Works by Koppel, Ilmar

Results: 39

Boratabenzene Anions C5B(CN)6− and C5B(CF3)6− and the Superacidic Properties of their Conjugate Acids.

Published in:

ChemPhysChem, 2009, v. 10, n. 3, p. 499, doi. 10.1002/cphc.200800305

By:

Kütt, Agnes;
Koppel, Ivar;
Koppel, Ilmar A.;
Leito, Ivo

Publication type:

Article

Stereoelectronic, Strain, and Medium Effects on the Protonation of Cubylamine, a Janus-like Base ( This work was supported by grants BQU2000-1497 (Spanish DGES) and 5226 (Estonian Science Foundation) and by a Joint Project CSIC-Estonian Academy of Sciences. The Reactivity of the Strained Cage Molecules. )

Published in:

Angewandte Chemie, 2003, v. 115, n. 20, p. 2383

By:

José-Luis M. Abboud;
Ilmar A. Koppel;
Ibon Alkorta;
Ernest W. Della;
Paul Müller;
Juan Z. Dávalos;
Peeter Burk;
Ivar Koppel;
Viljar Pihl;
Esther Quintanilla

Publication type:

Article

Some small weakly coordinating anions based on carboranes.

Published in:

Proceedings of the Estonian Academy of Sciences, Chemistry, 2006, v. 55, n. 3, p. 145

By:

Lipping, Lauri;
Koppel, Ilmar A.;
Koppel, Ivar;
Leito, Ivo

Publication type:

Article

Self-consistent acidity and basicity scales in nonaqueous solvents.

Published in:

Proceedings of the Estonian Academy of Sciences, Chemistry, 2005, v. 54, n. 2, p. 94

By:

Leito, Ivo;
Kaljurand, Ivari;
Rodima, Toomas;
Kütt, Agnes;
Pihl, Aino;
Rõõm, Eva-Ingrid;
Sooväli, Lilli;
Mäemets, Vahur;
Pihl, Viljar;
Koppel, Ilmar A.

Publication type:

Article

Solvatochromism of fullerene C60 in solvent mixtures: application of the preferential solvation model.

Published in:

Proceedings of the Estonian Academy of Sciences, Chemistry, 2002, v. 51, n. 1, p. 3

By:

Pille, Urmas;
Herodes, Koit;
Leito, Ivo;
Burk, Peeter;
Pihl, Viljar;
Koppel, Ilmar

Publication type:

Article

Superacidity of neutral Brönsted acids in gas phase.

Published in:

Journal of Computational Chemistry, 1996, v. 17, n. 1, p. 30, doi. 10.1002/(SICI)1096-987X(19960115)17:1<30::AID-JCC3>3.0.CO;2-1

By:

Burk, Peeter;
Koppel, Ilmar A.;
Koppel, Ivar;
Yagupolskii, Lev M.;
Taft, Robert W.

Publication type:

Article

17O NMR studies of ortho-substituent effects in substituted phenyl tosylates.

Published in:

Magnetic Resonance in Chemistry, 2012, v. 50, n. 10, p. 696, doi. 10.1002/mrc.3864

By:

Nummert, Vilve;
Mäemets, Vahur;
Piirsalu, Mare;
Koppel, Ilmar A.

Publication type:

Article

Stereoelectronic, Strain, and Medium Effects on the Protonation of Cubylamine, a Janus-like Base ( This work was supported by grants BQU2000-1497 (Spanish DGES) and 5226 (Estonian Science Foundation) and by a Joint Project CSIC-Estonian Academy of Sciences. The Reactivity of the Strained Cage Molecules. )

Published in:

Angewandte Chemie International Edition, 2003, v. 42, n. 20, p. 2281, doi. 10.1002/anie.200350993

By:

José-Luis M. Abboud;
Ilmar A. Koppel;
Ibon Alkorta;
Ernest W. Della;
Paul Müller;
Juan Z. Dávalos;
Peeter Burk;
Ivar Koppel;
Viljar Pihl;
Esther Quintanilla

Publication type:

Article

Protonation of Cubane in the Gas Phase: A High-Level Ab Initio and DFT Study.

Published in:

Angewandte Chemie International Edition, 2003, v. 42, n. 9, p. 1044, doi. 10.1002/anie.200390269

By:

Abboud, José-Luis M.;
Koppel, Ilmar A.;
Dávalos, Juan Z.;
Burk, Peeter;
Koppel, Ivar;
Quintanilla, Esther

Publication type:

Article

Solution and Gas-Phase Acidities of all-trans (all-E) Retinoic Acid: An Experimental and Computational Study.

Published in:

Chemistry - A European Journal, 2015, v. 21, n. 31, p. 11238, doi. 10.1002/chem.201500717

By:

Abboud, José ‐ Luis M.;
Koppel, Ilmar A.;
Uggerud, Einar;
Leito, Ivo;
Koppel, Ivar;
Sekiguchi, Osamu;
Kaupmees, Karl;
Saame, Jaan;
Kütt, Karl;
Mishima, Masaaki

Publication type:

Article

A New Class of Organosuperbases, N-Alkyl- and N-Aryl-1,3-dialkyl-4,5-dimethylimidazol-2-ylidene Amines: Synthesis, Structure, p KBH+ Measurements, and Properties.

Published in:

Chemistry - A European Journal, 2012, v. 18, n. 12, p. 3621, doi. 10.1002/chem.201102249

By:

Kunetskiy, Roman A.;
Polyakova, Svetlana M.;
Vavřík, Jiří;
Císařová, Ivana;
Saame, Jaan;
Nerut, Eva Roos;
Koppel, Ivar;
Koppel, Ilmar A.;
Kütt, Agnes;
Leito, Ivo;
Lyapkalo, Ilya M.

Publication type:

Article

Basicity Limits of Neutral Organic Superbases.

Published in:

Angewandte Chemie, 2015, v. 127, n. 32, p. 9394, doi. 10.1002/ange.201503345

By:

Leito, Ivo;
Koppel, Ilmar A.;
Koppel, Ivar;
Kaupmees, Karl;
Tshepelevitsh, Sofja;
Saame, Jaan

Publication type:

Article

Pentakis(trifluoromethyl)benzenediazonium Cation: A Useful Building Block for the Syntheis of Trifluoromethyl-Substituted Derivatives.

Published in:

ChemPlusChem, 2013, v. 78, n. 9, p. 932, doi. 10.1002/cplu.201300160

By:

Kütt, Agnes;
Werner, Franz;
Kaljurand, Ivari;
Leito, Ivo;
Koppel, Ilmar A.

Publication type:

Article

Brønsted Basicities of Diamines in the Gas Phase, Acetonitrile, and Tetrahydrofuran.

Published in:

Chemistry - A European Journal, 2007, v. 13, n. 27, p. 7631, doi. 10.1002/chem.200700097

By:

Rõõm, Eva-Ingrid;
Kütt, Agnes;
Kaljurand, Ivari;
Koppel, Ivar;
Leito, Ivo;
Koppel, Ilmar A.;
Mishima, Masaaki;
Goto, Kenta;
Miyahara, Yuji

Publication type:

Article

PM3 semiempirical calculations of lithium-cation and proton affinities for XYZPO and XYSO.

Published in:

International Journal of Quantum Chemistry, 1996, v. 59, n. 5, p. 409, doi. 10.1002/(SICI)1097-461X(1996)59:5<409::AID-QUA5>3.0.CO;2-1

By:

Gal, Jean-François;
Koppel, Ilmar;
Kurg, Riho;
Maria, Pierre-Charles

Publication type:

Article

Theoretical study of structure and basicity of some alkali metal oxides, hydroxides, and amides.

Published in:

International Journal of Quantum Chemistry, 1994, v. 51, n. 5, p. 313, doi. 10.1002/qua.560510507

By:

Burk, Peeter;
Koppel, Ilmar

Publication type:

Article

Critical test of.

Published in:

International Journal of Quantum Chemistry, 1993, v. 48, n. S27, p. 633, doi. 10.1002/qua.560480857

By:

Burk, Peeter;
Herodes, Koit;
Koppel, Ivar;
Koppel, Ilmar

Publication type:

Article

Basicity Limits of Neutral Organic Superbases.

Published in:

Angewandte Chemie International Edition, 2015, v. 54, n. 32, p. 9262, doi. 10.1002/anie.201503345

By:

Leito, Ivo;
Koppel, Ivar;
Koppel, Ilmar A.;
Tshepelevitsh, Sofja;
Saame, Jaan;
Kaupmees, Karl

Publication type:

Article

Effect of charged and ortho substituents on 17O NMR chemical shifts of substituted phenyl tosylates in DMSO.

Published in:

Journal of Physical Organic Chemistry, 2018, v. 31, n. 12, p. N.PAG, doi. 10.1002/poc.3870

By:

Nummert, Vilve;
Piirsalu, Mare;
Toom, Lauri;
Kesvatera, Tõnu;
Leito, Ivo;
Koppel, Ilmar A.

Publication type:

Article

Effects of neutral and charged substituents on the infrared carbonyl stretching frequencies in phenyl and alkyl benzoates in DMSO.

Published in:

Journal of Physical Organic Chemistry, 2017, v. 30, n. 3, p. n/a, doi. 10.1002/poc.3608

By:

Nummert, Vilve;
Piirsalu, Mare;
Vahur, Signe;
Toom, Lauri;
Leito, Ivo;
Koppel, Ilmar A.

Publication type:

Article

Gas-phase acidity of bis[(perfluoroalkyl)sulfonyl]imides. Effects of the perfluoroalkyl group on the acidity.

Published in:

Journal of Physical Organic Chemistry, 2014, v. 27, n. 8, p. 676, doi. 10.1002/poc.3317

By:

Zhang, Min;
Sonoda, Takaaki;
Mishima, Masaaki;
Honda, Tsunetoshi;
Leito, Ivo;
Koppel, Ilmar A.;
Bonrath, Werner;
Netscher, Thomas

Publication type:

Article

Additivity of substituent effects on the acidity of alcohols.

Published in:

Journal of Physical Organic Chemistry, 2013, v. 26, n. 6, p. 467, doi. 10.1002/poc.3110

By:

Abboud, José ‐ Luis M.;
Koppel, Ilmar A.;
Koppel, Ivar

Publication type:

Article

Prediction of ortho substituent effect in alkaline hydrolysis of substituted phenyl benzoates in aqueous acetonitrile.

Published in:

Journal of Physical Organic Chemistry, 2013, v. 26, n. 4, p. 352, doi. 10.1002/poc.3096

By:

Nummert, Vilve;
Piirsalu, Mare;
Koppel, Ilmar A.

Publication type:

Article

The basicity of substituted N, N-dimethylanilines in solution and in the gas phase The basicity of substituted N, N-dimethylanilines in solution and in the gas phase.

Published in:

Journal of Physical Organic Chemistry, 2013, v. 26, n. 2, p. 171, doi. 10.1002/poc.2956

By:

Kaljurand, Ivari;
Lilleorg, Roman;
Murumaa, Algis;
Mishima, Masaaki;
Burk, Peeter;
Koppel, Ivar;
Koppel, Ilmar A.;
Leito, Ivo

Publication type:

Article

Acidities of strong neutral Brønsted acids in different media Acidities of strong neutral Brønsted acids in different media.

Published in:

Journal of Physical Organic Chemistry, 2013, v. 26, n. 2, p. 162, doi. 10.1002/poc.2946

By:

Raamat, Elin;
Kaupmees, Karl;
Ovsjannikov, Gea;
Trummal, Aleksander;
Kütt, Agnes;
Saame, Jaan;
Koppel, Ivar;
Kaljurand, Ivari;
Lipping, Lauri;
Rodima, Toomas;
Pihl, Viljar;
Koppel, Ilmar A.;
Leito, Ivo

Publication type:

Article

Influence of ortho substituents on.

Published in:

Journal of Physical Organic Chemistry, 2011, v. 24, n. 7, p. 539, doi. 10.1002/poc.1784

By:

Nummert, Vilve;
Mäemets, Vahur;
Piirsalu, Mare;
Koppel, Ilmar A.

Publication type:

Article

Influence of solvent on the ortho substituent effect in the alkaline hydrolysis of phenyl esters of substituted benzoic acids.

Published in:

Journal of Physical Organic Chemistry, 2010, v. 23, n. 6, p. 497, doi. 10.1002/poc.1628

By:

Nummert, Vilve;
Piirsalu, Mare;
Koppel, Ilmar A.

Publication type:

Article

Effect of ortho substituents on carbonyl carbon 13C NMR chemical shifts in substituted phenyl benzoates.

Published in:

Journal of Physical Organic Chemistry, 2009, v. 22, n. 12, p. 1155, doi. 10.1002/poc.1569

By:

Nummert, Vilve;
Piirsalu, Mare;
Mäemets, Vahur;
Vahur, Signe;
Koppel, Ilmar A.

Publication type:

Article

Feasibility of the spontaneous gas-phase proton transfer equilibria between neutral Brønsted acids and Brønsted bases.

Published in:

Journal of Physical Organic Chemistry, 2008, v. 21, n. 7/8, p. 571, doi. 10.1002/poc.1322

By:

Burk, Peeter;
Koppel, Ivar;
Trummal, Aleksander;
Koppel, Ilmar A.

Publication type:

Article

Variation of the temperature-dependent substituent effects with solvent in alkaline hydrolysis of substituted phenyl and alkyl benzoates and phenyl tosylates.

Published in:

Journal of Physical Organic Chemistry, 2007, v. 20, n. 10, p. 778, doi. 10.1002/poc.1246

By:

Nummert, Vilve;
Piirsalu, Mare;
Koppel, Ilmar A.

Publication type:

Article

Influence of substituents on the infrared stretching frequencies of carbonyl group in esters of benzoic acid.

Published in:

Journal of Physical Organic Chemistry, 2006, v. 19, n. 10, p. 654, doi. 10.1002/poc.1112

By:

Nummert, Vilve;
Travnikova, Oksana;
Vahur, Signe;
Leito, Ivo;
Piirsalu, Mare;
Mäemets, Vahur;
Koppel, Ivar;
Koppel, Ilmar A.

Publication type:

Article

Kinetic study of hydrolysis of benzoates. Part XXIV—Variation of the ortho substituent effect with solvent in the alkaline hydrolysis of substituted phenyl benzoates.

Published in:

Journal of Physical Organic Chemistry, 2005, v. 18, n. 11, p. 1138, doi. 10.1002/poc.967

By:

Nummert, Vilve;
Piirsalu, Mare;
Mäemets, Vahur;
Koppel, Ilmar

Publication type:

Article

UV-Vis spectroscopic study of the hydrophilic and solvatochromic 4-[2,6-diphenyl-4-(pyridin-4-yl)pyridinium-1-yl]-2,6-bis(pyridin-3-yl)phenolate betaine dye in aqueous tetra-n-butylammonium bromide.

Published in:

Journal of Physical Organic Chemistry, 2005, v. 18, n. 10, p. 1013, doi. 10.1002/poc.958

By:

Herodes, Koit;
Leito, Ivo;
Koppel, Juta;
Reichardt, Christian;
Koppel, Ilmar A.

Publication type:

Article

UVvisible spectroscopic study of the hydrophilic and solvatochromic 4-[2,6-diphenyl-4-(pyridin-4-yl)pyridinium-1-yl]-2,6-bis(pyridin-3-yl)phenolate betaine dye in eight binary solvent mixtures.

Published in:

Journal of Physical Organic Chemistry, 2003, v. 16, n. 9, p. 626

By:

Koit Herodes;
Juta Koppel;
Christian Reichardt;
Ilmar A. Koppel

Publication type:

Article

Solute-solvent and solvent-solvent interactions in binary solvent mixtures. Part 8. The ET(30) polarity of binary mixtures of formamides with hydroxylic solvents.

Published in:

Journal of Physical Organic Chemistry, 1999, v. 12, n. 2, p. 109, doi. 10.1002/(SICI)1099-1395(199902)12:2<109::AID-POC97>3.0.CO;2-L

By:

Herodes, Koit;
Leito, Ivo;
Koppel, Ilmar;
Rosés, Martí

Publication type:

Article

Solute-solvent and solvent-solvent interactions in binary solvent mixtures. 2. Effect of temperature on the ET(30) polarity parameter of dipolar hydrogen bond acceptor-hydrogen bond donor mixtures.

Published in:

Journal of Physical Organic Chemistry, 1996, v. 9, n. 6, p. 403, doi. 10.1002/(SICI)1099-1395(199606)9:6<403::AID-POC799>3.0.CO;2-D

By:

Bosch, Elisabeth;
Rosés, Martí;
Herodes, Koit;
Koppel, Ilmar;
Leito, Ivo;
Koppel, Ivar;
Taal, Veiko

Publication type:

Article

Basicity of 3-aminopropionamidine derivatives in water and dimethyl sulphoxide. Implication for a pivotal step in the synthesis of distamycin A analogues.

Published in:

Journal of Physical Organic Chemistry, 1996, v. 9, n. 5, p. 265, doi. 10.1002/(SICI)1099-1395(199605)9:5<265::AID-POC780>3.0.CO;2-4

By:

Koppel, Ilmar;
Koppel, Juta;
Leito, Ivo;
Grehn, Leif

Publication type:

Article

Quantitative description of acidity of XOH compounds in the gas phase and dimethyl sulphoxide with use of HOMO energies of XO− anions.

Published in:

Journal of Physical Organic Chemistry, 1995, v. 8, n. 5, p. 364, doi. 10.1002/poc.610080509

By:

Vlasov, Vladislav M.;
Koppel, Ilmar A.;
Burk, Peeter;
Koppel, Ivar

Publication type:

Article

Rechecking of the equilibrium gas-phase basicity scale for low-basicity compounds using fourier transform ion cyclotron resonance spectrometry.

Published in:

Journal of Physical Organic Chemistry, 1994, v. 7, n. 12, p. 717, doi. 10.1002/poc.610071210

By:

Koppel, Ilmar A.;
Anvia, Frederick;
Taft, Robert W.

Publication type:

Article

Works by Koppel, Ilmar

Boratabenzene Anions C<sub>5</sub>B(CN)<sub>6</sub><sup>−</sup> and C<sub>5</sub>B(CF<sub>3</sub>)<sub>6</sub><sup>−</sup> and the Superacidic Properties of their Conjugate Acids.

Some small weakly coordinating anions based on carboranes.

Self-consistent acidity and basicity scales in nonaqueous solvents.

Solvatochromism of fullerene C60 in solvent mixtures: application of the preferential solvation model.

Superacidity of neutral Brönsted acids in gas phase.

<sup>17</sup>O NMR studies of ortho-substituent effects in substituted phenyl tosylates.

Protonation of Cubane in the Gas Phase: A High-Level Ab Initio and DFT Study.

Solution and Gas-Phase Acidities of all-trans (all-E) Retinoic Acid: An Experimental and Computational Study.

A New Class of Organosuperbases, N-Alkyl- and N-Aryl-1,3-dialkyl-4,5-dimethylimidazol-2-ylidene Amines: Synthesis, Structure, p K<sub>BH+</sub> Measurements, and Properties.

Basicity Limits of Neutral Organic Superbases.

Pentakis(trifluoromethyl)benzenediazonium Cation: A Useful Building Block for the Syntheis of Trifluoromethyl-Substituted Derivatives.

Brønsted Basicities of Diamines in the Gas Phase, Acetonitrile, and Tetrahydrofuran.

PM3 semiempirical calculations of lithium-cation and proton affinities for XYZPO and XYSO.

Theoretical study of structure and basicity of some alkali metal oxides, hydroxides, and amides.

Critical test of.

Basicity Limits of Neutral Organic Superbases.

Effect of charged and ortho substituents on <sup>17</sup>O NMR chemical shifts of substituted phenyl tosylates in DMSO.

Effects of neutral and charged substituents on the infrared carbonyl stretching frequencies in phenyl and alkyl benzoates in DMSO.

Gas-phase acidity of bis[(perfluoroalkyl)sulfonyl]imides. Effects of the perfluoroalkyl group on the acidity.

Additivity of substituent effects on the acidity of alcohols.

Prediction of ortho substituent effect in alkaline hydrolysis of substituted phenyl benzoates in aqueous acetonitrile.

The basicity of substituted N, N-dimethylanilines in solution and in the gas phase The basicity of substituted N, N-dimethylanilines in solution and in the gas phase.

Acidities of strong neutral Brønsted acids in different media Acidities of strong neutral Brønsted acids in different media.

Influence of ortho substituents on.

Influence of solvent on the ortho substituent effect in the alkaline hydrolysis of phenyl esters of substituted benzoic acids.

Effect of ortho substituents on carbonyl carbon <sup>13</sup>C NMR chemical shifts in substituted phenyl benzoates.

Feasibility of the spontaneous gas-phase proton transfer equilibria between neutral Brønsted acids and Brønsted bases.

Variation of the temperature-dependent substituent effects with solvent in alkaline hydrolysis of substituted phenyl and alkyl benzoates and phenyl tosylates.

Influence of substituents on the infrared stretching frequencies of carbonyl group in esters of benzoic acid.

Kinetic study of hydrolysis of benzoates. Part XXIV—Variation of the ortho substituent effect with solvent in the alkaline hydrolysis of substituted phenyl benzoates.

UV-Vis spectroscopic study of the hydrophilic and solvatochromic 4-[2,6-diphenyl-4-(pyridin-4-yl)pyridinium-1-yl]-2,6-bis(pyridin-3-yl)phenolate betaine dye in aqueous tetra-n-butylammonium bromide.

UVvisible spectroscopic study of the hydrophilic and solvatochromic 4-[2,6-diphenyl-4-(pyridin-4-yl)pyridinium-1-yl]-2,6-bis(pyridin-3-yl)phenolate betaine dye in eight binary solvent mixtures.

Solute-solvent and solvent-solvent interactions in binary solvent mixtures. Part 8. The E<sub>T</sub>(30) polarity of binary mixtures of formamides with hydroxylic solvents.

Solute-solvent and solvent-solvent interactions in binary solvent mixtures. 2. Effect of temperature on the E<sub>T</sub>(30) polarity parameter of dipolar hydrogen bond acceptor-hydrogen bond donor mixtures.

Basicity of 3-aminopropionamidine derivatives in water and dimethyl sulphoxide. Implication for a pivotal step in the synthesis of distamycin A analogues.

Quantitative description of acidity of XOH compounds in the gas phase and dimethyl sulphoxide with use of HOMO energies of XO<sup>−</sup> anions.

Rechecking of the equilibrium gas-phase basicity scale for low-basicity compounds using fourier transform ion cyclotron resonance spectrometry.