A. Braibanti, F. Dallavalle, E. Leporati
Mar 1, 1971
Citations
0
Influential Citations
6
Citations
Journal
Inorganica Chimica Acta
Abstract
Abstract The equilibrium constants of DL-2-amino-4-hydroxybutyric acid (homoserine=hoser) have been determined potentiometrically; at 25°C±0.1 and μ=0.1 M KCl, they are log K 1 =9.257 (1), log K 12 =2.265 (1). The dependence upon ionic strength in the range 0.1–2 M KCl and upon temperature in the range 5–30°C have been also determined. The thermodynamic functions ΔH 1 =10.9 (4) kcal . mole −1 , ΔS 1 =5.9 (15) cal. mole −1 . degree −1 and ΔH 12 =0.3(4) kal . mole −1 , ΔS 12 =11.4 (13) cal . mole −1 . degree −1 are comparable with those of serine and threonine. The ligand forms with metals the complexes: Mn(hoser) + ; Co(hoser) + , Co(hoser) 2 ; Ni(hoser) + , Ni(hoser) 2 , Ni(hoser) − 3 ; Cu (hoser) + , Cu(hoser) 2 ; Zn(hoser) + , Zn(hoser) 2 , Cd(hoser) + . The equilibrium constants follow the Irving-Williams series. All the complexes contain very likely pentatomic chelate rings. By comparison with crystal structures of solid complexes and by considering the values of log K n /K n+1 some hypotheses are put forward on the structures of the complexes.