1
|
Jackowski K, Wilczek M. Measurements of Nuclear Magnetic Shielding in Molecules. Molecules 2024; 29:2617. [PMID: 38893492 PMCID: PMC11173999 DOI: 10.3390/molecules29112617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/24/2024] [Accepted: 05/30/2024] [Indexed: 06/21/2024] Open
Abstract
The origin of nuclear magnetic shielding in diamagnetic molecules is discussed, pointing out various contributions to the shielding from electrons and the effects of intra- and intermolecular interactions. In NMR practice, chemical shifts are determined first as the measure of shielding in observed samples. The descriptions of shielding and chemical shifts are not fully consistent. Gas phase studies permit the withdrawal of intermolecular contributions from shielding and obtaining the magnetic shielding data in isolated molecules. The shielding determination in molecules is possible using at least three methods delivering the reference shielding standards for selected nuclei. The known shielding of one magnetic nucleus can be transferred to other nuclei if the appropriate nuclear magnetic moments are available with satisfactory accuracy. It is possible to determine the nuclear magnetic dipole moments using the most advanced ab initio shielding calculations jointly with the NMR frequencies measurements for small-sized isolated molecules. Helium-3 gas is postulated as all the molecules' primary and universal reference standard of shielding. It can be easily applied using common deuterium lock solvents as the secondary reference standards. The measurements of absolute shielding are available for everyone with the use of standard NMR spectrometers.
Collapse
Affiliation(s)
- Karol Jackowski
- Laboratory of NMR Spectroscopy, Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland;
| | | |
Collapse
|
2
|
Relativistic effects on the chemical bonding properties of the heavier elements and their compounds. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.215000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
3
|
Jackowski K, Słowiński MA. Searching for the Best Values of NMR Shielding and Spin-Spin Coupling Parameters: CH 4-nF n Series of Molecules as the Example. Molecules 2023; 28:molecules28031499. [PMID: 36771162 PMCID: PMC9919152 DOI: 10.3390/molecules28031499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 01/20/2023] [Accepted: 01/28/2023] [Indexed: 02/09/2023] Open
Abstract
Attempts at the theoretical interpretation of NMR spectra have a very long and fascinating history. Present quantum chemical calculations of shielding and indirect spin-spin couplings permit modeling NMR spectra when small, isolated molecules are studied. Similar data are also available from NMR experiments if investigations are performed in the gas phase. An interesting set of molecules is formed when a methane molecule is sequentially substituted by fluorine atoms-CH4-nFn, where n = 0, 1, 2, 3, or 4. The small molecules contain up to three magnetic nuclei, each with a one-half spin number. The spectral parameters of CH4-nFn can be easily observed in the gas phase and calculated with high accuracy using the most advanced ab initio methods of quantum chemistry. However, the presence of fluorine atoms makes the calculations of shielding and spin-spin coupling constants extremely demanding. Appropriate experimental 19F NMR parameters are good but also require some further improvements. Therefore, there is a real need for the comparison of existing NMR measurements with available state-of-the-art theoretical results for a better understanding of actual limits in the determination of the best shielding and spin-spin coupling values, and CH4-nFn molecules are used here as the exceptionally important case.
Collapse
|
4
|
Krivdin LB. Computational 1 H and 13 C NMR in structural and stereochemical studies. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:733-828. [PMID: 35182410 DOI: 10.1002/mrc.5260] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 06/14/2023]
Abstract
Present review outlines the advances and perspectives of computational 1 H and 13 C NMR applied to the stereochemical studies of inorganic, organic, and bioorganic compounds, involving in particular natural products, carbohydrates, and carbonium ions. The first part of the review briefly outlines theoretical background of the modern computational methods applied to the calculation of chemical shifts and spin-spin coupling constants at the DFT and the non-empirical levels. The second part of the review deals with the achievements of the computational 1 H and 13 C NMR in the stereochemical investigation of a variety of inorganic, organic, and bioorganic compounds, providing in an abridged form the material partly discussed by the author in a series of parent reviews. Major attention is focused herewith on the publications of the recent years, which were not reviewed elsewhere.
Collapse
Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
| |
Collapse
|
5
|
Semenov VA, Krivdin LB. Computational NMR of natural products. RUSSIAN CHEMICAL REVIEWS 2022. [DOI: 10.1070/rcr5027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
6
|
Abstract
Halogens cause pronounced and systematic effects on the 13C NMR chemical shift (δ13C) of an adjacent carbon nucleus, usually leading to a decrease in the values across the halogen series. Although this normal halogen dependence (NHD) is known in organic and inorganic compounds containing the carbon atom in its neutral and cationic forms, information about carbanions is scarce. To understand how δ13C changes in molecules with different charges, the shielding mechanisms of CHX3, CX3+, and CX3- (X = Cl, Br, or I) systems are investigated via density functional theory calculations and further analyzed by decomposition into contributions of natural localized molecular orbitals. An inverse halogen dependence (IHD) is determined for the anion series as a result of the negative spin-orbit contribution instead of scalar paramagnetic effects. The presence of a carbon nonbonding orbital in anions allows magnetic couplings that generate a deshielding effect on the nucleus and contradicts the classical association between δ13C and atomic charge.
Collapse
Affiliation(s)
- Renan V Viesser
- Institute of Chemistry, University of Campinas - UNICAMP, P.O. Box 6154, 13083-970, Campinas, São Paulo, Brazil.
| | - Cláudio F Tormena
- Institute of Chemistry, University of Campinas - UNICAMP, P.O. Box 6154, 13083-970, Campinas, São Paulo, Brazil.
| |
Collapse
|
7
|
Krivdin LB. Computational 1 H NMR: Part 1. Theoretical background. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2019; 57:897-914. [PMID: 30963636 DOI: 10.1002/mrc.4873] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 03/31/2019] [Accepted: 04/01/2019] [Indexed: 06/09/2023]
Abstract
This is the first one of the three closely interrelated reviews to be published in Magnetic Resonance in Chemistry dealing with accordingly theoretical background, chemical applications, and biochemical studies of and by means of computational 1 H NMR. Presented in the first part of the review is a general outline of the modern theoretical methods and accuracy factors of computational 1 H NMR involving locally dense basis set schemes, solvent effects, vibrational corrections, and relativistic effects performed at the density functional theory and/or nonempirical levels. This review is dedicated to Prof. Stephan Sauer in view of his invaluable contribution to the field of computational nuclear magnetic resonance.
Collapse
Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
- Angarsk State Technical University, Angarsk, Russia
| |
Collapse
|
8
|
Krivdin LB. Computational protocols for calculating 13C NMR chemical shifts. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 112-113:103-156. [PMID: 31481156 DOI: 10.1016/j.pnmrs.2019.05.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 05/19/2019] [Accepted: 05/20/2019] [Indexed: 06/10/2023]
Abstract
The most recent results dealing with the computation of 13C NMR chemical shifts in chemistry (small molecules, saturated, unsaturated and aromatic compounds, heterocycles, functional derivatives, coordination complexes, carbocations, and natural products) are reviewed, paying special attention to theoretical background and accuracy, the latter involving solvent effects, vibrational corrections, and relativistic effects.
Collapse
Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033 Irkutsk, Russia.
| |
Collapse
|
9
|
Ariai J, Saielli G. "Through-Space" Relativistic Effects on NMR Chemical Shifts of Pyridinium Halide Ionic Liquids. Chemphyschem 2019; 20:108-115. [PMID: 30312005 DOI: 10.1002/cphc.201800955] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Indexed: 12/27/2022]
Abstract
We have investigated, using two-component relativistic density functional theory (DFT) at ZORA-SO-BP86 and ZORA-SO-PBE0 level, the occurrence of relativistic effects on the 1 H, 13 C, and 15 N NMR chemical shifts of 1-methylpyridinium halides [MP][X] and 1-butyl-3-methylpyridinium trihalides [BMP][X3 ] ionic liquids (ILs) (X=Cl, Br, I) as a result of a non-covalent interaction with the heavy anions. Our results indicate a sizeable deshielding effect in ion pairs when the anion is I- and I3 - . A smaller, though nonzero, effect is observed also with bromine while chlorine based anions do not produce an appreciable relativistic shift. The chemical shift of the carbon atoms of the aromatic ring shows an inverse halogen dependence that has been rationalized based on the little C-2s orbital contribution to the σ-type interaction between the cation and anion. This is the first detailed account and systematic theoretical investigation of a relativistic heavy atom effect on the NMR chemical shifts of light atoms in the absence of covalent bonds. Our work paves the way and suggests the direction for an experimental investigation of such elusive signatures of ion pairing in ILs.
Collapse
Affiliation(s)
- Jama Ariai
- Department of Chemical Sciences University of Padova, Via Marzolo 1, 35131, Padua, Italy.,Present address: Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
| | - Giacomo Saielli
- CNR Institute on Membrane Technology, Padova Unit, Via Marzolo 1, 35131, Padua, Italy
| |
Collapse
|
10
|
Rusakov YY, Rusakova IL. Relativistic heavy atom effect on 13 C NMR chemical shifts initiated by adjacent multiple chalcogens. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:716-726. [PMID: 29412478 DOI: 10.1002/mrc.4720] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 01/21/2018] [Accepted: 01/23/2018] [Indexed: 06/08/2023]
Abstract
In this paper, we have investigated the cumulative peculiarity of the "heavy atom on light atom" effect on the 13 C NMR chemical shifts, initiated by the adjacent chalcogens. For this purpose, the most accurate hybrid computational scheme for the calculation of chemical shifts of carbon nuclei, directly bonded with several heavy chalcogens, is introduced and attested on the representative series of molecules. The best hybrid scheme combines the nonrelativistic coupled cluster-based approach with the different types of corrections, including vibrational, solvent, and relativistic. The dependences of the total relativistic corrections to carbon shielding constants in 2 series of model compounds, namely, X═13 C═Y (X, Y = O, S, Se, Te) and C(XH)m (YH)n (ZH)p (QH)s H1-m H1-n H1-p H1-s (X, Y, Z, Q = S, Se, Te and m, n, p, s = 0, 1), on the total atomic number of the adjacent chalcogens have been obtained.
Collapse
Affiliation(s)
- Yu Yu Rusakov
- A.E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033, Irkutsk, Russia
| | - I L Rusakova
- A.E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033, Irkutsk, Russia
| |
Collapse
|
11
|
Relativistic effects in the NMR spectra of compounds containing heavy chalcogens. MENDELEEV COMMUNICATIONS 2018. [DOI: 10.1016/j.mencom.2018.01.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
12
|
Samul’tsev DO, Rusakov YY, Krivdin LB. Relativistic effects of chlorine in 15N NMR chemical shifts of chlorine-containing amines. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2017. [DOI: 10.1134/s1070428017110215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
13
|
Samultsev DO, Rusakov YY, Krivdin LB. On the long-range relativistic effects in the 15 N NMR chemical shifts of halogenated azines. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2017; 55:990-995. [PMID: 28557069 DOI: 10.1002/mrc.4618] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 05/23/2017] [Accepted: 05/24/2017] [Indexed: 06/07/2023]
Abstract
Long-range β- and γ-relativistic effects of halogens in 15 N NMR chemical shifts of 20 halogenated azines (pyridines, pyrimidines, pyrazines, and 1,3,5-triazines) are shown to be unessential for fluoro-, chloro-, and bromo-derivatives (1-2 ppm in average). However, for iodocontaining compounds, β- and γ-relativistic effects are important contributors to the accuracy of the 15 N calculation. Taking into account long-range relativistic effects slightly improves the agreement of calculation with experiment. Thus, mean average errors (MAE) of 15 N NMR chemical shifts of the title compounds calculated at the non-relativistic and full 4-component relativistic levels in gas phase are accordingly 7.8 and 5.5 ppm for the range of about 150 ppm. Taking into account solvent effects within the polarizable continuum model scheme marginally improves agreement of computational results with experiment decreasing MAEs from 7.8 to 7.4 ppm and from 5.5 to 5.3 ppm at the non-relativistic and relativistic levels, respectively. The best result (MAE: 5.3 ppm) is achieved at the 4-component relativistic level using Keal and Tozer's KT3 functional used in combination with Dyall's relativistic basis set dyall.av3z with taking into account solvent effects within the polarizable continuum solvation model. The long-range relativistic effects play a major role (of up to dozen of parts per million) in 15 N NMR chemical shifts of halogenated nitrogen-containing heterocycles, which is especially crucial for iodine derivatives. This effect should apparently be taken into account for practical purposes.
Collapse
Affiliation(s)
- Dmitry O Samultsev
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, Irkutsk, 664033, Russia
| | - Yury Yu Rusakov
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, Irkutsk, 664033, Russia
| | - Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, Irkutsk, 664033, Russia
| |
Collapse
|
14
|
Fedorov SV, Rusakov YY, Krivdin LB. Quantum-chemical calculations of NMR chemical shifts of organic molecules: XV. Relativistic calculations of 29Si NMR chemical shifts of silanes. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2017. [DOI: 10.1134/s1070428017050013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
15
|
Rusakova IL, Rusakov YY, Krivdin LB. Calculation of 125Te NMR Chemical Shifts at the Full Four-Component Relativistic Level with Taking into Account Solvent and Vibrational Corrections: A Gateway to Better Agreement with Experiment. J Phys Chem A 2017; 121:4793-4803. [DOI: 10.1021/acs.jpca.7b03198] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Irina L. Rusakova
- A.E. Favorsky Irkutsk
Institute
of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033 Irkutsk, Russian Federation
| | - Yuriy Yu. Rusakov
- A.E. Favorsky Irkutsk
Institute
of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033 Irkutsk, Russian Federation
| | - Leonid B. Krivdin
- A.E. Favorsky Irkutsk
Institute
of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033 Irkutsk, Russian Federation
| |
Collapse
|