Tuning the hydrogen-bonding strength in 2,6-bis(cycloalkylcarbonylamino)pyridine assemblies by variable flexibility. Association constants measured by hydrogen-bonded vs. non-hydrogen-bonded protons

Ośmiałowski, Borys; Kolehmainen, Erkki; Kauppinen, Reijo; Kowalska, Magdalena

doi:10.1080/10610278.2011.575470

Cited by 11 publications

(24 citation statements)

References 61 publications

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“…An increased flexibility of the 2-acylamino substituent in pyrimidine is argued to be due to electron lone pair repulsions between N-3 and carbonyl oxygen [16]. This was confirmed by comparison of the heteroassociation of 2,2 0 -dipyridylamine versus 2-acetylaminopyrimidine which both contain ADA hydrogen bond motifs with DAD counterparts capable for triple hydrogen bonding [12]. The weak (usually below 16 kJ/mol [21,22]) CHÁÁÁO [23][24][25], CHÁÁÁN [26,27], or CHÁÁÁp [28] interactions may also influence the geometry [29] of self-assembled molecules.…”

Section: Introductionsupporting

confidence: 53%

“…The dimerization constants (K dim ) . at 293 K are 1.4 for 1 and 1.7 M -1 for 2, respectively, when both NH and CH protons were used as probe nuclei [12].…”

Section: As Implemented In Gaussian [49] With Default Settings (See Lmentioning

confidence: 99%

“…It has been shown how hydrogen bonding can be used in designing the shape of aggregate [5][6][7] in solution and in solid state [8]. Generally, non-covalent intermolecular interactions are influenced by steric effects [9][10][11][12], electronic repulsion [11,13], position of the heteroatoms in the ring [14][15][16], and cooperative effects [17]. The atoms able to compete for hydrogen bonds (basic or acidic centers) are responsible for the conformational flexibility of NH-CO bond in amides [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

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The influence of CH bond polarization on the self-association of 2-acylaminopyrimidines by NH/CH···O/N interactions: XRD, NMR, DFT, and AIM study

et al. 2013

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The single crystal structures of two 2-acylaminopyrimidines, where alkyl groups in acyl moiety are iso-propyl (1) and dichloromethyl (2), were solved by X-ray diffraction method. The strength of intermolecular hydrogen bonding interactions depends on the C-H bond polarization increased by exchanging two methyl groups by chlorine atoms in the adjacent substituent. The computational methods provide an additional insight into the intermolecular interactions and are utilized in explaining the differences in the observed crystal structures. The experimental and computational data together explain the differences in the formed aggregates and revealed that these simple substitutions cause crucial changes in the intermolecular interactions.

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Section: Introductionsupporting

confidence: 53%

“…The dimerization constants (K dim ) . at 293 K are 1.4 for 1 and 1.7 M -1 for 2, respectively, when both NH and CH protons were used as probe nuclei [12].…”

Section: As Implemented In Gaussian [49] With Default Settings (See Lmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The influence of CH bond polarization on the self-association of 2-acylaminopyrimidines by NH/CH···O/N interactions: XRD, NMR, DFT, and AIM study

et al. 2013

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“…The association constants ( K assoc ) are collected in Table 1 (see Supporting Information File 1 for figures). Usually the NH/OH protons are used to find K assoc but in some cases CH chemical shifts are also useful [ 9 , 52 ]. Here the protons of methylene attached directly to nitrogen atom were observed during the experiments ( Supporting Information File 1 , Figure S13).…”

Section: Resultsmentioning

confidence: 99%

Conformational equilibrium in supramolecular chemistry: Dibutyltriuret case

Mroczyńska¹,

Kaczorowska²,

Kolehmainen³

et al. 2015

Beilstein J. Org. Chem.

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SummaryThe association of substituted benzoates and naphthyridine dianions was used to study the complexation of dibutyltriuret. The title molecule is the simplest molecule able to form two intramolecular hydrogen bonds. The naphthyridine salt was used to break two intramolecular hydrogen bonds at a time while with the use of substituted benzoates the systematic approach to study association was achieved. Both, titrations and variable temperature measurements shed the light on the importance of conformational equilibrium and its influence on association in solution. Moreover, the associates were observed by mass spectrometry. The DFT-based computations for complexes and single bond rotational barriers supports experimental data and helps understanding the properties of multiply hydrogen bonded complexes.

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“…The stability of hydrogen-bonded complexes depends on many factors such as the strength and the number of intermolecular hydrogen bonds, the character of the hydrogen bond donor (D) and acceptor (A), secondary interactions (SIs, as introduced by Jorgensen and Pranata), steric effects, − and competition with solvent molecules. Recently we have demonstrated that even the relatively small methyl group is able to influence interactions in the solution and to determine the crystal structure .…”

Section: Introductionmentioning

confidence: 99%

Association ofN-(Pyridin-2-yl),N′-substituted Ureas with 2-Amino-1,8-naphthyridines and Benzoates: NMR and Quantum Chemical Studies of the Substituent Effect on Complexation

et al. 2013

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Association of four N-(pyridin-2-yl),N'-R(1)-ureas (R(1) = ethyl, n-butyl, phenyl, and tert-butyl) with substituted 2-amino-1,8-naphthyridines and benzoates were studied by (1)H NMR spectroscopic titrations and quantum chemical calculations. The benzoates and 2-amino-1,8-naphthyridines were selected as representatives of double and triple hydrogen bonding counterparts, respectively. The classical substituent effect on the association was studied. A prerequisite and a crucial step for the complex formation was the breaking of the intramolecular hydrogen bond in urea derivatives. The QTAIM calculation method was employed to explain the hydrogen bonding within complexes. In the case of benzoates carrying an electron-donating substituent the experimental findings were explained by the formation of two complexes. These observations were rationalized by the electronic repulsions between atoms in a close proximity and further verified by calculations. Single-crystal X-ray diffraction was used to confirm the structure of studied ureas in the crystalline state. These results are in line with the solution studies of self-association of ureas.

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Tuning the hydrogen-bonding strength in 2,6-bis(cycloalkylcarbonylamino)pyridine assemblies by variable flexibility. Association constants measured by hydrogen-bonded vs. non-hydrogen-bonded protons

Cited by 11 publications

References 61 publications

The influence of CH bond polarization on the self-association of 2-acylaminopyrimidines by NH/CH···O/N interactions: XRD, NMR, DFT, and AIM study

The influence of CH bond polarization on the self-association of 2-acylaminopyrimidines by NH/CH···O/N interactions: XRD, NMR, DFT, and AIM study

Conformational equilibrium in supramolecular chemistry: Dibutyltriuret case

Association ofN-(Pyridin-2-yl),N′-substituted Ureas with 2-Amino-1,8-naphthyridines and Benzoates: NMR and Quantum Chemical Studies of the Substituent Effect on Complexation

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