Conformational structure of poly[2-(dimethylamino)ethyl methacrylate], 2-(dimethylamino)ethyl pivalate and of their quaternary iodides. Vibrational and NMR spectra

1988 ◽  
Vol 53 (12) ◽  
pp. 3097-3107
Author(s):  
Bohdan Schneider ◽  
Jan Štokr ◽  
Jaroslav Straka ◽  
Martin Přádný ◽  
Stanislav Ševčík
Keyword(s):  
Spectral Analysis ◽  
Liquid State ◽  
Nmr Spectra ◽  
Quaternary Salt ◽  
Conformational State ◽  
Conformational Structure ◽  
Ethyl Group ◽  
Ethyl Methacrylate ◽  
C Nmr

Raman, infrared, and 1H and 13C NMR spectra of 2-(dimethylamino)ethyl pivalate, 2-(pivaloyloxy)ethyltrimethylammonium iodide, poly[2-(dimethylamino)ethyl methacrylate] and of its quaternary iodide were measured. Spectral analysis revealed that in crystalline 2-(dimethylamino)ethyl pivalate and in its quaternary salt, the 2-(dimethylamino)ethyl group exists in the g conformational state. In the liquid state, these compounds also contain a smaller amount of the t conformational structure of the 2-(dimethylamino)ethyl group. In poly[2-(dimethylamino)ethyl methacrylate] and in its quaternary iodide in solution, the population of the g and t conformational structures are similar to those found in 2-(dimethylamino)ethyl pivalate and in its quaternary iodide.

Conformational structure of ethylene glycol dibenzoate. Vibrational and NMR spectra

1981 ◽  
Vol 46 (8) ◽  
pp. 1913-1929 ◽  
Author(s):  
Bohdan Schneider ◽  
Pavel Sedláček ◽  
Jan Štokr ◽  
Danica Doskočilová ◽  
Jan Lövy
Keyword(s):  
Ethylene Glycol ◽  
Vibrational Spectra ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
H Nmr ◽  
Liquid States ◽  
Crystalline Forms ◽  
C Nmr

It was found that three crystalline forms of ethylene glycol dibenzoate can be prepared. Infrared and Raman spectra of these three forms, as well as of the glassy and liquid states, were measured. From 3JHH coupling constants obtained by analysis of the 13C satellite band of the -CH2- group in 1H NMR spectra, and from the 3JCH coupling constants of the -CO.O.CH2- fragment obtained by analysis of the carbonyl band in 13C NMR spectra it was found that in the liquid state the -CH2-CH2- group exists predominantly in the gauche conformational structure, and the bonds C-O-C-C assume predominantly a trans orientation. The results of the analysis of NMR and vibrational spectra were used for the structural interpretation of conformationally sensitive bands in vibrational spectra of ethylene glycol dibenzoate.

Conformational Structure of N-Methyl-8-octanelactam and Poly(N-methyl-8-octanelactam) as Studied by NMR, Infrared and Raman Spectroscopy and by Theoretical Calculations

1995 ◽  
Vol 60 (11) ◽  
pp. 1798-1808
Author(s):  
Jiří Dybal ◽  
Danica Doskočilová ◽  
Bohdan Schneider ◽  
Rudolf Puffr
Keyword(s):  
Nmr Spectra ◽  
Theoretical Calculations ◽  
Amide Bond ◽  
Conformational Structure ◽  
H Nmr ◽  
Infrared And Raman Spectroscopy ◽  
Stable Forms ◽  
Cis And Trans ◽  
Structure In Solution ◽  
C Nmr

It was proved by 1H and 13C NMR spectra that in N-methyl-8-octanelactam in CDCl3 solution, the amide bond assumes only the cis form. Mirror inversion about the plane of the amide bond occurs with an activation enthalpy ∆H# = 44.7 kJ/mol. Molecular mechanics and quantum mechanical calculations yielded four favoured conformational structures for the isolated molecule. By vibrational spectra, one of two distinguishable structures strongly predominates. From 1H NMR spectra, this predominant conformation was identified with one of the calculated stable forms. By 13C NMR evidence, poly(N-methyl-8-octanelactam) in tetrachloroethane solution contains equal populations of the cis and trans amide forms; the structure of this polymer in the rubbery solid state seems to be similar to its structure in solution.

Model compounds of poly(methyl methacrylate). Conformational structure of methyl 3-methoxy-2-methylpropionate

1984 ◽  
Vol 49 (10) ◽  
pp. 2275-2284 ◽  
Author(s):  
Danica Doskočilová ◽  
Jan Štokr ◽  
Bohdan Schneider ◽  
Martin Přádný ◽  
Stanislav Ševčík
Keyword(s):  
Methyl Methacrylate ◽  
Raman Spectra ◽  
Nmr Spectra ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
Model Compounds ◽  
Poly Methyl Methacrylate ◽  
C Nmr

By analysis of 1H and 13C NMR spectra, and of infrared and Raman spectra of methyl 3-methoxy-2-methylpropionate, the formation of conformers generated by rotation about the bonds CH3O-CH2, CH2-CH and C-C=O was studied. The structure of the most highly populated conformer is proposed.

Model compounds of poly(methyl methacrylate). Conformational structure of 2,2-dimethyl-1-methoxypropane and of the methyl ester of 3-methoxy-2,2-dimethylpropanoic acid

1983 ◽  
Vol 48 (11) ◽  
pp. 3050-3064 ◽  
Author(s):  
Bohdan Schneider ◽  
Danica Doskočilová ◽  
Jan Štokr ◽  
Jan Lövy ◽  
Martin Přádný ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Methyl Methacrylate ◽  
Nmr Spectra ◽  
Conformational Structure ◽  
Model Compounds ◽  
Poly Methyl Methacrylate ◽  
Major Form ◽  
C Nmr

By analysis of infrared, Raman and 13C NMR spectra of 2,2-dimethyl-1-methoxypropane and of the methyl ester of 3-methoxy-2,2-dimethylpropanoic acid, the formation of conformers generated by rotation about the CH2-OCH3 and C-CH2 bonds was studied. It was found that in both molecules, only the form with trans orientation of the C-CH2-O-CH3 bonds is present. The conformational structure of the major form of the methyl ester of 3-methoxy-2,2-dimethylpropanoic acid was proposed.

13C NMR spectra of 1-aryl-ferrocenylethylenes

1986 ◽  
Vol 51 (3) ◽  
pp. 670-676 ◽  
Author(s):  
Eva Solčániová ◽  
Štefan Toma ◽  
Tibor Liptaj
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Substituent Effects ◽  
13C Nmr Spectra ◽  
Bridge Group ◽  
C Nmr ◽  
Electron Effects

13C NMR spectra of 18 ferrocene analogues of trans stilbenes (1-aryl-2-ferrocenylethylenes) were measured. It was found that bridge group weakens the transfer of the substituent electron effects into ferrocene nucleus, especially distinctly into 3',4'positions of cyclopentadienyl ring. The transfer of substituent effects into β-position of the bridge -CH=CH- is greater in derivatives studied by us than in stilbenes. Synthesis of 1-(4-dimethylaminophenyl)-2-ferrocenylethylene is described.

The synthesis and stereochemistry of the ternary cobalt(III) complex with a stereospecific ligand derived from (S)-leucine

1986 ◽  
Vol 51 (2) ◽  
pp. 318-326 ◽  
Author(s):  
Milan Strašák ◽  
Pavol Novomeský
Keyword(s):  
Ir Spectroscopy ◽  
Aqueous Medium ◽  
Absorption Spectroscopy ◽  
Absolute Configuration ◽  
Nmr Spectra ◽  
Methyl Groups ◽  
Electron Absorption Spectroscopy ◽  
Electron Absorption ◽  
C Nmr

A new stereospecific ligand, ethylenediamine-N,N'-di(S)-α-isocapronic acid, was synthesized by condensation of (S)-leucine with 1,2-dibromoethane in alkaline aqueous medium. It follows from the 1H and 13C NMR spectra that the terminal methyl groups are chemically and magnetically nonequivalent. Of the four theoretically possible isomers of the ternary cobalt (III) complex with ethylenediamine, separation on catex yielded only one, whose absolute configuration was determined by a combination of 1H and 13C NMR, electron absorption spectroscopy and CD and IR spectroscopy.

17O and 13C NMR spectra of some geminal diacetates

1988 ◽  
Vol 53 (3) ◽  
pp. 588-592 ◽  
Author(s):  
Antonín Lyčka ◽  
Josef Jirman ◽  
Jaroslav Holeček
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
The Other ◽  
13C Nmr Spectra ◽  
Other Hand ◽  
Carboxylic Esters ◽  
C Nmr ◽  
Oxygen Atoms

The 17O and 13C NMR spectra of eight geminal diacetates RCH(O(CO)CH3)2 derived from simple aldehydes have been measured. In contrast to the dicarboxylates R1R2E(O(CO)R3)2, where E = Si, Ge, or Sn, whose 17O NMR spectra only contain a single signal, and, on the other hand, in accordance with organic carboxylic esters, the 17O NMR spectra of the compound group studied always exhibit two well-resolved signals with the chemical shifts δ(17O) in the regions of 183-219 ppm and 369-381 ppm for the oxygen atoms in the groups C-O and C=O, respectively.

Carbon-13 and nitrogen-14 NMR spectra of 1-(substituted phenyl)pyridinium salts

1980 ◽  
Vol 45 (10) ◽  
pp. 2766-2771 ◽  
Author(s):  
Antonín Lyčka
Keyword(s):  
Heavy Water ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Pyridinium Salts ◽  
Nmr Signals ◽  
C Nmr

The 13C and 14N NMR spectra of 1M solutions of 1-(substituted phenyl)pyridinium salts (4-CH3, 4-OCH3, H, 4-Cl, 4-Br, 4-I, 3-NO2, 4-NO2, 2,4-(NO2)2 (the 13C NMR only)) have been measured in heavy water at 30 °C. The 13C and 14N chemical shifts, the 1J(CH) coupling constants, some 3J(CH) coupling constants, and values of half-widths Δ 1/2 of the 14N NMR signals are given. The 13C chemical shifts of C(4) correlate with the σ0 constants (δC(4) = (1.79 ± 0.097) σ0 + (147.67 ± 0.041)), whereas no correlation of the nitrogen chemical shifts with the σ constants has been found. The half-widths Δ 1/2 correlate with the σ0 constants (Δ 1/2 = (76.2 ± 4.9) σ0 + (106.4 ± 2.2)) except for 1-phenylpyridinium chloride.

Synthesis of the six isomeric thieno[c]-fused 1,5- and 1,6-naphthyridines

1991 ◽  
Vol 56 (11) ◽  
pp. 2340-2351 ◽  
Author(s):  
Salo Gronowitz ◽  
Johan Malm ◽  
Anna-Britta Hörnfeldt
Keyword(s):  
Nmr Spectra ◽  
Coupling Reaction ◽  
One Pot ◽  
C Nmr

trough the use of Pd(0)-catalyzed coupling between 2- and 4-formyl-3-thiopheneboronic acids and 3-amino-2-bromopyridine and 4-acetamido-3-bromopyridine, convenient one-pot procedures for the preparation of thieno[2,3-c]-1,5-naphthyridine, thieno[3,4-c]-1,5-naphthyridine, thieno-[2,3-c]-1,6-naphthyridine, and thieno[3,4-c]-1,6-naphthyridine have been developed. In order to obtain thieno[3,2-c]-1,6-naphthyridine 2-(tributylstannyl)-3-thiophene aldehyde had to be used, since the organometallic partner in the coupling reaction, 3-formyl-2-thipheneboronic acid, is too easily deboronated. The effect of silver(I) oxide and thallium(I) carbonate on the coupling was studied. 1H and 13C NMR spectra of the six isomeric thieno{c]-fused 1,5- and 1,6-naphthyridines are discussed.

1H and 13C NMR spectra of 2,2’-disubstitutedtrans-azobenzenes suitable for preparation of metallized azo dyes

1991 ◽  
Vol 56 (10) ◽  
pp. 2160-2168 ◽  
Author(s):  
Josef Jirman
Keyword(s):  
Nmr Spectra ◽  
Electron Pair ◽  
Phenyl Group ◽  
Aprotic Solvents ◽  
1H And 13C Nmr ◽  
Predominant Form ◽  
Rapid Equilibrium ◽  
Dipolar Aprotic Solvents ◽  
Free Electron Pair ◽  
C Nmr

The 1H and 13C NMR spectra have been measured of six trans-azobenzenes substituted at 2 and 2’ positions with substituents favourable for complex formation with a metal (OH, NH2, NHCOCH3, COOH). From the standpoint of NMR such substituted trans-azobenzenes are present in solution in a rapid equilibrium following from rotation around the bond between C-1 of phenyl group and N atom of azo linkage. The predominant form has the substituent in the syn-position with respect to the free electron pair of the nearer azo nitrogen atom. The equilibrium is affected by dipolar aprotic solvents (such as hexadeuteriodimethyl sulfoxide) by decreasing the presence of the predominant form by 1 to 11%.

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