Influence of the C—H· · ·N intramolecular interaction on the spatial structures and <sup>1</sup>H and <sup>13</sup>C NMR parameters of heteroaryl vinyl ethers and sulfides

Afonin, A. V.; Ushakov, Igor А.; Kuznetsova, S. Yu.; Andriyankova, L. V.

doi:10.1002/mrc.1215

Cited by 14 publications

(5 citation statements)

References 30 publications

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“…Presumably, exclusively electrostatic nature of the CH···N hydrogen bond [15][16][17][18][19] makes such interactions nonsaturable, i.e., both bifurcated and ordinary hydrogen bridges of that type are characterized by similar strengths.…”

mentioning

confidence: 98%

1H and 13C NMR Study of Bifurcated Intramolecular Hydrogen Bonds in 2,6-Bis(2-pyrrolyl)pyridine and 2,6-Bis(1-vinyl-2-pyrrolyl)pyridine

et al. 2005

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According to the 1 H and 13 C NMR data, bifurcated intramolecular hydrogen bond NH···N··· HN in 2,6-bis(2-pyrrolyl)pyridine fixes its molecule in a conformation with syn orientation of the pyrrole rings. An analogous bifurcated hydrogen bond CH · · · N · · · HC is formed in 2,6-bis(1-vinyl-2-pyrrolyl)pyridine. 2-(1-Vinyl-2-pyrrolyl)-6-(2-pyrrolyl)pyridine is characterized by unsymmetrical bifurcated hydrogen bond NH···N···HC.Systematic studies on the 1 H and 13 C NMR spectra of a wide series of pyrrole derivatives [1-7] allowed us to distinguish 2-hetarylpyrroles as a class of compounds giving rise to various intramolecular hydrogen bonds. For example, a weak intramolecular hydrogen bond CH · · · N between the -hydrogen atom of the vinyl group and pyridine nitrogen atom was found in 1-vinyl-2-(2-pyridyl)pyrrole [6]. 2-(2-Pyridyl)pyrrole is characterized by a weak intramolecular hydrogen bond NH···N between the pyrrole N-H atom and pyridine nitrogen atom [4]. The 1 H NMR and IR spectra of 5-(2-pyridyl)-2-trifluoroacetylpyrrole revealed a bifurcated hydrogen bond involving both pyridine nitrogen atom and carbonyl oxygen atom of the trifluoroacetyl group [4,5]. In continuation of our studies on intramolecular hydrogen bonds in pyrrole derivatives, in the present work we examined the 1 H and 13 C NMR spectra of 2,6-bis(2-pyrrolyl)pyridine (I) and 2,6-bis-(1-vinyl-2-pyrrolyl)pyridine (VI) and compared the results with those found for model compounds II-V and VII-XIV.The 1 H and 13 C NMR spectra of pyrroles I-XIV are given in Tables 1 and 2, and the 13 C-1 H coupling constants are collected in Table 3. Following the previously used algorithm for studying 2-hetarylpyrroles by NMR spectroscopy, let us consider first the character of , conjugation between the heterorings in compounds I and VI on the basis of the corresponding carbon chemical shifts. We showed in [4] that the signals from C 3' and C 5' in the pyridine ring of I-V, R 1 = H; I, R 2 = H; II, R 2 = 2-pyridyl; III, R 2 = 3-pyridyl; IV, R 2 = 4-pyridyl; V, R 2 = Ph; VI-XIII, R 1 = CH 2 =CH; VI, VII, R 2 = CH 2 =CH; VIII, R 2 = 2-pyridyl; IX, R 2 = 3-pyridyl; X, R 2 = 4-pyridyl; XI, R 2 = Ph; XII, XIII, R 2 = H. 3'2'

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mentioning

confidence: 98%

1H and 13C NMR Study of Bifurcated Intramolecular Hydrogen Bonds in 2,6-Bis(2-pyrrolyl)pyridine and 2,6-Bis(1-vinyl-2-pyrrolyl)pyridine

et al. 2005

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“…As discussed earlier, the intrinsic low sensitivity of 2D INADEQUATE and the sometimes poor solubility of heterocyclic compounds often impede an efficient use of this method for structure assignments and only a limited number of examples is known in the literature where 1D or 2D INADEQUATE have been utilized for the confirmation of proposed heterocyclic structures . However, we believe that our study illustrates that even rather simple molecules feature a great margin for erroneous structure assignments if they are only based on standard correlation techniques such as HMBC.…”

Section: Resultsmentioning

confidence: 73%

Unambiguous structure elucidation of heterocyclic products from condensation–cyclisation reactions of enaminones by 2D INADEQUATE and ¹⁵N NMR

Liermann

Elnagdi

Meier

2012

Magnetic Reson in Chemistry

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“…2 ppm downfield shifted. Such deshielding is in accordance with an intramolecular C–H···S interaction . Note that this interaction would not be present if the insertion of the {SCN} group took place with the opposite regiochemistry (isomer B ).…”

Section: Resultsmentioning

confidence: 85%

“…Such deshielding is in accordance with an intramolecular C–H···S interaction. 25 Note that this interaction would not be present if the insertion of the {SCN} group took place with the opposite regiochemistry (isomer B ). Similar patterns are noticed for the 13 C{ 1 H} NMR data: a generalized shielding of the η 6 -arene and N , N -heterocyclic resonances accompanies the transformation of [ 1a – e ] + into 2a – e , except for the C–H group discussed above (p4) and the quaternary pyridyl carbon (p5).…”

Section: Resultsmentioning

confidence: 99%

Triazine Chalcogenones from Thiocyanate or Selenocyanate Addition to Tetrazine Ligands in Ruthenium Arene Complexes

Bonaldi,

Bortoluzzi,

Zacchini

et al. 2023

Inorg. Chem.

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The chemistry of 1,2,4,5-tetrazines has attracted considerable interest both from a synthetic and applicative standpoint. Recently, regioselective reactions with alkynes and alkenes have been reported to be favored once the tetrazine ring is coordinated to Re(I), Ru(II), and Ir(III) centers. Aiming to further explore the effects of metal coordination, herein, we unveil the unexplored reactivity of tetrazines with chalcogenocyanate anions. Thus, ruthenium(II) tetrazine complexes, [RuCl{κ2 N-3-(2-pyridyl)-6-R-1,2,4,5-tetrazine}(η6-arene)]+ (arene = p-cymene, R = H, [1a]+, R = Me, [1b]+, R = 2-pyridyl, [1c]+; arene = C6Me6, R = H, [1d]+, R = Me, [1e]+; PF6 – salts), reacted quantitatively and in mild conditions with M(ECN) salts (M = Na, K, Bu4N; E = O, S, Se). The addition of thiocyanate or selenocyanate to the tetrazine ligand is regioselective and afforded, via N2 release, 1,2,4-triazine-5-chalcogenone heterocycles, the one with selenium being unprecedented. The novel ruthenium complexes [RuCl{κ2 N-(2-pyridyl)}{triazine chalcogenone}(η6-arene)] 2a–e (sulfur), 3b, 3d, and 3e (selenium) were characterized by analytical (CHNS analyses, conductivity), spectroscopic (IR, multinuclear and two-dimensional (2D) NMR), and spectrometric (electrospray ionization mass spectrometry (ESI-MS)) techniques. According to density functional theory (DFT) calculations, the nucleophilic attack of SCN– on the tetrazine ring is kinetically driven. Compound 2b is selectively and reversibly mono-protonated on the triazine ring by HCl or other strong acids, affording a single tautomer. When reactions of chalcogenocyanates were performed on the 2,2′-bipyridine (bpy) complex [RuCl(bpy)(η6-p-cymene)]+, the chloride substitution products [Ru(ECN)(bpy)(η6-p-cymene)]+ (E = O, [4]+; E = S, [5]+; E = Se, [6]+) were obtained in 82–90% yields (PF6 – salts). Combined spectroscopic data (IR, 1H/13C/77Se NMR) was revealed to be a useful tool to study the linkage isomerism of the chalcogenocyanate ligand in [4–6]+.

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Influence of the C—H· · ·N intramolecular interaction on the spatial structures and ¹H and ¹³C NMR parameters of heteroaryl vinyl ethers and sulfides

Cited by 14 publications

References 30 publications

1H and 13C NMR Study of Bifurcated Intramolecular Hydrogen Bonds in 2,6-Bis(2-pyrrolyl)pyridine and 2,6-Bis(1-vinyl-2-pyrrolyl)pyridine

1H and 13C NMR Study of Bifurcated Intramolecular Hydrogen Bonds in 2,6-Bis(2-pyrrolyl)pyridine and 2,6-Bis(1-vinyl-2-pyrrolyl)pyridine

Unambiguous structure elucidation of heterocyclic products from condensation–cyclisation reactions of enaminones by 2D INADEQUATE and ¹⁵N NMR

Triazine Chalcogenones from Thiocyanate or Selenocyanate Addition to Tetrazine Ligands in Ruthenium Arene Complexes

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Influence of the C—H· · ·N intramolecular interaction on the spatial structures and 1H and 13C NMR parameters of heteroaryl vinyl ethers and sulfides

Cited by 14 publications

References 30 publications

1H and 13C NMR Study of Bifurcated Intramolecular Hydrogen Bonds in 2,6-Bis(2-pyrrolyl)pyridine and 2,6-Bis(1-vinyl-2-pyrrolyl)pyridine

1H and 13C NMR Study of Bifurcated Intramolecular Hydrogen Bonds in 2,6-Bis(2-pyrrolyl)pyridine and 2,6-Bis(1-vinyl-2-pyrrolyl)pyridine

Unambiguous structure elucidation of heterocyclic products from condensation–cyclisation reactions of enaminones by 2D INADEQUATE and 15N NMR

Triazine Chalcogenones from Thiocyanate or Selenocyanate Addition to Tetrazine Ligands in Ruthenium Arene Complexes

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Influence of the C—H· · ·N intramolecular interaction on the spatial structures and ¹H and ¹³C NMR parameters of heteroaryl vinyl ethers and sulfides

Unambiguous structure elucidation of heterocyclic products from condensation–cyclisation reactions of enaminones by 2D INADEQUATE and ¹⁵N NMR