1-Iodoacétylènes. IV. Relations structure–réactivité pour la complexation des 1-iodoacétylènes substitués avec des bases de Lewis

1983 ◽  
Vol 61 (1) ◽  
pp. 135-138 ◽  
Author(s):  
Christian Laurence ◽  
Michèle Queignec-Cabanetos ◽  
Bruno Wojtkowiak
Keyword(s):  
Complex Formation ◽  
Triple Bond ◽  
Vibrational Frequency ◽  
Chemical Shifts ◽  
Structural Parameters ◽  
Equilibrium Constants ◽  
Lewis Acidity ◽  
Frequency Shifts ◽  
Substituent Constants ◽  
Substituted 1

The equilibrium constants for complex formation between the substituted 1-iodoacetylènes 1–8 and the vibrational frequency shifts induced by complex formation are related to the electronic substituent constants. The 13C chemical shifts of the triple bond are also useful structural parameters for predicting the Lewis acidity of iodoalkynes.

Chemical shifts for compounds of the group IV elements silicon and tin

1968 ◽  
Vol 46 (8) ◽  
pp. 1399-1414 ◽  
Author(s):  
B. K. Hunter ◽  
L. W. Reeves
Keyword(s):  
Chemical Shift ◽  
Complex Formation ◽  
Chemical Shifts ◽  
Equilibrium Constants ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Shielding Effect ◽  
Spin Lattice ◽  
Group Iv Elements

Chemical shifts for 29Si in seven series of molecules of the type XnSiY4−n have been measured where Y is an alkyl group and X varies widely in electronegativity. A considerable amount of proton and fluorine chemical shift data has been obtained for the same compounds and in one series (CH3)nSiCl4−n the 13C chemical shifts in the methyl groups have been measured.The gross features of the 29Si chemical shifts are understood by considering the series (Alkyl)3SiX with the electronegativity of X widely varied. The hybridization at silicon is approximately conserved in these series and the theoretically anticipated linear dependence on electronegativity of X is demonstrated. The ligands X = O, N, and F are exceptional and these 29Si chemical shifts have a high field shift. This additional shielding has been associated with (p → d)π bonding. The approximate nature of present chemical shift theories is not likely to provide a measure of the order of (p → d)π bonding.The 29Si chemical shifts in the series XnSiY4−n are discussed and also indicate a net shielding effect with (p → d)π bonding. A comparison is always made with corresponding 13C chemical shifts. A long range proton–proton coupling in molecules Me3SnX and Me2SnX2, H—C—Si—C—H, is observed when and only when X = O, (N?), F.119Sn chemical shifts in a series of alkyltin compounds have been measured. The same dependence on the electronegativity of X in the series (Alkyl)3SnX is noted, but the variation of X is much more limited. Some shielding due to (p → d)π bonding in the series (n-Butyl)nSnCl4−n is suggested. The tin chemical shift has been measured as a function of concentration and solvent for simple methyltin bromides and chlorides. In donor solvents, it has been possible to obtain equilibrium constants for complex formation from tin dilution chemical shifts. The nature of the bonding in complexes suggested previously is consistent with the variations in the coupling constant |JSn–C–H| with concentration. The distinction between ionization and complex formation with the solvent for (CH3)2SnCl2 can be made on the basis of the concentration dependence of |JSn–C–H|The spin–lattice relaxation time T1for 13C and 29Si in natural abundance in several pure degassed compounds has been measured. These are not in the case of 13C (as has been suggested) of the order several minutes, but are always less than 50 s and in one case as low as 3–4 s. Both 29Si and 13C T1 values follow what might be expected on the basis of a dipole–dipole mechanism from the closest protons. The short value of 35 s in CS2 is probably a result of spin–rotation interaction in the liquid state.

Vibrational frequency shifts of fluid nitrogen up to ultrahigh temperatures and pressures

1993 ◽  
Vol 97 (10) ◽  
pp. 2307-2313 ◽  
Author(s):  
George S. Devendorf ◽  
Dor Ben-Amotz
Keyword(s):  
Vibrational Frequency ◽  
Frequency Shifts ◽  
Vibrational Frequency Shifts

Ionic dissociation in complexes of iodine with triphenylarsine and triphenylstibine

1991 ◽  
Vol 69 (4) ◽  
pp. 606-610 ◽  
Author(s):  
Ying Ru Zhang ◽  
Ira Solomon ◽  
Seymour Aronson
Keyword(s):  
Complex Formation ◽  
Chemical Nature ◽  
Equilibrium Constants ◽  
Electrochemical Technique ◽  
High Iodine ◽  
Ionic Complex ◽  
Ionization Mechanisms ◽  
Iodine Complex ◽  
Ionic Dissociation ◽  
Iodine Complexes

An electrochemical technique has been employed to study the ionization of the iodine complexes of (C6H5)3As, (C6H5)3Sb, and pyridine. Several different ionization mechanisms are proposed depending on the chemical nature and concentration of the reactants. A new ionic complex, (C6H5)3MI22+ is postulated for the interaction of iodine with (C6H5)3As and (C6H5)3Sb at high iodine concentrations. Equilibrium constants have been calculated from the emf data for the various ionization steps. Key words: triphenylarsine, triphenylstibine, iodine, complex formation, ionization.

Correlations between 31P n.m.r. chemical shifts and structural parameters in crystalline inorganic phosphates

1986 ◽  
pp. 195 ◽  
Author(s):  
Anthony K. Cheetham ◽  
Nigel J. Clayden ◽  
Christopher M. Dobson ◽  
Roger J. B. Jakeman
Keyword(s):  
Chemical Shifts ◽  
Structural Parameters ◽  
Inorganic Phosphates

Vibrational frequency shifts and thermodynamic stabilities of (HF)n isomers (n=4–8)

1995 ◽  
Vol 245 (4-5) ◽  
pp. 319-325 ◽  
Author(s):  
Friedrich Huisken ◽  
Elena G. Tarakanova ◽  
Andrei A. Vigasin ◽  
Georgy V. Yukhnevich
Keyword(s):  
Vibrational Frequency ◽  
Frequency Shifts ◽  
Vibrational Frequency Shifts

scholarly journals DFT STUDIES OF STRUCTURAL PARAMETERS, VIBRATIONAL FREQUENCIES AND NMR SPECTRA OF 3-(1H-BENZO[D]IMIDAZOL-1-YL)-N'-(TOSYLOXY)PROPANIMIDAMIDE

2021 ◽  
pp. 15-25
Author(s):  
E.M. Yergaliyeva ◽  
◽  
L.A. Kayukova ◽  
A.V. Vologzhanina ◽  
G.P. Baitursynova ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Structural Parameters ◽  
Correlation Coefficients ◽  
Biological Properties ◽  
Vibrational Frequencies ◽  
Substitution Product ◽  
Bond Angles ◽  
Bond Lengths ◽  
B3lyp Level

Amidoxime derivatives have practically valuable biological properties. We have previously obtained new spiropyrazolinium compounds by arylsulfo-chlorination of β-aminopropioamidoximes, but in case of β-(benzimidazol-1-yl)pro-pioamidoxime we have obtained O-substitution product – 3-(1H-benzo[d]imidazol-1-yl)-N'-(tosyloxy)pro-panimidamide. The aim of the work is predicting of structural parameters (bond lengths, bond angles), vibrational frequencies and NMR spectra of 3-(1H-benzo-[d]imidazol-1-yl)-N'-(tosyloxy)propanimidamide. The calculations were performed using Gaussian 09 package. Structural parameters and vibrational frequencies was calculated using DFT (B3LYP/B3PW91/WB97XD)/6-31G(d,p). 1H and 13C NMR was predicted using DFT B3LYP/6-31G(d,p)-GIAO in DMSO. All calculated values are in good agreement with experimental data. The calculated bond lengths and bond angles were compared with results of X-ray structural analysis. The best correlation coefficient was 0.981 (calcu-lations with B3LYP level). For bond angles, the best result was obtained with B3LYP level (0.990). For vibrational frequencies correlation coefficients between the calculated and experimental values were 0.997 (B3LYP), 0.996 (B3PW91) and 0.995 (WB97XD). The most accurate method was used for predic-ting NMR spectrum. The correlation coefficients between the experimental and calculated 1H and 13C chemical shifts were 0.949 and 0.999 respectively.

Pressure effect on rate and equilibrium constants of reversible anionic .sigma.-complex formation between polynitroaromatics and lyate ions of water and methanol

1980 ◽  
Vol 102 (24) ◽  
pp. 7268-7272 ◽  
Author(s):  
Muneo Sasaki ◽  
Noboru Takisawa ◽  
Fujitsugu Amita ◽  
Jiro Osugi
Keyword(s):  
Complex Formation ◽  
Pressure Effect ◽  
Equilibrium Constants ◽  
Sigma Complex
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