I. Koppel

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Critical Test of Some Computational Chemistry Methods for Prediction of Gas-Phase Acidities and Basicities.

P. Burk, E. Toomsalu, I. Koppel, 2013, Journal of chemical theory and computation.

IEF-PCM calculations of absolute pKa for substituted phenols in dimethyl sulfoxide and acetonitrile solutions.

É. Lippmaa, A. Rummel, A. Trummal, 2009, The journal of physical chemistry. A.

Acidities of strong neutral Brønsted acids in different media

A. Trummal, I. Leito, I. Koppel, 2013 .

Solution and gas-phase acidities of all-trans (all-E) retinoic acid: an experimental and computational study.

J. Abboud, I. Leito, I. Koppel, 2015, Chemistry.

EFFECTS OF ALKYL AND FLUOROALKYL SUBSTITUTION ON THE HETEROLYTIC AND HOMOLYTIC BOND DISSOCIATION ENERGIES OF PROTONATED AMINES

R. Taft, I. Koppel, J. Beauchamp, 1977 .

Basicity of Guanidines with Heteroalkyl Side Chains in Acetonitrile

M. Eckert-Maksić, I. Koppel, A. Kütt, 2008 .

Equilibrium acidities of superacids.

I. Leito, I. Koppel, H. Willner, 2011, The Journal of organic chemistry.

Comparison of brönsted acidities of neutral NH-acids in gas phase, dimethyl sulfoxide and water

V. M. Vlasov, R. Taft, J. Gal, 1998 .

Boratabenzene Anions C5B(CN)6(-) and C5B(CF3)6(-) and the superacidic properties of their conjugate acids.

I. Leito, I. Koppel, A. Kütt, 2009, Chemphyschem : a European journal of chemical physics and physical chemistry.

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

P. Burk, I. Koppel, 1994 .

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

R. Taft, I. Koppel, F. Anvia, 1994 .

A comprehensive self-consistent spectrophotometric acidity scale of neutral Brønsted acids in acetonitrile.

V. M. Vlasov, I. Leito, I. Koppel, 2006, The Journal of organic chemistry.

A new class of organosuperbases, N-alkyl- and N-aryl-1,3-dialkyl-4,5-dimethylimidazol-2-ylidene amines: synthesis, structure, pK(BH+) measurements, and properties.

Eva Roos Nerut, I. Císařová, I. Leito, 2012, Chemistry.

17 O and 1H NMR chemical shifts ofhydroxide and hydronium ion in aqueous solutions of strongelectrolytes

I. Koppel, V. Mäemets, 1997 .

Prediction of ortho substituent effect in alkaline hydrolysis of phenyl esters of substituted benzoic acids in aqueous acetonitrile

I. Koppel, Vilve Nummert, Mare Piirsalu, 2013 .

KINETIC STUDY OF HYDROLYSIS OF BENZOATES. PART XXV. Ortho SUBSTITUENT EFFECT IN ALKALINE HYDROLYSIS OF PHENYL ESTERS OF SUBSTITUTED BENZOIC ACIDS IN WATER

O. Travnikova, I. Koppel, S. Vahur, 2006 .

Acid-base equilibria in nonpolar media. 2.(1) Self-consistent basicity scale in THF solution ranging from 2-methoxypyridine to EtP(1)(pyrr) phosphazene.

I. Leito, I. Koppel, I. Kaljurand, 2002, The Journal of organic chemistry.

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

T. Netscher, W. Bonrath, I. Leito, 2014 .

Gas phase basicities and relative proton affinities of compounds between water and ammonia from pulsed ion cyclotron resonance thermal equilibriums measurements

R. Taft, R. T. McIver, I. Koppel, 1977 .

Pentakis(trifluoromethyl)phenyl, a sterically crowded and electron-withdrawing group: synthesis and acidity of pentakis(trifluoromethyl)benzene, -toluene, -phenol, and -aniline.

G. Röschenthaler, M. Médebielle, I. Leito, 2008, The Journal of organic chemistry.

Gas-Phase Acidity of Polyfluorinated Hydrocarbons. Effects of Fluorine and the Perfluoroalkyl Group on Acidity

J. Abboud, I. Koppel, Min Zhang, 2014 .

The intrinsic (gas-phase) acidities of bridgehead alcohols An experimental (FT-ICR) and computational study

J. Abboud, J. Dávalos, I. Koppel, 2007 .

Lithium-cation and proton affinities of sulfoxides and sulfones: A fourier transform ion cyclotron resonance study

J. Gal, P. Maria, I. Koppel, 1997 .

Revised and Expanded Scale of Gas-Phase Lithium Cation Basicities. An Experimental and Theoretical Study

R. Taft, J. Abboud, J. Gal, 2000 .

Gas-Phase Acidities of Some Neutral Brønsted Superacids: A DFT and ab Initio Study

I. Leito, P. Burk, I. Koppel, 2000 .

The Gas-Phase Acidities of Very Strong Neutral Bronsted Acids

R. Taft, D. Desmarteau, Shizheng Zhu, 1994 .

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

I. Leito, I. Koppel, L. Grehn, 1996 .

Additivity of substituent effects on the acidity of alcohols

J. Abboud, I. Koppel, I. Koppel, 2013 .

Pentakis(trifluoromethyl)phenol from Nitrobenzene

I. Koppel, A. Kütt, 2014 .

A unified view to Brønsted acidity scales: do we need solvated protons?† †Electronic supplementary information (ESI) available: Detailed description of the equilibria, activities, anchoring approach and experiments. See DOI: 10.1039/c7sc01424d Click here for additional data file.

I. Krossing, I. Leito, I. Koppel, 2017, Chemical Science.

Acidity of di- and triprotected hydrazine derivatives in dimethyl sulfoxide and aspects of their alkylation.

U. Ragnarsson, U. Mäeorg, I. Koppel, 2005, The Journal of organic chemistry.

Acidity of imidodicarbonates and tosylcarbamates in dimethyl sulfoxide. Correlation with yields in the Mitsunobu reaction

U. Ragnarsson, I. Koppel, L. Grehn, 1991 .

Guanidinophosphazenes: design, synthesis, and basicity in THF and in the gas phase.

G. Röschenthaler, I. Leito, I. Koppel, 2005, Journal of the American Chemical Society.

Acid-base equilibria in nonpolar media. 4. Extension of the self-consistent basicity scale in THF medium. Gas-phase basicities of phosphazenes.

I. Leito, I. Koppel, I. Kaljurand, 2003, The Journal of organic chemistry.

The Influence of the Solvent on Organic Reactivity

I. Koppel, V. Palm, 1972 .

The immense acidifying effect of the supersubstituent NSO2CF3 on the acidity of amides and amidines of benzoic acids in acetonitrile

I. Leito, I. Koppel, I. Kaljurand, 2002 .

Experimental Basicities of Phosphazene, Guanidinophosphazene, and Proton Sponge Superbases in the Gas Phase and Solution.

J. Sundermeyer, I. Leito, I. Koppel, 2016, The journal of physical chemistry. A.

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

I. Leito, P. Burk, I. Koppel, 2013 .

Brønsted basicities of diamines in the gas phase, acetonitrile, and tetrahydrofuran.

Y. Miyahara, I. Leito, I. Koppel, 2007, Chemistry.

Extension of the self-consistent spectrophotometric basicity scale in acetonitrile to a full span of 28 pKa units: unification of different basicity scales.

I. Leito, I. Koppel, A. Kütt, 2005, The Journal of organic chemistry.

Revision of the gas-phase acidity scale below 300 kcal mol(-1).

Min Zhang, I. Leito, I. Koppel, 2009, The journal of physical chemistry. A.

17O NMR study of ortho and alkyl substituent effects in substituted phenyl and alkyl esters of benzoic acids

I. Koppel, S. Vahur, V. Mäemets, 2011 .

The Thermodynamic Stability of Adamantylideneadamantane and Its Proton- and Electron-Exchanges. Comparison with Simple Alkenes

D. Lenoir, J. Abboud, J. Dávalos, 2016 .

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

I. Koppel, V. Mäemets, Vilve Nummert, 2005 .

Acidity of Strong Acids in Water and Dimethyl Sulfoxide.

A. Trummal, I. Leito, I. Koppel, 2016, The journal of physical chemistry. A.

Acid-Base Equilibria in Nonpolar Media. 1. A Spectrophotometric Method for Acidity Measurements in Heptane.

V. M. Vlasov, I. Leito, I. Koppel, 1997, The Journal of organic chemistry.

Synthesis and cathodic cleavage of a set of substituted benzenesulfonamides including the corresponding tert-butyl sulfonylcarbamates: pKa of sulfonamides

U. Ragnarsson, I. Leito, I. Koppel, 1995 .

Synthesis of N-aryl-substituted iminophosphoranes and NMR spectroscopic investigation of their acid–base properties in acetonitrile

I. Koppel, T. Rodima, V. Mäemets, 2000 .

Superacidity of closo-dodecaborate-based Brønsted acids: a DFT study.

I. Krossing, I. Leito, I. Koppel, 2015, The journal of physical chemistry. A.

Some small weakly coordinating anions based on carboranes

I. Leito, I. Koppel, I. Koppel, 2006, Proceedings of the Estonian Academy of Sciences. Chemistry.

Basicity Limits of Neutral Organic Superbases.

I. Leito, I. Koppel, Karl Kaupmees, 2015, Angewandte Chemie.

UV-visible 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

C. Reichardt, I. Koppel, K. Herodes, 2003 .

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

I. Leito, M. Rosés, I. Koppel, 1999 .

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

I. Leito, E. Bosch, M. Rosés, 1996 .

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

I. Leito, C. Reichardt, I. Koppel, 2005 .

Gas-phase basicities around and below water revisited.

J. Abboud, I. Leito, J. Dávalos, 2010, The journal of physical chemistry. A.

Relativistic effects on acidities and basicities of Brønsted acids and bases containing gold.

P. Burk, I. Koppel, I. Koppel, 2013, Physical chemistry chemical physics : PCCP.

Critical test of performance of B3LYP functional for prediction of gas-phase acidities and basicities

I. Leito, O. Travnikova, P. Burk, 2000 .

Calculations of pKa of superacids in 1,2-dichloroethane.

É. Lippmaa, A. Rummel, A. Trummal, 2011, The journal of physical chemistry. A.

Experimental Basicities of Superbasic Phosphonium Ylides and Phosphazenes.

I. Leito, Tõiv Haljasorg, I. Koppel, 2016, The Journal of organic chemistry.

Intrinsic Basicities of Phosphorus Imines and Ylides: A Theoretical Study

P. Burk, I. Koppel, K. Herodes, 2001 .

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

I. Koppel, Vilve Nummert, Mare Piirsalu, 2013 .

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

I. Koppel, Vilve Nummert, Mare Piirsalu, 2010 .

Experimental gas-phase basicity scale of superbasic phosphazenes.

I. Leito, I. Koppel, A. Kütt, 2007, The journal of physical chemistry. A.

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

I. Koppel, Vilve Nummert, Mare Piirsalu, 2007 .

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

I. Leito, O. Travnikova, I. Koppel, 2006 .

Acidity of benzoylcarbamates in dimethyl sulfoxide. Confirmation of mixed N/O alkylation in the Mitsunobu reaction

U. Ragnarsson, I. Leito, I. Koppel, 1993 .

Gas-Phase Acidities of α- and α,α-SO2CF3-Substituted Toluenes. Varying Resonance Demand in the Electron-Rich System

I. Koppel, Min Zhang, M. Mishima, 2013 .

Comparison of Brønsted acidities of neutral CH acids in gas phase and dimethyl sulfoxide

V. M. Vlasov, I. Leito, I. Koppel, 2000 .

Critical test of PM3 calculated gas-phase acidities

Peeter Burk, Ilmar A. Koppel, P. Burk, 1993 .

Critical test of PM3‐calculated proton affinities

Koit Herodes, Peeter Burk, Ilmar A. Koppel, 1993 .

Comparison of Broensted Acidities of Neutral CH Acids in Gas Phase and Dimethyl Sulfoxide.

V. M. Vlasov, I. Leito, I. Koppel, 2000 .

Thermodynamic Acidity of (CF3)3CH and 1H-Undecafluorobicyclo[2.2.1]heptane: The Concept of Anionic (Fluorine) Hyperconjugation

R. Taft, I. Koppel, V. Pihl, 1994 .

Regarding the inherent dependence of resonance effects of strongly conjugated substituents on electron demand

R. Taft, M. Berthelot, J. Abboud, 1988 .

Superacidity of neutral Brönsted acids in gas phase

R. Taft, P. Burk, I. Koppel, 1996 .

Aromaticity of Substituted Cyclopropenes - A Theoretical-Study

J. Abboud, P. Burk, I. Koppel, 1996 .

Stereoelectronic, strain, and medium effects on the protonation of cubylamine, a Janus-like base.

E. W. Della, J. Abboud, J. Dávalos, 2003, Angewandte Chemie.

Spectrophotometric Acidity Scale of Strong Neutral Brønsted Acids in Acetonitrile

V. M. Vlasov, I. Leito, I. Koppel, 1998 .

An AM1 and PM3 study of hexafluoroacetylacetone

P. Burk, I. Koppel, 1993 .

Theoretical study of prototropic tautomerism and acidity of tris(fluorosulfonyl)methane

P. Burk, I. Koppel, F. Anvia, 1994 .

Acidities of substituted acetic acids

R. Taft, I. Koppel, R. D. Topsom, 1988 .

Proton affinities of substituted cyanides

R. Taft, C. Lebrilla, I. Koppel, 1986 .

Effects of alkyl and fluoroalkyl substitution on the heterolytic and homolytic bond dissociation energies of protonated amines

R. Taft, I. Koppel, J. Beauchamp, 1977 .

PM3 semiempirical calculations of lithium‐cation and proton affinities for XYZPO and XYSO2 compounds

J. Gal, P. Maria, I. Koppel, 1996 .

Gas-Phase Lithium Cation Basicity: Revisiting the High Basicity Range by Experiment and Theory

I. Leito, J. Gal, C. Mayeux, 2014, Journal of The American Society for Mass Spectrometry.

Aromaticity of Substituted Cyclopropenes: A Theoretical Study

J. Abboud, P. Burk, I. Koppel, 1996 .

Influence of ortho substituents on 17O NMR chemical shifts in phenyl esters of substituted benzoic acids

I. Koppel, V. Mäemets, Vilve Nummert, 2011 .

The enormous acidifying effect of the supersubstituent NSO2CF3 on the acidity of derivatives of benzenesulfonamide and toluene-p-sulfonamide in the gas phase and in dimethyl sulfoxide

I. Leito, I. Koppel, I. Koppel, 2001 .

Spectrophotometric Acidity Scale of Strong Neutral Broenstedt Acids in Acetonitrile.

V. M. Vlasov, I. Leito, I. Koppel, 1999 .

17 O and 1H chemical shifts of water in solutions of some ammonium salts: evaluation of the anionic effect on the 17O and 1H chemical shifts of water in aqueous solutions of mineral acids

I. Koppel, V. Mäemets, 1996 .

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

I. Leito, I. Koppel, F. Werner, 2013, ChemPlusChem.

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

I. Leito, I. Koppel, K. Herodes, 2002, Proceedings of the Estonian Academy of Sciences. Chemistry.

Effect of ions on the 17O and 1H NMR chemical shifts of water

I. Koppel, V. Mäemets, 1998 .

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

I. Leito, I. Koppel, S. Vahur, 2017 .

Acid-base equilibria in nonpolar media. 3. Expanding the spectrophotometric acidity scale in heptane.

V. M. Vlasov, I. Leito, I. Koppel, 2003, The Journal of organic chemistry.

Anions N[C(CN)2]3- and P[C(CN)2]3- and the superacidic properties of their conjugate acids

I. Leito, I. Koppel, A. Kütt, 2007 .

Generalized principle of designing neutral superstrong Brønsted acids.

I. Leito, P. Burk, I. Koppel, 2002, Journal of the American Chemical Society.

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

I. Koppel, V. Mäemets, Vilve Nummert, 2012, Magnetic resonance in chemistry : MRC.

Gas-phase Brønsted superacidity of some derivatives of monocarba-closo-borates: a computational study.

I. Leito, I. Koppel, I. Koppel, 2009, The journal of physical chemistry. A.

Protonation of cubane in the gas phase: a high-level Ab initio and DFT study.

J. Abboud, J. Dávalos, P. Burk, 2003, Angewandte Chemie.

Acidity of anilines: calculations vs experiment.

I. Leito, P. Burk, I. Koppel, 2011, The journal of physical chemistry. A.

THEORETICAL STUDY OF DIMETHYL SULFOXIDE : ANION CLUSTERS

A. Rummel, A. Trummal, P. Burk, 1996 .

Self-consistent spectrophotometric basicity scale in acetonitrile covering the range between pyridine and DBU

I. Leito, I. Koppel, R. Schwesinger, 2000, The Journal of organic chemistry.

Effect of charged andorthosubstituents on17O NMR chemical shifts of substituted phenyl tosylates in DMSO

I. Leito, I. Koppel, T. Kesvatera, 2018, Journal of Physical Organic Chemistry.

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

I. Koppel, V. Mäemets, Vilve Nummert, 2012, Magnetic resonance in chemistry : MRC.

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

V. M. Vlasov, P. Burk, I. Koppel, 1995 .

Basicity of some P1 phosphazenes in water and in aqueous surfactant solution.

I. Leito, I. Koppel, A. Kütt, 2006, Organic & biomolecular chemistry.