Studies on the Base Strengths of N,N-Disubstituted Amides

Adelman, Robert L.

doi:10.1021/jo01030a041

Cited by 32 publications

(12 citation statements)

References 2 publications

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“…The C--O stretching frequency for the individual dialkyl amides was less when adsorbed on trimethylammoniummontmorillonite than on the tetramethylammonium system. However, the stretching frequencies for both systems were less than those reported for the amides dissolved in isooctane (Adelman, 1964) or those found for the liquid amides. A positive linear relationship was found between the C--O stretching frequency change (Auco) and the N--H stretching frequency change (AuNH) when dialkyl amides were adsorbed on trimethylammonium-montmorillonite (Fig.…”

Section: Resultscontrasting

confidence: 66%

“…A summation of the electron withdrawing constants or Taft polar factors (~*), provides a theoretical basis for estimating relative basicity of compounds independent of steric considerations. Adelman (1964) found a linear relationship between summation of Taft polar 265 factors (2o-*) and basicity when formamides and acetamides were the electron donors and HC104 was the electron acceptor.…”

Section: Introductionmentioning

confidence: 95%

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Intermolecular Interaction in Montmorillonites: NH-Co Systems

Doner

1969

Clays and clay miner.

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Abstract-The mechanism of interaction between cationic organic molecules satisfying exchange sites in montmorillonite and organic molecules with carbonyl groups was investigated. Dialkyl amides adsorbed on trimethyl-ammonium-and tetramethylammonium-montmorillonite were studied by i.r. spectroscopy. The electronegativity or basicity of the amides, expressed as a summation of the Taft polar factors (Ecr*), was found to be linearly related to the C-O stretching frequency after adsorption on trimethyl-ammonium-montmorillonite. Furthermore, the changes in the C--O and N--H stretching frequencies of the amides and trimethylammonium ion respectively, exhibited a direct linear relationship. Thus, the dialkyl amides were shown to be hydrogen bonded through the oxygen of the carbonyl group to the hydrogen of the trimethylammonium. The (001) spacing of trimethyl-ammonium-montmorillonite was 12-9 A. Only after the adsorption of amide molecules of the size of N,N-diethylacetamide or larger did this spacing change. Dialkyl amides were adsorbed on tetramethylammonium-montmorillonite, but less energetically than on trimethylammoniumclay. The (001) spacing of tetramethylammonium-montmorillonite was 13.8 A and remained the same after adsorption of the dialkyl amides. Evidence of hydrogen bonding between the hydrogen of trimethylammonium-ion and some other carbonyl compounds was also noted.

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Section: Resultscontrasting

confidence: 66%

Section: Introductionmentioning

confidence: 95%

Intermolecular Interaction in Montmorillonites: NH-Co Systems

Doner

1969

Clays and clay miner.

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“…(11), (12), (19), and (20) reflecting the law of mass action and Eqs. (21)3 (23) reflecting the conditions of material balance and electroneutrality, we calculated the apparent association constants b I at 278 K (0.01 < Q SO 2 < 0.05 M): (23) where Q Am is the total Am content in the system.…”

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confidence: 99%

Interaction of Sulfur Dioxide with Aqueous Solutions of Amides

2005

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The interactions in the systems H 2 O3Am3SO 2 (Am is formamide, dimethylformamide, acetamide, urea, tetramethylurea, tert-butylurea) at 278 and 293 K were studied pH-metrically. The results suggest formation of intermolecular and ion3molecule associates. The composition and stability of the compounds formed strongly depend on the structure and concentration of the solution components and on temperature.The possible reactions of SO 2 with compounds of various classes are very diverse, and studies of the behavior of SO 2 in aqueous solutions are of not only theoretical but also practical importance [1].

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“…This order is surprising, since D M F is a weaker electron donor than DNA-toward phenol (12,13). I t may be that the CH proton in D n I F functions as a weak hydrogen donor to the oxygen of water, the protons of which are bonded to other D n l F molecules.…”

Section: Resultsmentioning

confidence: 99%

Proton magnetic resonance study of water as hydrogen donor to N,N-dimethylformamide and dimethyl sulfoxide

Ting¹,

Wang²,

Li³

1967

Can. J. Chem.

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1. B. E. CONWAY, E. GILEADI, and H. G. OSWIK.Can. J. Chem. 41,2447Chem. 41, (1963 638 (1962).3. C. W. TOBIAS and R. WIJSMAN. J. Electrochem. Soc. 100,459 (1953). 4. J . S. NEWMAN and C. \V. TOBIAS. J. Electrochem. Soc. 109,1183 (1962 Proton magnetic resonance study of water as hydrogen donor to N,N-dimethylformamide and dimethyl sulfoxideSeveral papers (1-5) have appeared on the use of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) as soivents for the proton magnetic resonance (p.m.r.) study of hydrogen bonding involving nucleosides. The use of these nonaqueous solvents is necessary because in aqueous medium the hydrogen atoms directly involved in bonding exchange rapidly with water protons; moreover, the use of water as solvent produces complications with purines and pyrimidines. The choice of DAIS0 and DNIF has been made because these provide adequate solubility without proton transfer. I t becomes of interest therefore to obtain thermodynamic data of water acting as hydrogen donor to D k I F and DAISO, and the results are presented here. EXPERIMENTAL MaterialsDh'ISO was deuterated by the method of Buncel et al. ( 6 ) in order to decrease the intensity of the proton signal which would interfere with the measurement of the water proton signal. DMF was distilled from calcium carbide. Carbon tetrachloride and cyclohexane were distilled. All compounds were kept over a Linde molecular sieve. InstrumentalAll nuclear magnetic resonance (n.m.r.) spectra were obtained with a Varian Associates model A-60 n.m.r. spectrometer. During the taking of the spectra the temperature remained constant to within & l o , as indicated by the separation in c.p.s. between two peaks in ethylene glycol or methanol. Chemical shifts of the water proton signal were measured with respect to tetramethylsilane (TMS) as an internal standard and all lines are downfield from it. A side band of TMS was placed before and after the water resonance peak a t a separation of about 10 c.p.s. The side-band frequencies were measured with a audio oscillator and a frequency counter. The reported shifts are accurate to about 0.3 C.P.S.Samples for p.m.r. measurements were prepared as described in previous papers ( 7 , s ) . RESULTSThe chemical shifts of the water proton signal, v, in ternary system containing D M F or DPISO of mole fraction Xdl water (in the concentration range of Canadian Journal of Chemistry. Volume 45, 425 (1967) Can. J. Chem. Downloaded from www.nrcresearchpress.com by 54.245.13.81 on 05/12/18For personal use only.

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Studies on the Base Strengths of N,N-Disubstituted Amides

Cited by 32 publications

References 2 publications

Intermolecular Interaction in Montmorillonites: NH-Co Systems

Intermolecular Interaction in Montmorillonites: NH-Co Systems

Interaction of Sulfur Dioxide with Aqueous Solutions of Amides

Proton magnetic resonance study of water as hydrogen donor to N,N-dimethylformamide and dimethyl sulfoxide

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