醇和N,N-二甲基乙酰胺分子间相互作用的FTIR光谱研究

The association between alcohols and N,N-dimethylacetamide in carbon tetrachloride was investigated using FTIR spectroscopy at 298 K.The formation constants for 1∶1 and 1∶2 complexes were calculated using the method of Whetsel and Kagarise.The observed 1∶1 complex values were also verified using the method of Nash.The rate of change in C=O bond moment on complexing with alcohols increased with increasing acidity of alcohols.The formation constant and values of free energy change increased with the increase in carbon chain length of alcohols,which suggested that the degree of complex formation varied with the length of the carbon chain of alcohols.     

N-甲基甲酰胺与醇的氢键相互作用

The hydrogen bonding interactions between N-methylformamide and primary, secondary, and tertiary alcohols have been studied using the FT1R spectroscopic method. The most likely association complex between alcohol and N-methylformamide is the 1:1 stoichiometric complex formed between the hydroxyl group of alcohol and the carbonyl group of N-methylformamide. The formation constant of the 1:1 complexes has been calculated using the Nash method. It appears that the primary alcohols have larger formation constant compared with the secondary and tertiary alcohols. The results showed that the proton-donating ability of the alcohols decreased in the order: primary＞secondary＞tertiary, and that the association constant increased with the increase in carbon chain of the alkyl group of alcohols.     

EPR of an exchange-coupled,hydrogen-bridged one-dimensional Cu(II) complex containing both octahedral and square pyramidal geometries in the same unit cell

Single-crystal X and Q band EPR of a hydrogen-bridged l-dimensional Cu(II) complex, [Cu(stpy)₂(CH₃COO)₂(H₂O)₂] [CU(stpy)₂(CH₃COO) ₂(H₂O)], containing both octahedral and square pyramidal geometries in the same unit cell, has been studied at 300 K. EPR of powder samples at X band frequencies at 300 K and 77 K show exchange-narrowed resonance. The peak-to-peak linewidths of the signals are 80 G and 85 G, respectively. However, at Q band frequencies it exhibits an axially symmetric spectrum with spin Hamiltonian parameters g_|| = 2.303 and g_⊥ = 2.077, corresponding to an |x² ? y²〉 ground state. Single-crystal X band EPR spectra show a single resonance line for all the orientations, indicating the complex to be in the strong exchange regime. On the other hand, Q band spectra exhibit two lines corresponding to the weak exchange regime. An estimate of the interchain-site exchange coupling constant J′ = 0.0125(3) cm^?1 also reveals weak coupling between the magnetically distinct Cu(II) centres. The ratio of J′/J = 8.25 × 10^?2 is low enough to make the interactions almost l-dimensional, in agreement with X-ray data. EPR linewidth and lineshape analyses also support l-dimensional behaviour of the system.     

时域反射光谱法研究酰胺-醇混合物的介电驰豫

Using time domain reflectometry (TDR),dielectric relaxation studies were carried out on binary mixtures of amides (N-methylformamide (NMF) and N,N-dimethylformamide (DMF)) with alcohols (1-butanol,1-pentanol,1-hexanol,1-heptanol,1-octanol,and 1-decanol) for various concentrations over the frequency range from 10 MHz to 10 GHz at 303 K. The Kirkwood correlation factor and excess dielectric constant properties were determined and discussed to yield information on the molecular interactions of the systems. The relaxation time varied with the chain length of alcohols and substituted amides were noticed. The Bruggeman plot shows a deviation from linearity. This deviation was attributed to some sort of molecular interaction which may take place between the alcohols and substituted amides. The excess static permittivity and excess inverse relaxation time values varied from negative to positive for all the systems indicating that the solute-solvent interaction existed between alcohols and substituted amides for all the dynamics of the mixture.     

醇与丙烯酸酯的介电弛豫性质

Acrylic esters are industrially important chemicals, which are used as adhesives, paints, binders, and emulsifiers[1]. Alcohols play an important role in many chemical reactions because of their ability to undergo self-association with manifold internal s…     

N-甲基甲酰胺与醇的氢键相互作用

Amides are used as synthetic reagents and as starting mate- rials for the preparation of insecticides and pharmaceuticals products[1]. Alcohols are industrially and scientifically important organic compounds, and their physical and chemical properties are…     

时域反射光谱法研究酰胺-醇混合物的介电驰豫

Using time domain reflectometry （TDR）, dielectric relaxation studies were carded out on binary mixtures of amides （N-methylformamide （NMF） and N,N-dimethylformamide （DMF）） with alcohols （1-butanol, 1-pentanol, 1- hexanol, 1-heptanol, 1-octanol, and 1-decanol） for various concentrations over the frequency range from 10 MHz to 10 GHz at 303 K. The Kirkwood correlation factor and excess dielectric constant properties were determined and discussed to yield information on the molecular interactions of the systems. The relaxation time varied with the chain length of alcohols and substituted amides were noticed. The Bruggeman plot shows a deviation from linearity. This deviation was attributed to some sort of molecular interaction which may take place between the alcohols and substituted amides. The excess static permittivity and excess inverse relaxation time values varied from negative to positive for all the systems indicating that the solute-solvent interaction existed between alcohols and substituted amides for all the dynamics of the mixture.