Non-covalent Interactions Laboratory

Research Topics

1. Complexes with hydrogen bond and proton transfer, spectral diagnostics of non-covalent interactions

Interpretation of molecular spectra in terms of structure and strength of non-covalent complexes is highly demanded for the investigation of “soft matter” objects (supramolecular aggregates, clusters, micelles, biopolymers), for the study of reaction rates and mechanisms, solvation processes, molecular recognition and self-assembly, for the design of new materials and molecular crystals.

2. Organometallic proton sponge derivatives and materials based on them (collaboration with Physical Organic Chemistry Department)

1,8-Bis(dimethylamino)naphthalene (DMAN) is well known under the trademark «Proton sponge» due to its abnormally high basicity for aromatic amines (pK_a = 12.1 in water). This compound is widely used in organic chemistry as low nucleophilic superbase. Our research group actively studies synthesis, structure and reactivity of organometallic derivatives of DMAN as instruments for the generation of new organic superbases and functional materials.

Publications

Selected publications 2018

V.V. Mulloyarova, I.S. Giba, M.A. Kostin, G.S. Denisov, I.G. Shenderovich, P.M. Tolstoy, “Cyclic Trimers of Phosphinic Acids in Polar Aprotic Solvent: Symmetry, Chirality and H/D Isotope Effects on NMR Chemical Shifts”, Phys. Chem. Chem. Phys. 2018, 20, 4901-4910. DOI: 10.1039/C7CP08130H.

The H-bonded self-associates of dimethylphosphinic (1), diphenylphosphoric (2), phenylphosphinic (3), bis(2,4,4-trimethylpentyl)phosphinic (4) acids have been studied by the liquid-state NMR down to 100 K in a low-freezing polar solvent CDF₃/CDClF₂. The H/D isotope effects on ¹H NMR chemical shifts unambiguously reveal the stoichiometry of the self-associates and the cooperativity of their H-bonds. In all cases, cyclic trimers are the dominant form, while cyclic dimers are present as a minor form for 1 and 2. Due to the asymmetry of substituents, cyclic trimers of 3 exist in two isomeric forms, depending on the orientation of the phenyl groups with respect to the plane of hydrogen bonds. The racemic mixture of 4 leads to the coexistence of up to 64 isomers of cyclic trimers, many of which are chemically equivalent or effectively isochronous. The complexation of 4 with SbCl₅ (complex 5) suppresses the self-association and 5 exists exclusively in the monomeric form with chemically non-equivalent ³¹P nuclei in RS, SR and RR/SS forms.

E.Yu. Tupikina, A.A. Efimova, G.S. Denisov, P.M. Tolstoy, “Outer Electronic Shell Visualization by NMR Chemical Shift Laplacian of a Helium Probe”, J. Comput. Chem. 2018, 39, 2459-2462. DOI: 10.1002/jcc.25585.

We propose a new method of visualization of lone pairs using fluorine atoms in fluoroacetylene, trifluoroethylene and fluoroform (sp, sp² and sp³ hybridized carbons) as an example. The space around fluorines was probed by a helium atom and at each point ³He NMR chemical shift δ_He and its Laplacian Ѳδ_He were calculated. The Ѳδ_He isosurfaces have symmetrical toroidal shapes along CF axes; the maximum values of Ѳδ_He are reached at ca. 1.5 Å from fluorine atom center in the direction roughly coinciding with the lone pair localization. The absolute values of the Ѳδ_He could be used to quantify the electron-rich regions of lone pairs. The results are compared with more common visualization methods – 3D maps of the molecular electrostatic potential and the electron localization function. We show that a helium atom could be used for evaluation of fine features of molecular electronic shell, since ³He NMR spectral characteristics remain sensitive at relatively large distances.

E.Yu. Tupikina, G.S. Denisov, S.M. Melikova, S.Yu. Kucherov, P.M. Tolstoy, “New look at the Badger-Bauer rule: correlations of spectroscopic IR and NMR parameters with hydrogen bond energy and geometry. FHF complexes”, J. Mol. Struct. 2018, 1164, 129-136. DOI: 10.1016/j.molstruc.2018.03.018.

The correlation dependencies between H-bond energy ∆E for complexes with F–H···F hydrogen bond and their spectroscopic characteristics of the IR and NMR spectra are presented. We considered 26 complexes in a wide hydrogen bond energy range 0.2–47 kcal/mol. For each complex we calculated complexation energy, IR spectroscopic parameters (FH stretching frequency ν, FH stretching frequency in local mode approximation ν_LM and NMR parameters (chemical shift of hydrogen δ_H and fluorine nuclei δ_F, Nuclear Independent Chemical Shielding and spin-spin coupling constants ¹J_FH, ¹J_H...F, ^2hJ_FF. We show that changes of parameters upon complexation, i.e. changes of the stretching frequency in local mode approximation ∆ν_LM, change of the proton chemical shift ∆δ_H and change of the absolute value of spin-spin coupling constant ¹J_FH could be used for estimation of corresponding hydrogen bond strength. We build correlation dependencies between abovementioned spectroscopic characteristics and geometric ones, such as the asymmetry of bridging proton position q₁ = 0.5·(r_FH – r_H…F).

A.S. Antonov, A.F. Pozharskii, P.M. Tolstoy, A. Filarowski, O.V. Khoroshilova, “1,8-Bis(dimethylamino)naphthyl-2-ketimines: Inside vs. Outside Protonation”, Beilstein J. Org. Chem. 2018, 14, 2940-2948. DOI:10.3762/bjoc.14.273.

The structure and protonation behaviour of four ortho-arylketimines of 1,8-bis(dimethylamonio)naphthalene with a different number of methoxy groups in an aromatic substituent were investigated in solution by NMR (acetone, DMSO, MeCN), in solid state by X-ray analysis and in the gas phase by DFT calculations. Both mono- and diprotonated species were considered. It has been shown that E-isomers of neutral imines can be stabilised by an intramolecular C=N−H···OMe hydrogen bond with a neighbouring methoxy group. Electron-donating OMe groups dramatically increase the basicity of the imino nitrogen, forcing the latter to abstract a proton from the proton sponge moiety in monoprotonated forms. The participation of the out-inverted and protonated 1-NMe₂ group in the Me₂N−H···NH=C hydrogen bond is experimentally demonstrated. It was shown that the number and position of OMe groups in the aromatic substituents strongly affects the rate of the internal hindered rotation of the NH₂ + fragment in dications.

A.S. Antonov, V.G. Bardakov, A.F. Pozharskii, M.A. Vovk, A.D. Misharev, “Laying the way to meta-functionalization of naphthalene proton sponge via the use of Schlosser's superbase”, J. Organomet. Chem. 2018, 855, 18–25; DOI: 10.1016/j.jorganchem.2017.12.007

Lithiation of 1,8-bis(dimethylamino)naphthalene (DMAN) with Schlosser's superbase (n-BuLi–t-BuOK) in the presence of TMEDA in hexane was examined. It has been shown that, compared with previously studied n-BuLi–TMEDA or t-BuLi–TMEDA mixtures, this reagent provides much more selective meta-lithiation. A variety of 3-substituted and 3,6-disubstituted derivatives of DMAN has been prepared in a good to reasonable yield after quenching the reaction mass with different electrophiles. A possibility of further functionalization of thus introduced meta-substituents to synthesize more complex 3-substituted derivatives of DMAN is also demonstrated.

Publications 2010–2017

1. S. Giba, V.V. Mulloyarova, P.M. Tolstoy, “Influence of POH×××N and P=O×××HC hydrogen bonds on ³¹P chemical shifts in 1:1 complexes of phosphinic acids with substituted pyridines”, J. Phys. Chem. A 2019, submitted.
2. S.N. Yunusova, D.S. Bolotin, V.V. Suslonov, M.A. Vovk, P.M. Tolstoy, V.Yu. Kukushkin, “3-Dialkylamino-1,2,4-triazoles via ZnII-catalyzed Acyl Hydrazide-Dialkylcyanamide Coupling”, ACS Omega, 2018, 3(7), 7224-7234. DOI: 10.1021/acsomega.8b01047.
3. K. Sotiriadis, P. Macova, A.S. Mazur; P.M. Tolstoy, A. Viani, “A solid state NMR and in-situ infrared spectroscopy study on the setting reaction of magnesium sodium phosphate cement”, J. Non-Cryst. Solids 2018, 498, 49-59. DOI: 10.1016/j.jnoncrysol.2018.06.006.
4. M. Shevtsov, B. Nikolaev, Y. Marchenko, L. Yakovleva, N.V. Skvorzov, A. Mazur, P. Tolstoy, V. Ryzhov, G. Multhoff, “Targeting experimental orthotopic glioblastoma with chitosan-based superparamagnetic iron oxide nanoparticles (CS-DX-SPIONs)”, Int. J. Nanomedicine 2018, 13, 1471-1482. DOI: 10.2147/IJN.S152461.
5. M. Promzeleva, T.V. Volkova, A.N. Proshin, O.I. Siluykov, A. Mazur, P.M. Tolstoy, S.P. Ivanov, F. Kamilov, I.V. Terekhova, “Improved biopharmaceutical properties of oral formulations of 1,2,4-thiadiazole derivative with cyclodextrins: in vitro and in vivo evaluation”, ACS Biomater. Sci. Eng. 2018, 4(2), 491-501. DOI: 10.1021/acsbiomaterials.7b00887.
6. E.Yu. Tupikina, M. Bodensteiner, P.M. Tolstoy, G.S. Denisov, I.G. Shenderovich, “P=O Moiety as an Ambidextrous Hydrogen Bond Acceptor”, J. Phys. Chem. C 2018, 122(3), 1711-1720. DOI: 10.1021/acs.jpcc.7b11299.
7. V.A. Rozentsvet, O.A. Stotskaya, V.P. Ivanova, M.G. Kuznetsova, P.M. Tolstoy, S.V. Kostjuk, “Structural characterization of polybutadiene synthesized via cationic mechanism”, J. Polym. Sci. A 2018, 56, 387-398. DOI: 10.1002/pola.28905.
8. E.Yu. Tupikina, A.A. Efimova, G.S. Denisov, P.M. Tolstoy, “The NMR chemical shift of a Helium atom as a probe for electronic structure of FH, F^–, (FHF)^– and FH₂⁺”, J. Phys. Chem. A 2017, 121(50), 9654-9662. DOI: 10.1021/acs.jpca.7b10189.
9. S.A. Katkova, M.A. Kinzhalov, P.M. Tolstoy, A.S. Novikov, V.P. Boyarskiy, A.Yu. Ananyan, P.V. Gushchin, M. Haukka, A.A. Zolotarev, A.Yu. Ivanov, S.S. Zlotsky, V.Y. Kukushkin, “Diversity of Isomerization Patterns and Protolytic Forms in Aminocarbene PdII and PtII Complexes Formed upon Addition of N,N'-Diphenylguanidine to Metal-activated Isocyanides”, Organometallics 2017, 36(21), 4145-4159. DOI: 10.1021/acs.organomet.7b00569.
10. S.A. Pylaeva, H. Elgabarty, D. Sebastiani, P.M. Tolstoy, “Symmetry and dynamics of FHF^– anion in vacuum, in CD₂Cl₂ and in CCl₄. Ab initio MD study of fluctuating solvent-solute hydrogen and halogen bonds”, Phys. Chem. Chem. Phys. 2017, 19, 26107-26120. DOI: 10.1039/C7CP04493C.
11. A.V. Artem’ev, I.Yu. Bagryanskaya, E.P. Doronina, P.M. Tolstoy, A.L. Gushchin, M.I. Rakhmanova, A.Yu. Ivanov, A.O. Suturina, “Facile self-assembly of new luminescent clusters containing a silver-centered tetracapped [Ag@Ag4(µ3-P)4] tetrahedron, inscribed within a N12 icosahedron”, Dalton. Trans. 2017, 46, 12425-12429, DOI: 10.1039/C7DT02597a.
12. M. Brusnikina, O. Silyukov, M. Chislov, T. Volkova, A. Proshin, A. Mazur, P. Tolstoy, I. Terekhova, «Effect of cyclodextrin complexation on solubility of novel anti-Alzheimer 1,2,4-thiadiazole derivative», J. Therm. Anal. Calorim. 2017, 130, 443-450. DOI: 10.1007/s10973-017-6252-1.
13. A.A. Osipov, V.E. Eremyashev, A.S. Mazur, P.M. Tolstoi, L.M. Osipova, «Structure of Cesium–Borosilicate Glasses According to NMR Spectroscopy», Glass Phys. Chem. 2017, 43(4), 287-293. DOI: 10.1134/S1087659617040113.
14. V.A. Rozentsvet, V.G. Kozlov, O.A. Stotskaya, N.A. Sablina, V.P. Ivanova, P.M. Tolstoy, “Kinetic parameters of cationic polymerization of 1,3-dienes”, Russ. Chem. Bulletin 2017, 66, 1088-1093. DOI: 10.1007/s11172-017-1858-9.
15. G.S. Denisov, S.F. Bureiko, S.Y. Kucherov, P.M. Tolstoy, «Correlation Relationships between the Energy and Spectroscopic Parameters of Complexes with F···HF Hydrogen Bond», Dokl. Phys. Chem. 2017, 475(1), 115-118. DOI: 10.1134/S0012501617070016.
16. N.G. Voron’ko, S.R. Derkach, M.A. Vovk, P.M. Tolstoy, «Complexation of κ-carrageenan with gelatin in the aqueous phase analyzed by 1H NMR kinetics and relaxation», Carbohydr. Polym. 2017, 169, 117-126. DOI: 10.1016/j.carbpol.2017.04.010.
17. B. Koeppe, S.A. Pylaeva, C. Allolio, D. Sebastiani, E.T.J. Nibbering, G.S. Denisov, H.-H. Limbach, P.M. Tolstoy, “Polar solvent fluctuations drive proton transfer in hydrogen bonded complexes of carboxylic acid with pyridines: NMR, IR and ab initio MD study”, Phys. Chem. Chem. Phys. 2017, 19, 1010-1028. DOI: 10.1039/C6CP06677A.
18. L. Sobczyk, D. Chudoba, P.M. Tolstoy, A. Filarowski, “Some Brief Notes on Theoretical and Experimental Investigations of Intramolecular Hydrogen Bonding”, Molecules 2016, 21, 1657-1/19. DOI:10.3390/molecules21121657.
19. A.V. Artem'ev, E.P. Doronina, M.I. Rakhmanova, A.O. Sutyrina, I.Yu. Bagryanskaya, P.M. Tolstoy, A.L. Gushchin, A.S. Mazur, N.K. Gusarova, B.A. Trofimov, “Luminescent CuI thiocyanate complexes based on tris(2-pyridyl)phosphine and its oxide: from mono-, di- and trinuclear species to coordination polymer", New J. Chem. 2016, 40, 10028-10040. DOI: 10.1039/C6NJ02087A.
20. N.G. Voron’ko, S.R. Derkach, M.A. Vovk, P.M. Tolstoy, “Formation of κ-Carrageenan–gelatin (bio)polyelectrolyte complexes studied by ¹H NMR, UV-spectroscopy and kinematic viscosity measurements”, Carbohydr. Polym. 2016, 151, 1152-1161. DOI: 10.1016/j.carbpol.2016.06.060.
21. A.A. Osipov, V.E. Eremyashev, A.S. Mazur, P.M. Tolstoi, L.M. Osipov, «Coordination State of Aluminum and Boron in Barium Aluminoborate Glass», Glass Physics and Chemistry 2016, 42(3), 230-237. DOI: 10.1134/S1087659616030111.
22. M. Sigalov, S.A. Pylaeva, P.M. Tolstoy, “Hydrogen bonding in bis-(6-amino-1,3-dimethyluracil-5-yl)-methane derivatives: dynamic NMR and DFT evaluation”, J. Phys. Chem. A 2016, 120(17), 2737-2748. DOI: 10.1021/acs.jpca.6b02184.
23. T.V. Serebryanskaya, A.S. Novikov, P.V. Gushchin, M. Haukka, R.E. Asfin, P.M. Tolstoy, V.Yu. Kukushkin, “Combined structural, theoretical and spectroscopic study of C–H···Cl− interactions of haloalkanes with chloride anion in solid state”, Phys. Chem. Chem. Phys. 2016, 18, 14104-14112. DOI: 10.1039/C6CP00861E.
24. H.-H. Limbach, G.S. Denisov, I.G. Shenderovich, P.M. Tolstoy, “Proton Tautomerism in Systems of Increasing Complexity: Examples from Organic Molecules to Enzymes” in “Tautomerism: Concepts and Applications in Science and Technology”, Edited by Liudmil Antonov, 2016, John Wiley and Sons.
25. K.I. Kulish, A.S. Novikov, P.M. Tolstoy, D.S. Bolotin, N.A. Bokach, A.A. Zolotarev, V.Yu. Kukushkin, “Solid state and dynamic solution structures of O-carbamidine amidoximes gives further insight into the mechanism of zinc(II)-mediated generation of 1,2,4-oxadiazoles”, J. Molec. Struct. 2016, 1111, 142-150. DOI: 10.1016/j.molstruc.2016.01.038.
26. A. Antonov, A. Pozharskii, V. Ozeranskii, A. Filarowski, K. Suponitsky, P. Tolstoy, “Ring Lithiation of 1,8-Bis(dimethylamino)naphthalene: Another Side of the ‘Proton Sponge Coin’”, Dalton Trans. 2015, 44, 17756-17766. DOI: 10.1039/C5DT02482J.
27. T. Kozlecki, P.M. Tolstoy, A. Kwocz, M.A. Vovk, A. Kochel, I. Polowczyka, P.Yu. Tretyakov, A. Filarowski, “Conformational state of β-hydroxynaphthylamides and barriers for the rotation of the amide group”, Spectrochimica Acta, Part A 2015, 149, 254-262. DOI: 10.1016/j.saa.2015.04.052.
28. S. Pylaeva, C. Allolio, B. Koeppe, G.S. Denisov, H.-H. Limbach, D. Sebastiani, P.M. Tolstoy, “Proton transfer in a short hydrogen bonded complex caused by solvation shell fluctuations: an ab initio MD and NMR/UV study of an (OHO)-bonded system”, Phys. Chem. Chem. Phys. 2015, 17, 4634-4644. DOI: 10.1039/c4cp04727c.
29. E.Yu. Tupikina, G.S. Denisov, P.M. Tolstoy, “NMR study of CHN hydrogen bond and proton transfer in 1,1-dinitroethane complex with 2,4,6-trimethylpyridine”, J. Phys. Chem. A. 2015, 119, 659-668. DOI: 10.1021/jp511493m.
30. I.G. Shenderovich, S.B. Lesnichin, C. Tu, D.N. Silverman, P.M. Tolstoy, G.S. Denisov, H.-H. Limbach, “NMR Studies of Active Site Properties of Human Carbonic Anhydrase II using ¹⁵N labeled 4-Methylimidazole as a Local Probe and Histidine Hydrogen Bond Correlations”, Chem. Eur. J. 2015, 21, 2915-2929. DOI: 10.1002/chem.201404083.
31. A. Miroslavov, Y. Polotskii, V. Gurzhiy, A. Ivanov, A. Lumpov, M. Tyupina, G. Sidorenko, P. Tolstoy, D. Maltsev, D. Suglobov, “Technetium and Rhenium Pentacarbonyl Complexes with C2 and C11 ω-Isocyanocarboxylic Acid Esters”, Inorg. Chem. 2014, 53, 7861-7869. DOI: 10.1021/ic500327s.
32. M. Chan-Huot, A. Dos, R. Zander, S. Sharif, P.M. Tolstoy, S. Compton, E. Fogle, M.D. Toney, I.G. Shenderovich, G.S. Denisov, H.-H. Limbach, “NMR Studies of Protonation and Hydrogen Bond States of Internal Aldimines of Pyridoxal 5’-Phosphate Acid-Base in Alanine Racemase, Aspartate Aminotransferase, and Poly-L-lysine”, J. Am. Chem. Soc. 2013, 135, 18160-18175. DOI: 10.1021/ja408988z.
33. B. Koeppe, E.T.J. Nibbering, P.M. Tolstoy, “NMR and FT-IR studies on the association of derivatives of thymidine, adenosine, and 6-N-methyl-adenosine in aprotic solvents”, Zeitschrift für Physikalische Chemie 2013, 227, 723-749. DOI: 10.1524/zpch.2013.0388.
34. Y. Rozhkova, A. A. Gurinov, P. M. Tolstoy, G. S. Denisov, I. G. Shenderovich, V. I. Korotkov, “Acridine – a Promising Fluorescence Probe of Non-Covalent Molecular Interactions”, Zeitschrift für Physikalische Chemie 2013, 227, 857-868. DOI: 10.1524/zpch.2013.0390.
35. B. Koeppe, J. Guo, P.M. Tolstoy, G.S. Denisov, H.-H. Limbach, “Solvent and H/D Isotope Effects on the Proton Transfer Pathways in Heteroconjugated Hydrogen-Bonded Phenol-Carboxylic Acid Anions Observed by Combined UV–vis and NMR Spectroscopy”, J. Am. Chem. Soc. 2013, 135, 7553-7566. DOI: 10.1021/ja400611x
36. G.A. Silantyev, O.A. Filippov, P.M. Tolstoy, N.V. Belkova, L.M. Epstein, K. Weisz, E.S. Shubina, „Hydrogen bonding and proton transfer to ruthenium hydride complex CpRuH(dppe): metal and hydride dichotomy”, Inorganic Chemistry 2013, 52, 1787-1797. DOI: 10.1021/ic301585k.
37. J. Guo, P.M. Tolstoy, B. Koeppe, N.S. Golubev, G.S. Denisov, S.N. Smirnov, H.-H. Limbach, “Hydrogen Bond Geometries and Proton Tautomerism of Homo-Conjugated Anions of Carboxylic Acids Studied via H/D Isotope Effects on ¹³C NMR Chemical Shifts”, J. Phys. Chem. A 2012, 116, 11180-11188. DOI: 10.1021/jp304943h
38. B.C.K. Ip, I.G. Shenderovich, P.M. Tolstoy, J. Frydel, G.S. Denisov, G. Buntkowsky, H.-H. Limbach, “NMR Studies of H/D Isotope and Phase Effects on 4-Methylpyridine-Pentachlorophenol Complexes and Implications for the Shapes of Hydrogen-bonded Protons in the Solid and the Liquid State”, J. Phys. Chem. A 2012, 116, 11370-11387. DOI: 10.1021/jp305863n
39. N.Yu. Gorobets, S.A. Yermolayev, T. Gurley, A.A. Gurinov, P.M. Tolstoy, I.G. Shenderovich, N.E. Leadbeater, “Difference between ¹H NMR signals of primary amide protons as a simple spectral index of the amide intramolecular hydrogen bond strengths”, J. Phys. Org. Chem., 2012, 25, 287-295.
40. H.-H. Limbach, M. Chan-Huot, S. Sharif, P.M. Tolstoy, I.G. Shenderovich, G.S. Denisov, M.D. Toney, “Critical hydrogen bonds and protonation states of pyridoxal 5’-phosphate revealed by NMR”, Biochimica Biophysica Acta Proteins and Proteomics, 2011, 1814, 1426-1437.
41. J. Guo, P.M. Tolstoy, B. Koeppe, G.S. Denisov, H.-H. Limbach, “NMR Study of Conformational Exchange and Geometries of Intramolecular Hydrogen Bonds in Monoanions of Succinic Acid and Derivatives”, J. Phys. Chem. A, 2011, 115, 9828-9836. DOI: 10.1021/jp201073j.
42. B. Koeppe, P.M. Tolstoy, H.-H. Limbach, “Reaction Pathways of Proton Transfer in Hydrogen bonded Phenol-Carboxylate Complexes explored by UVNMR”, J. Am. Chem. Soc., 2011, 133, 7897-7908.
43. B. Koeppe, P.M. Tolstoy, E.T. J. Nibbering, T. Elsaesser, “Two-dimensional UV-vis/NMR Correlational Spectroscopy: A Heterospectral Signal Assignment of Hydrogen-Bonded Complexes”, J. Phys. Chem. Lett., 2011, 2, 1106-1110.
44. J. Guo, B. Koeppe, P.M. Tolstoy, “Trimethylglycine Complexes with Carboxylic Acids and HF: Solvation by Polar Aprotic Solvent”, PCCP, 2011, 13, 2335-2341. DOI: 10.1039/C0CP01659D
45. D. Ajami, P.M. Tolstoy, H. Dube, S. Odermatt, B. Koeppe, J. Guo, H.-H. Limbach, J. Rebek Jr., “Compressed Hydrogen Bonds Isolated in Encapsulation Complexes”, Angew. Chem. Int. Ed. 2011, 50, 528-531. DOI: 10.1002/anie.201002182
46. M. Chan-Huot, S. Sharif, P.M. Tolstoy, M.D. Toney, H.-H. Limbach, “NMR Studies of the Stability, Protonation States and Tautomerism of ¹³C and ¹⁵N Labeled Aldimines of the Coenzyme Pyridoxal 5’-phosphate in Water”, Biochemistry, 2010, 49, 10818-10830. DOI: 10.1021/bi101061m.
47. P.M. Tolstoy, J. Guo, B. Koeppe, N.S. Golubev, G.S. Denisov, S.N. Smirnov, H.-H. Limbach, “Geometries and Tautomerism of OHN Hydrogen Bonds in Aprotic Solution Probed by H/D Isotope Effects on ¹³C NMR Chemical Shifts”, J. Phys. Chem. A 2010, 114, 10775-10782. DOI: 10.1021/jp1027146.
48. S.B. Lesnichin, P.M. Tolstoy, H.H. Limbach, I.G. Shenderovich, “Counteranion-dependent mechanisms of intramolecular proton transfer in aprotic solution”, Phys. Chem. Chem. Phys., 2010, 12, 10373-10379.
49. L. Szyc, J. Guo, M. Yang, J. Dreyer, P.M. Tolstoy, E.T.J. Nibbering, B. Czarnik-Matusewicz, T. Elsaesser, H.-H. Limbach, “The Hydrogen-Bonded 2-Pyridone Dimer Model System. I. Combined NMR and FT-IR Study”, J. Phys. Chem. A 2010, 114, 7749-7760.
50. M. Chan-Huot, C. Niether, S. Sharif, P. M. Tolstoy, M. D. Toney, H.-H. Limbach “NMR Studies of the Protonation States of Pyridoxal 5’-phosphate in Water”, J. Mol. Struct. 2010, 976, 282-289.
51. M. Pietrzak, J.P. Wehling, S. Kong, P.M. Tolstoy, I.G. Shenderovich, C. Lopez, R.M. Claramunt, J. Elguero, G.S. Denisov, H.-H. Limbach, “Symmetrization of Cationic Hydrogen Bridges of Protonated Sponges Induced by Solvent and Counteranion Interactions as Revealed by NMR Spectroscopy”, Chem. Eur. J., 2010, 16, 1679-1690.

Research Projects

Diagnostics of complexes with hydrogen and halogen bonds using ³¹P NMR spectroscopy

We work on establishing predictive correlational dependencies for the interpretations of ³¹P NMR chemical shifts in terms of strength and geometry of hydrogen and halogen bonds formed by phosphinic acids R₂POOH and phosphine oxides R₃PO (JPCC 2018, 122, 1711). Constructing such correlations is complicated by the fact that d³¹P responds sensitively to a large number of secondary factors. For example, for POOH acids d³¹P values depend on internal degrees of freedom of substituents R and on the formation of additional hydrogen bonds with oxygen atoms. Nevertheless, in some cases it is possible to observe fine correlations with the proton transfer coordinate in POOH•••X hydrogen bond.

Probing of electron shells by Helium atom ³He

We proposed a new method of quantum-chemical diagnostics of outer electron shells of proton-accepting atoms (f.e. fluorine) using 3D mapping by a Helium atom ³He. We show that the position of maxima in ³He NMR chemical shift Laplacian maps points to the localization regions of fluorine lone pairs (i.e. to the regions of its maximal proton accepting ability), while the value of this Laplacian at the maximum is proportional to the degree of lone pair localization (JCC 2018, 39, 2459). Thus, it might be said that ³He NMR chemical shift Laplacian maps combine certain advantages of electron localization function (ELF) and molecular electrostatic potential (MESP).

Building spectrum-structure correlations for hydrogen- and halogen-bonded complexes

Using quantum-chemical calculations for model systems and experimental spectroscopy for homologous series of hydrogen- and halogen-bonded complexes we build correlations linking spectral observables (chemical shifts, coupling constants, vibrational frequencies) with geometric and energetic characteristics of complexes. Such correlations might be further used to determine interatomic distance and complexation energies using experimental NMR and IR spectra. See, for example, J. Mol. Struct. 2018, 1164, 129; Dokl. Phys. Chem. 2017, 475, 115; JPCA 2015, 119, 659.

Low-temperature NMR in liquefied Freon gases

We develop applications of low-temperature NMR spectroscopy in solutions in mixtures of deuterated liquefied gases CDF₃/CDF₂Cl. Low temperature and low viscosity of this solvent allows one to obtain high-resolution liquid-state NMR spectra at temperatures as low as 100 K. At this temperature processes of molecular and proton exchange slow down and the signals of complexes with different stoichiometry, structure and isotopic composition become revolved in NMR spectra (see, f.e., JPCA 2012, 116, 11180; 2011, 115, 9828 or PCCP 2011, 13, 2335).

Combined NMR/UV-Vis spectroscopy

We have constructed a new experimental setup for the simultaneous and synchronous registration of NMR and UV-vis spectra within the magnet of NMR spectrometer (Angew. Chem. 2009, 48, 5745). Using this setup and 2D correlational NMR-UV spectroscopy we have managed to determine the structure and spectra of a number of phenol-carboxylate complexes (JPCL 2011, 2, 1106; JACS 2013, 135, 7553).

The chemistry of proton sponge’s organometallic derivatives

Although lithium derivatives of 1,8-bis(dimethylamino)naphthalene have been long used to generate new proton sponges, the specifics of formation, structure, and reactivity of these organometallics remain poorly understood. At the same time, DMAN derivatives with other metals are not known at all. In order to fill this gap in the chemistry of these superbases, the following projects are being implemented in our laboratory:

• Investigation of the direct lithiation of 1,8-bis(dimethylamino)naphthalene in order to synthesize its hard-to-reach meta- and peri-derivatives.
• Investigation of the structure and aggregation behavior of DMAN’s lithium derivatives by low-temperature liquid state NMR spectroscopy.
• Synthesis and reactivity of copper and boron derivatives 1,8-bis(dimethylamino)naphthalene.

Novel polymeric materials based on proton sponges

Today, special attention is paid to the development of functional materials, in particular polymers with the properties of superbases. Keeping in mind the unique basicity of the proton sponges, these compounds appear especially promising for research in this field. In this area, our laboratory implements the following projects:

• Superbasic polymeric materials with different kinetic basicity — polymeric catalysts and proton-conducting polymers.
• Hydride sponges based materials for hydrogen storage.