Dipole moments and conformation of some aromatic benzamidoximes

1986 ◽  
Vol 51 (7) ◽  
pp. 1444-1449 ◽  
Author(s):  
Otto Exner ◽  
Nedelko Motekov
Keyword(s):  
Aromatic Ring ◽  
Benzene Solution ◽  
Dipole Moments ◽  
Mutual Position ◽  
Methoxy Groups

Dipole moments of aromatic benzamidoximes I - VI were measured in benzene solution. Assuming the Z configuration as established previously on another set of similar derivatives, some details of conformation could be determined, e.g. the position of an unsymmetrically substituted aromatic ring or mutual position of several methoxy groups.

Conformation around several equivalent bonds. Polymethoxy derivatives of benzene

1983 ◽  
Vol 48 (4) ◽  
pp. 1030-1041 ◽  
Author(s):  
Otto Exner ◽  
Václav Jehlička
Keyword(s):  
Dipole Moment ◽  
Crystalline Phase ◽  
Benzene Solution ◽  
Dipole Moments ◽  
Graphical Comparison ◽  
Methoxy Groups ◽  
Derivatives Of

Dipole moments of benzene methoxy derivatives I-IX were measured in benzene solution and discussed in terms of the conformation around the Car-O bonds, exploiting the method of graphical comparison and systematic introduction of substituents. In the case of 1,2-dimethoxybenzene several explanations are in accord with the dipole moment data. However, considering all available evidence, most probable seems to be the presence of two conformers, one of which is non-planar with two non-equivalent methoxy groups (IC). The conformation of 1,2,3-trimethoxybenzene is similar to that found for many derivatives in the crystalline phase (VC), only the outer methoxy groups are probably slightly deviating from the coplanar position.

Dipole moments induced in larger molecule. Long-chain aliphatic esters

1982 ◽  
Vol 47 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Otto Exner ◽  
Ayfer Bapçum
Keyword(s):  
Benzene Solution ◽  
Dipole Moments ◽  
Straight Chain ◽  
Basic Assumptions ◽  
Donor Acceptor ◽  
Eyring Theory ◽  
Aliphatic Esters ◽  
Long Chain

Dipole moments of straight-chain aliphatic esters Ia-Ic and IIa-IIf were measured in benzene solution. The observed trends are poorly reproduced by the classical Smith-Eyring theory; the reason may be partly the unknown conformation, partly even donor-acceptor complexes with the solvent. No deviations were observed with the highest members of the series, attributable to violation of some basic assumptions of the theory of dielectrics.

Dipole moments and conformation of α-disulphones. The gauche effect

1985 ◽  
Vol 50 (10) ◽  
pp. 2245-2251 ◽  
Author(s):  
Otto Exner ◽  
Václav Jehlička
Keyword(s):  
Dihedral Angle ◽  
Graphical Method ◽  
Benzene Solution ◽  
Dipole Moments ◽  
Statistical Treatment ◽  
X Ray ◽  
Gauche Effect

The dipole moments of substituted diphenyl disulphones I-III were measured in benzene solution and interpreted by the previously described graphical method. The results suggest an equilibrium of the ap and sc conformations in the ratio 3 : 1, at variance with various empirical rules and theories of the so-called gauche effect. A statistical treatment of X-ray data of various sulphonyl derivatives revealed essentially two preferred conformations: the more stable sc, with a broadened dihedral angle, and the less stable ap.

PHOSPHONITRILIC COMPOUNDS: PART I. THE MECHANISM OF PHOSPHONITRILIC CHLORIDE POLYMERIZATION CAPACITANCE, CONDUCTANCE, AND ELECTRON-SPIN RESONANCE STUDIES

1964 ◽  
Vol 42 (2) ◽  
pp. 447-455 ◽  
Author(s):  
H. R. Allcock ◽  
R. J. Best
Keyword(s):  
Free Radicals ◽  
Electron Spin Resonance ◽  
Electron Spin ◽  
Benzene Solution ◽  
Dipole Moments ◽  
Ring Cleavage ◽  
Preliminary Step ◽  
Polymerization Mechanism ◽  
Spin Resonance ◽  
Nitrogen Ring

Capacitance and conductance measurements were carried out with molten (NPCl2)3 and [NP(OC6H5)2]3 and dipole moments were determined in benzene solution. Attempts to detect free radicals in molten samples of the same compounds were unsuccessful. Evidence was obtained that homolytic or heterolytic phosphorus–nitrogen ring cleavage is not involved in the primary initiation process. The results favor, instead, a polymerization mechanism for (NPCl2)3 in which phosphorus–chlorine ionization is a preliminary step.

scholarly journals 2-Bromo-4,4-dimethyl-1-(2,4,5-trimethoxyphenyl)pentan-3-one

2009 ◽  
Vol 65 (6) ◽  
pp. o1359-o1359
Author(s):  
Lin-Lin Tang ◽  
Jiao Ye ◽  
Qi-Xing Liu ◽  
Ai-Xi Hu
Keyword(s):  
Crystal Structure ◽  
Aromatic Ring ◽  
Title Compound ◽  
Dihedral Angles ◽  
Compound C ◽  
Methoxy Groups

The three methoxy groups of the title compound, C16H23BrO4, are almost coplanar with the attached aromatic ring, forming dihedral angles of 7.19 (13), 2.48 (13) and 7.24 (12)°. The crystal structure shows an intramolecular and an intermolecular C—H...O interaction.

Hydrogen bonding, configuration and conformation of substituted α-oxo oximes and hydrazones

1979 ◽  
Vol 44 (8) ◽  
pp. 2494-2506 ◽  
Author(s):  
Otto Exner ◽  
Jorga Smolíková ◽  
Václav Jehlička ◽  
Ahmad S. Shawali
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Carbonyl Group ◽  
Intramolecular Hydrogen Bond ◽  
Benzene Solution ◽  
Dipole Moments ◽  
H Nmr ◽  
Intramolecular Hydrogen ◽  
Derivatives Of ◽  
Configuration And Conformation

Substituted 2-bromo-1-phenylglyoxal 2-phenylhydrazones IIIa-f exist in tetrachloromethane or benzene solutions prevailingly in E-configuration and in conformation A with an intramolecular hydrogen bond. The latter was evidenced by the N-H valence frequency at 3 290 cm-1 and by 1H NMR shifts with reference to derivatives without a carbonyl group - α-chlorobenzaldehyde phenylhydrazones V. From dipole moments of IIIa-d, measured in benzene solution, the contribution of the hydrogen bond (μH) was evaluated to 17 . 10-30 C m. This quantity is twice larger than in any other reported compound but the direction of the vector is as usual: approximately from H to N. In structurally similar derivatives of hydroxylamine, substituted 2-phenylglyoxylhydroximoyl chlorides IVa-d, no intramolecular hydrogen bond was detected; the dipole moments found were interpreted in terms of the Z-configuration and the prevailing conformation G.

A study of dipole moments of substituted isothiocyanates of 1,3-diphenyl-2-propen-1-one

1984 ◽  
Vol 49 (10) ◽  
pp. 2382-2386 ◽  
Author(s):  
Gejza Suchár ◽  
Milan Dzurilla ◽  
Pavol Kristian
Keyword(s):  
Electronic Structure ◽  
Benzene Solution ◽  
Dipole Moments ◽  
Vector Addition

The dipole moments have been measured of various substituted isothiocyanates of 1,3-diphenyl-2-propen-1-one in benzene solution. The measured values have been compared with the dipole moments obtained by the vector addition of the bond dipole moments, and the comparison has been used for a discussion of their electronic structure and interactions of the NCS group.

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