<scp>NMR</scp>Spectra of Anilines

Kolehmainen, Erkki; Gawinecki, Ryszard; Ośmiałowski, Borys

doi:10.1002/9780470682531.pat0388

Cited by 4 publications

(7 citation statements)

References 106 publications

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“…In the spectra of the nonpurified DUT-92(NH 2 ), a shift of −331 ppm indicates the complete protonation of the amino groups, yielding ammonium groups. After Soxhlet extraction, the signal becomes much broader and is split into two signals, at −324 ppm, corresponding now to an amine group, and at −330 ppm, corresponding to the remaining ammonium groups . The broader line width might be a hint for a higher number of possible conformations of the amino group and thus a higher flexibility.…”

Section: Resultsmentioning

confidence: 99%

Tailoring Pore Structure and Properties of Functionalized Porous Polymers by Cyclotrimerization

Wisser¹,

Eckhardt²,

Wisser³

et al. 2014

Macromolecules

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Porous polymers were prepared by cyclotrimerization reaction in molten p-toluenesulfonic acid. Their properties could be tailored by functionalization of the aromatic diacetyl monomers. Thus, a range of homo-and copolymers based on hydrogen-, amine-, or nitro-functionalized 4,4′-diacetylbiphenyl derivatives and 1,4-diacetylbenzene was synthesized. The pores size could be tuned from mainly microporous to hierarchical micro-and mesoporous or even hierarchical micro-and macroporous. BET surface areas up to 720 m 2 /g and total pore volumes up to 1.76 cm 3 /g were achieved. The formation of different pore types was related to the solvent−monomer/polymer interactions, which is shown by 15 N solid state MAS NMR spectroscopy and SEM. Other physical properties such as surface polarity and thermal stability were influenced by the different monomers as well.

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Section: Resultsmentioning

confidence: 99%

Tailoring Pore Structure and Properties of Functionalized Porous Polymers by Cyclotrimerization

Wisser¹,

Eckhardt²,

Wisser³

et al. 2014

Macromolecules

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“…Several excellent review articles and book chapters have been devoted to general nitrogen NMR spectroscopy [1][2][3][4][5][6][7][8][9][10][11][12][13], long-range 1 H-15 N shift correlations [14,15], and various classes of compounds, e.g., purines [16], anilines [17], metal nitrosyls [18], and many others.…”

Section: Why the 15 N Nucleus?mentioning

confidence: 99%

“…The 15 N chemical shift of substituted anilines (see Table 2) can be used as a probe for investigating the influence of the substituents and the degree of delocalization of the nitrogen lone pair [17]. The surprisingly weak sensitivity of the 15 N chemical shift of the nitro group upon substitution in substituted nitrobenzenes (see Table 2) has been clarified recently by solid-state 15 N NMR experiments and theoretical calculations [29].…”

Section: N Chemical Shiftsmentioning

confidence: 99%

15N NMR Spectroscopy in Structural Analysis: An Update (2001 - 2005)

Marek¹,

Lyčka²,

Kolehmainen³

et al. 2007

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Since our previous review article (Curr. Org. Chem. 2002, 6, 35), significant improvements and an array of 15 N NMR applications in structural analysis have been published. This report aims to update coverage of improvements in methodology and various types of applications published over the period 2001 -2005. Substantial progress in cryogenic probe technology and the commercial availability of cryoprobes have facilitated the measurement of 15 N NMR parameters.The number of solid-state applications has increased significantly during the past few years. In contrast to our previous review, this article covers 15 N solid-state studies. The 15 N NMR chemical shifts of organic molecules are routinely measured by using cross-polarization magic-angle spinning (CP/MAS) techniques. The principal values of the chemical shift tensors can also be determined. 1 H-15 N and 2 H-15 N distance measurements made by means of 1 H detection are currently used in NMR crystallography.User friendly quantum chemical programs allow for the routine calculation of 15 N chemical shielding and indirect spinspin coupling constants, especially using density functional theory (DFT).Applications of 15 N NMR spectroscopy in various fields of chemistry are summarized here. Major sections represent tautomerism, complexation, protonation, and hydrogen bonding. The other topics comprise N-alkylation, N-oxidation, regioisomerism, and changes in configuration or conformation.

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“…The R values for the methine carbon atom and for quaternary CO are 0.93 and 0.83, respectively. Moreover, because the nitrogen atom is very sensitive to the change in its environment, , the 15 N chemical shift was used for analysis as it is related to the resonance substituent constant with an R of 0.94 [δ( 15 N) = 7.17σ – 171.75, and Δδ( 15 N) = 2.78]. The values of the slope of the fitted function for methine and CO carbon atoms are 5.17 and −2.11, respectively, and taking into account the range of changes in 13 C and 15 N shifts [methine Δδ( 13 C) = 2.13 ppm, and CO Δδ( 13 C) = 0.87 ppm] shows that, indeed, the 15 N chemical shifts are more sensitive than their 13 C counterparts to the substituent effect.…”

Section: Resultsmentioning

confidence: 99%

“…Of course, the DA interaction (that is the charge transfer) is, in general, already present, at least partially, in the ground state in solid as well as in solution depending on the character of the donor and acceptor groups . The amplitude of the electron density shift appearing in the ground state is dependent on the geometry of the amino group, as demonstrated by nuclear magnetic resonance (NMR) studies performed on a series of anilines carrying amino groups with various geometrical orientations . This allowed the calculation of substituent constants for various amino groups that have been used in a number of studies, e.g., to investigate the photoisomerisation of push–pull chromophores .…”

Section: Introductionmentioning

confidence: 99%

Influence of the Nature of the Amino Group in Highly Fluorescent Difluoroborates Exhibiting Intramolecular Charge Transfer

et al. 2018

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A series of difluoroborates were synthesized from CH acids. All compounds were substituted with dialkylamino groups (NR). The lone electron pair of the nitrogen atom of this donor moiety is variably delocalized toward the difluoroborate core that acts as the electron acceptor. This was rationalized in light of the various geometries of the amino group. The degree of charge transfer was quantified on the basis of the results of time-dependent density functional theory calculations.

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NMRSpectra of Anilines

Abstract: Introduction Ring and N ‐Substituted Anilines Multinuclear NMR Studies of p ‐ F ‐Aniline Derivatives Dynamic NMR of Aniline Derivatives … Show more

Cited by 4 publications

References 106 publications

Tailoring Pore Structure and Properties of Functionalized Porous Polymers by Cyclotrimerization

Tailoring Pore Structure and Properties of Functionalized Porous Polymers by Cyclotrimerization

15N NMR Spectroscopy in Structural Analysis: An Update (2001 - 2005)

Influence of the Nature of the Amino Group in Highly Fluorescent Difluoroborates Exhibiting Intramolecular Charge Transfer

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