Self-complexation of macrocyclic polyethers studied by carbon-13 NMR longitudinal relaxation time measurements and molecular mechanics

Grootenhuis, Peter D. J.; Eerden, J. Van; Sudhoelter, E. J. R.; Reinhoudt, David N.; Roos, A.; Harkema, Sybolt; Feil, D.

doi:10.1021/ja00250a006

Cited by 29 publications

(6 citation statements)

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“…However, we are now faced with the need to improve the analytical methods for the measurement of association constants (Table 1) [8,9]. The results were consistent with those reported elsewhere [3][4][5][7][8][9][10]. The association constants of [3n]crown-n, benzo[3n]crown-n, cyc1ohexano[18]-crown-6, 2,6-dioxo[18]crown-6, and 2,6-dioxo-[15] crown-5 derivatives that complex with Li\ Na+, K+ and Ca 2 + cations were studied in polar solvents.…”

Section: Resultssupporting

confidence: 83%

“…Macrocycles ranging from podands and coronands to cyriptates and calixarenes have been studied in this way. In particular, the eHlYC NMR method is reliable if it is conducted at various temperatures together with NOE factor measurements [4,5,[7][8][9]. Cation quadrupolar relaxation rate studies have opened a new field that has provided information with which to test earlier theories and has led to new concepts on bio-chemical receptors [2].…”

Section: Introductionmentioning

confidence: 99%

“…Similarly, studies on podands have revealed the sensitivity of the method, even in the case of weak cation interactions [3]. The effect of cation binding is usually a decrease in the relaxation time that depends on the selectivity and the stability of the receptor [4,8,9]. a complex is coupled to structural complementarity between complexed sides, which has been studied by intramolecular relaxation rate, (l/T1)intra measurements.…”

Section: Introductionmentioning

confidence: 99%

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Cation Complexation and Stereochemistry of Macrocycles Studied by 13C NMR Relaxation-Time Measurements

Erk

1999

NMR in Supramolecular Chemistry

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Cation binding by macrocycles was studied using l3C NMR dipole-dipole relaxation measurements in solution. The association constants of [3n]Crown-n and its cyclohexyl, benzo and dioxo derivatives with Li+, Na+, K+ and Ca 2 + cations were studied in polar solvents. The relaxation times, T 1 0bS and NOE factors (11) of 13C atoms in the backbone of free and complex macrocycles were estimated in the extreme narrowing NMR conditions and gave TODD and TIODD dipolar relaxation times. The internal motions coupled with the dipolar relaxation times are influenced by cation binding characterized by the association constants, Ka. The experimental results showed the effect of ionic radii and macrocycle size on ion selectivity as well as on the selectivity between non equivalent binding sites. The energy barriers of the preferential a, ±g,a conformational sequences present in the bound oxyethylene backbone were examined by molecular dynamics simulations using the MM+ force field in commercial software.

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Section: Resultssupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cation Complexation and Stereochemistry of Macrocycles Studied by 13C NMR Relaxation-Time Measurements

Erk

1999

NMR in Supramolecular Chemistry

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“…In order to understand the selectivity for the metals, it is of great significance to access the conformational properties as for the controlled molecular motions characteristic of 1,3-alternate-shaped calix [4]arene. Among NMR spectroscopic methods, it is known that NMR relaxation-time studies could provide further insights into the conformational properties and binding dynamics (11)(12)(13). Herein, we describe the 13 C NMR longitudinal relaxation times (T 1 ) studies on an ionophoric 1,3-alternate-shaped calix [4]arene ester 1, 1-Na ensemble and an acyclic analog 2 for the first time.…”

Section: Introductionmentioning

confidence: 99%

Carbon-13 NMR Longitudinal Relaxation Time Study of an Ionophoric 1,3-Alternate-Shaped Calix[4]arene Ester

et al. 2006

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Abstract:The carbon-13 NMR longitudinal relaxation times (T 1 ) studies on the 1,3-alternate-shaped calix[4]arene possessing two ester groups 1 in the absence and the presence of Na were carried out for the first time. The T 1 values were measured under proton-noisedecoupling conditions by the inversion-recovery technique. The T 1 -value of 1 is primarily governed by dipole-dipole relaxation. When calixarene 1 forms an ensemble with Na , the T 1 -values for all carbons are decreased. This suggests that the molecular motion of species 1 is efficiently frozen through complexation with Na . Eventually, Na ion plays an important role as a template ion specifically to freeze the fluctuational motion of two ethoxycarbonylmethoxybenzene units of 1.

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“…So, one of the central issues is how porphyrin-porphyrin interactions influence the electric properties of the dimer in calixarene. Among NMR spectroscopic methods, dynamic NMR studies (8) and NMR relaxation time studies (9)(10)(11) can provide useful information about the conformational properties. Herein, we describe the synthesis and 13 C NMR relaxation time (T 1 ) studies on the calixarene-substituted porphyrin derivatives 1, 2, and an acyclic analog 3 for the first time.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Carbon-13 NMR Longitudinal Relaxation Time Studies of Porphyrin Dimers Possessing Conformational Fluctuation

Arimura¹,

Nishioka²,

Kumamoto³

et al. 2004

J. Oleo Sci.

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Abstract:The synthesis and carbon-13 NMR longitudinal relaxation times (T 1 ) studies on the calixarene-substituted porphyrin dimers possessing conformational fluctuation were carried out for the first time. The T 1 values were measured under proton-noise-decoupling conditions by the inversion-recovery technique. The T 1 values for a calix[4]arene bridged porphyrin dimer 1 decrease with the increase in the solvent polarity. This implies that the T 1 values reflect the diffusion rate. As to a motion of the phenol unit, there are two different motions for phenol units in 1 and 2: a seesaw motion around a C-2 to C-2' axis (A) and a rotational motion around a C-1 to C-4 axis (B). The T 1 values indicate that in 1 motion (B) is predominant over motion (A). This shows that motion (A) is specifically suppressed because of the hydrogen-bonding interactions in 1.

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Self-complexation of macrocyclic polyethers studied by carbon-13 NMR longitudinal relaxation time measurements and molecular mechanics

Cited by 29 publications

References 0 publications

Cation Complexation and Stereochemistry of Macrocycles Studied by 13C NMR Relaxation-Time Measurements

Cation Complexation and Stereochemistry of Macrocycles Studied by 13C NMR Relaxation-Time Measurements

Carbon-13 NMR Longitudinal Relaxation Time Study of an Ionophoric 1,3-Alternate-Shaped Calix[4]arene Ester

Synthesis and Carbon-13 NMR Longitudinal Relaxation Time Studies of Porphyrin Dimers Possessing Conformational Fluctuation

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