ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 36, Number 2
JKCSEZ 36(2)
April 20, 1992 

The 2ν_C=O + amide III combination band spectrum of acetamide (AA) was obtained in very dilute solutions of AA+lanthanide shift reagents (LSR) in carbon tetrachloride over the range of 15。 to 45℃. It was found that only 1 : 1 AA-LSR complex is formed by the interaction between carbonyl oxygen of AA and central metal ion(Ln(Ⅲ)) in LSR. The thermodynamic parameters for Ln(Ⅲ)…O=C bond were determined by computer analysis of concentration and temperature dependent spectra. ΔH˚ for the coordination of AA to Eu(dpm)3, Yb(dpm)3, and Pr(dpm)3 have been found to be -39.1, -28.4, and -25.5 kJ/mol, respectively. It has shown that this type of ion-dipole interaction is more than twice stronger compared to the dipole-dipole interaction in the amide linkage, and largely depending on the steric hindrence effect by the bulky dpm groups around central metal ion (Ln(Ⅲ)) rather than the ionic potential effect of central metal ion itself.