRACT In search for environmentally friendly metal chelating ligands for industrial applications, protonation and complex-formation equilibria of iminodisuccinic acid (IDS), 3-hydroxy-2,2’-iminodisuccinic acid (HIDS), N,N’-ethylenediaminedisuccinic acid (EDDS), and oxydisuccinic acid (ODS) with La in aqueous 0.1 mol L NaCl solution were studied at 25 °C by potentiometric titration. The model for complexation and the stability constants of the different complexes were determined using the computer program SUPERQUAD. Complex formation was dominated by stable LaL complexes for all tested ligands.
Holzforschung, Sep 1, 2005
The decomposition mechanism of peracetic acid by free Mn 2q ions and by Mn 2q-diethylenetriaminep... more The decomposition mechanism of peracetic acid by free Mn 2q ions and by Mn 2q-diethylenetriaminepentaacetic acid complexes was studied by UV/Vis, electrospray ionization-time of flight-mass spectrometry (ESI-TOF-MS), electron spin resonance (ESR), and Raman spectroscopy. The experimental results demonstrate that a number of different oxidation states of manganese are involved in the decomposition reaction. Furthermore, the kinetics observed show oscillatory features that are characteristic of autocatalytic processes. Radical pathways were found to play a negligible role in the reaction. Based on the experimental observations, an overall reaction scheme for the decomposition process is proposed.
Journal of the Chemical Society, 2002
ABSTRACT The protonation and complex formation equilibria of N,N′-ethylenediaminedisuccinic acid ... more ABSTRACT The protonation and complex formation equilibria of N,N′-ethylenediaminedisuccinic acid (EDDS) in the isomeric form [S,S] and a mixture of EDDS isomers (25% [S,S], 50% [R,S], 25% [R,R]) with Fe(III), Cu(II), Zn(II) and Mn(II) have been studied in aqueous 0.1 M NaCl solution at 25 °C by potentiometric titrations. The calculations were carried out with the computer program SUPERQUAD.
Holzforschung, Aug 1, 2007
Stabilization of aqueous H 2 O 2 solutions containing small amounts of transition metal impuritie... more Stabilization of aqueous H 2 O 2 solutions containing small amounts of transition metal impurities we.g., Mn(II) and Fe(II)x was studied in terms of UV/Vis and electron spin resonance spectroscopy and oxygen concentration measurements at pH ;11. The results show that aspartic acid diethoxy succinate (AES) could stabilize H 2 O 2 solutions when Mn(II) and Fe(II) were present. Diethylenetriamine pentaacetic acid (DTPA) showed similar behavior, but was not able to stabilize the solutions as efficiently as AES. In the long-term regime, Na-poly-alpha-hydroxyacrylate was almost as effective a stabilizing agent as AES. Na-acrylate-3-allyloxide-2-hydroxy propane Nasulfonate copolymer (Aqualic) could decrease H 2 O 2 decomposition by one order of magnitude, but it was the least efficient stabilizing agent among the substances studied. Furthermore, generation of superoxide radical was not suppressed in the presence of Aqualic.
Journal of Coordination Chemistry, Mar 10, 2011
... Helena Hyvönen a * , Laura Svärd a & Reijo Aksela b pages 1091-1103. ... Hyvönen, H, Oram... more ... Helena Hyvönen a * , Laura Svärd a & Reijo Aksela b pages 1091-1103. ... Hyvönen, H, Orama, M, Saarinen, H and Aksela, R. 2003. Green Chem. , 5: 410 [CrossRef], [Web of Science ®] View all references and HIDS 1616. Hyvönen, H and Aksela, R. 2010. J. Coord. Chem. ...
Tetrahedron Letters, 1990
Solutions comprised of equlmolar concentrations of methyllithium, trimethylstannylllthium and cup... more Solutions comprised of equlmolar concentrations of methyllithium, trimethylstannylllthium and cuprous cyanide as well as reaction of MezCu(CN)Lia with one equivalent of hexamethylditin give MegSn(Me)Cu(CN)Li2 which selectively delivers the R6Sn moiety to a variety of substrates.
Holzforschung, Aug 1, 2007
Stabilization of peracetic acid (PAA) by aspartic acid diethoxy succinate (AES) was studied by el... more Stabilization of peracetic acid (PAA) by aspartic acid diethoxy succinate (AES) was studied by electron spin resonance, UV/Vis spectroscopy, electrospray ionization time-of-flight mass spectrometry and oxygen evolution measurements. The results indicate that Mn(II)-AES complexes may exist in both monomeric and dimeric forms. Dimerization is proposed to proceed via formation of an oxygen bridge between two Mn(II)-AES complexes. The equilibrium between these two forms depends strongly on pH, the monomeric form being favored under acidic conditions, while conditions close to neutral pH favor the dimeric form. In the presence of PAA, the dimer form was oxidized and finally yielded MnO 2. Oxygen evolution measurements were carried out to demonstrate the efficiency of AES in stabilizing PAA solutions containing small amounts of Mn(II) impurities under acidic conditions.
Japan Tappi Journal, 1998
Journal of Coordination Chemistry, Aug 20, 2008
In a search for environmentally friendly metal chelating ligands for industrial applications, the... more In a search for environmentally friendly metal chelating ligands for industrial applications, the protonation and complex formation equilibria of [S,S,S]- and [R,S,R]-isomers of N-bis[2-(1,2-dicarboxyethoxy)ethyl] aspartic acid (BCA6) with Mg(II), Ca(II), Mn(II), Fe(III), Cu(II) and Zn(II) ions in aqueous 0.1 M NaCl solution were studied at 25°C by potentiometric titration. The model for complexation and the stability constants of the different
Journal of Coordination Chemistry, May 11, 2007
In a search for environmentally friendly metal chelating ligands the complex formation equilibria... more In a search for environmentally friendly metal chelating ligands the complex formation equilibria of N-bis[2-(1,2-dicarboxyethoxy)ethyl] glycine (BCA5), N-bis[2-(1,2-dicarboxyethoxy)ethyl] aspartic acid (BCA6), and N-tris[(1,2-dicarboxyethoxy)ethyl] amine (TCA6) with La(III) in aqueous 0.1 M NaCl solution were studied at 25°C by potentiometric titration. The models of the complexation and stability constants of the different complexes were determined using the computer program SUPERQUAD. With TCA6
Journal of Coordination Chemistry, Sep 10, 2005
... The value of the liquid junction coefficient, j OH , valid in basic solutions, was determined... more ... The value of the liquid junction coefficient, j OH , valid in basic solutions, was determined periodically. ... In the micromolar concentration area, dilution of the solution increases the lower pH limit of the effective chelation region to more basic values. View larger version(30K). ...
Polymer, Dec 1, 2005
We have studied metal ion complexation with poly(carboxylic acid) ligands using density functiona... more We have studied metal ion complexation with poly(carboxylic acid) ligands using density functional methods and a continuum solvation model (COSMO). Geometry optimisations have been carried out for metal complexes of poly(acrylic acid) (PAA) and poly(a-hydroxy acrylic acid) (PHA) oligomers. The complexation energies for Mg 2C , Ca 2C , Mn 2C , Fe 3C , and Zn 2C with one oligomer ligand (pentamer), and two ligands (dimer and trimer) have been calculated. The nature of hydrogen bonding in PHA has been studied both in free oligomers and in metal complexes. The obtained binding degrees are in good agreement with experimental results although with quite small energy differences. The complexation energies were found to be very sensitive to changes in internal hydrogen bonds. The role of hydroxyl oxygen atoms in metal ion binding was observed to be more important for Ca 2C than for other metals.
Journal of Coordination Chemistry, Jun 20, 2010
In a search for environmental-friendly metal chelating ligands for industrial applications, the p... more In a search for environmental-friendly metal chelating ligands for industrial applications, the protonation and complex formation equilibria of 3-hydroxy-2,2′-iminodisuccinic acid with Mg, Ca, Mn, Fe, Fe, Co, Ni, Cu, and Zn ions in aqueous 0.1 mol L NaCl solution were studied at 25°C by potentiometric titration. The model for complexation and the stability constants of the different complexes were determined
Canadian Journal of Chemistry, Jul 1, 1986
Syntheses of 11- and 12-hydroxy-(Z)-3-dodecenic, 11- and 12-hydroxy-(Z,Z)-3,6-dodecadienic, and 1... more Syntheses of 11- and 12-hydroxy-(Z)-3-dodecenic, 11- and 12-hydroxy-(Z,Z)-3,6-dodecadienic, and 13-hydroxy-(Z,Z)-5,8-tetradecadienic acids are reported. These unsaturated hydroxy acids are precursors of male-produced macrolide aggregation pheromones of grain beetles of the genera Cryptolestes and Oryzaephilus. The sequence of reactions for synthesis of the hydroxy-(Z)-3 acids was carboxylation of the dilithium salt of 10- or 11-hydroxy undecyne, deconjugation of the resulting carboxylic acids with NaNH2 in THF/liquid ammonia to a mixture of 2,3-allenic and 3-alkynoic acids, and hydrogenation of the mixture with P-2 nickel catalyst. This latter reaction gave only the desired hydroxy-(Z)-3-alkenoic acids. The convergent point in the syntheses of the diunsaturated hydroxy-(Z,Z) acids was the coupling of the dimagnesium salt of 3-butyn-1-ol or 5-hexyn-1-ol to the appropriate functionalized propargylic bromide. The resulting 1,4-diacetylenic alcohols were oxidized with Jones reagent to the corresponding carboxylic acids, which were hydrogenated over P-2 nickel catalyst and deprotected.
ChemInform, Aug 23, 2010
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more 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 Coordination Chemistry, Mar 20, 2008
The persistence of widely used chelating agents EDTA and DTPA in nature has been of concern and t... more The persistence of widely used chelating agents EDTA and DTPA in nature has been of concern and there is a need for ligands to replace them. In a search for environmentally friendly metal chelating ligands for industrial applications, complex formation equilibria of N-bis[2-(1,2-dicarboxyethoxy)ethyl]aspartic acid (BCA6) with Cd(II), Hg(II) and Pb(II) in aqueous 0.1 M NaNO3 solution were studied at 25°C
Journal of Coordination Chemistry, Dec 20, 2009
In a search for environment-friendly metal chelating ligands for industrial applications, the pro... more In a search for environment-friendly metal chelating ligands for industrial applications, the protonation and complex formation equilibria of N-bis[2-(1,2-dicarboxyethoxy)ethyl]aspartic acid (BCA6) with Fe(II), Co(II), and Ni(II) ions in aqueous 0.1 M NaCl solution were studied at 25°C by potentiometric titration. The model for complexation and the stability constants of different complexes were determined for each metal ion using SUPERQUAD. In all cases, complex formation was dominated by stable ML complexes.
Appita Journal, Mar 1, 2006
In a search for environmentally friendly metal chelating ligands the protonation and complex form... more In a search for environmentally friendly metal chelating ligands the protonation and complex formation equilibria of N-bis [2-(1,2-dicarboxyethoxy)ethyl] aspartic acid, N-bis[2-(1,2-dicarboxyethoxy)ethyl]-glycine and N-bis[2-(1,2-dicarboxyethoxy)ethyl]-methylglycine with Mg(II), Ca(II), Mn(II), Fe(III), Cu(II), and Zn(II) in aqueous 0.1 M NaCl solution were studied at 25 C by potentiometric titration. The model of the complexation and the stability constants of the different complexes were determined for each metal ion using the computer program SUPERQUAD. With all metals the complex formation was dominated by stable MLn-6 or MLn-5 complexes. The performance of these new complexing agents was studied in a TCF bleaching of eucalyptus pulp (E. Globulus) via a sequence O-Q-P1-PAA-P2.
Journal of Coordination Chemistry, Aug 10, 2012
ABSTRACT In search for environmentally friendly metal chelating ligands for industrial applicatio... more ABSTRACT In search for environmentally friendly metal chelating ligands for industrial applications, protonation and complex-formation equilibria of iminodisuccinic acid (IDS), 3-hydroxy-2,2’-iminodisuccinic acid (HIDS), N,N’-ethylenediaminedisuccinic acid (EDDS), and oxydisuccinic acid (ODS) with La in aqueous 0.1 mol L NaCl solution were studied at 25 °C by potentiometric titration. The model for complexation and the stability constants of the different complexes were determined using the computer program SUPERQUAD. Complex formation was dominated by stable LaL complexes for all tested ligands.
Holzforschung, Sep 1, 2005
The decomposition mechanism of peracetic acid by free Mn 2q ions and by Mn 2q-diethylenetriaminep... more The decomposition mechanism of peracetic acid by free Mn 2q ions and by Mn 2q-diethylenetriaminepentaacetic acid complexes was studied by UV/Vis, electrospray ionization-time of flight-mass spectrometry (ESI-TOF-MS), electron spin resonance (ESR), and Raman spectroscopy. The experimental results demonstrate that a number of different oxidation states of manganese are involved in the decomposition reaction. Furthermore, the kinetics observed show oscillatory features that are characteristic of autocatalytic processes. Radical pathways were found to play a negligible role in the reaction. Based on the experimental observations, an overall reaction scheme for the decomposition process is proposed.
Journal of the Chemical Society, 2002
ABSTRACT The protonation and complex formation equilibria of N,N′-ethylenediaminedisuccinic acid ... more ABSTRACT The protonation and complex formation equilibria of N,N′-ethylenediaminedisuccinic acid (EDDS) in the isomeric form [S,S] and a mixture of EDDS isomers (25% [S,S], 50% [R,S], 25% [R,R]) with Fe(III), Cu(II), Zn(II) and Mn(II) have been studied in aqueous 0.1 M NaCl solution at 25 °C by potentiometric titrations. The calculations were carried out with the computer program SUPERQUAD.
Holzforschung, Aug 1, 2007
Stabilization of aqueous H 2 O 2 solutions containing small amounts of transition metal impuritie... more Stabilization of aqueous H 2 O 2 solutions containing small amounts of transition metal impurities we.g., Mn(II) and Fe(II)x was studied in terms of UV/Vis and electron spin resonance spectroscopy and oxygen concentration measurements at pH ;11. The results show that aspartic acid diethoxy succinate (AES) could stabilize H 2 O 2 solutions when Mn(II) and Fe(II) were present. Diethylenetriamine pentaacetic acid (DTPA) showed similar behavior, but was not able to stabilize the solutions as efficiently as AES. In the long-term regime, Na-poly-alpha-hydroxyacrylate was almost as effective a stabilizing agent as AES. Na-acrylate-3-allyloxide-2-hydroxy propane Nasulfonate copolymer (Aqualic) could decrease H 2 O 2 decomposition by one order of magnitude, but it was the least efficient stabilizing agent among the substances studied. Furthermore, generation of superoxide radical was not suppressed in the presence of Aqualic.
Journal of Coordination Chemistry, Mar 10, 2011
... Helena Hyvönen a * , Laura Svärd a & Reijo Aksela b pages 1091-1103. ... Hyvönen, H, Oram... more ... Helena Hyvönen a * , Laura Svärd a & Reijo Aksela b pages 1091-1103. ... Hyvönen, H, Orama, M, Saarinen, H and Aksela, R. 2003. Green Chem. , 5: 410 [CrossRef], [Web of Science ®] View all references and HIDS 1616. Hyvönen, H and Aksela, R. 2010. J. Coord. Chem. ...
Tetrahedron Letters, 1990
Solutions comprised of equlmolar concentrations of methyllithium, trimethylstannylllthium and cup... more Solutions comprised of equlmolar concentrations of methyllithium, trimethylstannylllthium and cuprous cyanide as well as reaction of MezCu(CN)Lia with one equivalent of hexamethylditin give MegSn(Me)Cu(CN)Li2 which selectively delivers the R6Sn moiety to a variety of substrates.
Holzforschung, Aug 1, 2007
Stabilization of peracetic acid (PAA) by aspartic acid diethoxy succinate (AES) was studied by el... more Stabilization of peracetic acid (PAA) by aspartic acid diethoxy succinate (AES) was studied by electron spin resonance, UV/Vis spectroscopy, electrospray ionization time-of-flight mass spectrometry and oxygen evolution measurements. The results indicate that Mn(II)-AES complexes may exist in both monomeric and dimeric forms. Dimerization is proposed to proceed via formation of an oxygen bridge between two Mn(II)-AES complexes. The equilibrium between these two forms depends strongly on pH, the monomeric form being favored under acidic conditions, while conditions close to neutral pH favor the dimeric form. In the presence of PAA, the dimer form was oxidized and finally yielded MnO 2. Oxygen evolution measurements were carried out to demonstrate the efficiency of AES in stabilizing PAA solutions containing small amounts of Mn(II) impurities under acidic conditions.
Japan Tappi Journal, 1998
Journal of Coordination Chemistry, Aug 20, 2008
In a search for environmentally friendly metal chelating ligands for industrial applications, the... more In a search for environmentally friendly metal chelating ligands for industrial applications, the protonation and complex formation equilibria of [S,S,S]- and [R,S,R]-isomers of N-bis[2-(1,2-dicarboxyethoxy)ethyl] aspartic acid (BCA6) with Mg(II), Ca(II), Mn(II), Fe(III), Cu(II) and Zn(II) ions in aqueous 0.1 M NaCl solution were studied at 25°C by potentiometric titration. The model for complexation and the stability constants of the different
Journal of Coordination Chemistry, May 11, 2007
In a search for environmentally friendly metal chelating ligands the complex formation equilibria... more In a search for environmentally friendly metal chelating ligands the complex formation equilibria of N-bis[2-(1,2-dicarboxyethoxy)ethyl] glycine (BCA5), N-bis[2-(1,2-dicarboxyethoxy)ethyl] aspartic acid (BCA6), and N-tris[(1,2-dicarboxyethoxy)ethyl] amine (TCA6) with La(III) in aqueous 0.1 M NaCl solution were studied at 25°C by potentiometric titration. The models of the complexation and stability constants of the different complexes were determined using the computer program SUPERQUAD. With TCA6
Journal of Coordination Chemistry, Sep 10, 2005
... The value of the liquid junction coefficient, j OH , valid in basic solutions, was determined... more ... The value of the liquid junction coefficient, j OH , valid in basic solutions, was determined periodically. ... In the micromolar concentration area, dilution of the solution increases the lower pH limit of the effective chelation region to more basic values. View larger version(30K). ...