Variable-Temperature and -Pressure Kinetic Study of the Complexation of the Beryllium(II) Ion with 2-Amino-2,4,6-cycloheptatrien-l-one in N,N-Dimethylformamide

Article type: Research Article

Authors: Kato, Tadahiko | Aizawa, Sen-Ichi | Funahashi, Shigenobu

Affiliations: Laboratory of Analytical Chemistry, Faculty of Science, Nagoya University, Nagoya 464-01, Japan | Laboratory of Analytical Chemistry, Faculty of Engineering, Shizuoka University, Johoku, Hamamatsu 432, Japan

Note: [] Corresponding author.

Abstract: Kinetics of the formation and dissociation reactions of the 1:l complex of the beryllium(II) ion with 2-amino-2,4,6-cycloheptatrien-l-one in N,N-dimethylformamide (DMF) have been investigated spectrophotometrically at various temperatures and pressures. The rate constants at 298.2 K and the activation parameters are as follows: kf298 = 9.9 mol−1 dm3 s−1, ΔHf‡ = 50.4 ± 5.9 kJ mol−1, ΔSf‡ = -53 ± 20 J mol−1 K−1 and Vf‡ = −7.2 ± 3.9 cm3 mol−1 (298.2 K) for the formation and kd298 = 6.4 s−1, ΔHd‡ = 53.7 ± 0.9 kJ mol−1, ΔSd† = −49 ± 3 J mol−1 K−1, ΔVd‡ = −1.3 ± 1.3 cm3 mol−1 (298.2 K) for the dissociation. These results indicate that the reaction mechanism for the complexation of the beryllium(II) ion in DMF is associative in character. The volume profile for this reaction system is discussed in comparison with that for the related complexation.

DOI: 10.1080/10241229812331341389

Journal: Main Group Chemistry, vol. 2, no. 3, pp. 215-219, 1998