ISSN:
1572-901X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Summary The kinetics and mechanism of ligand substitution reactions of tetraethylenepentamine nickel(II), Ni (Teren), and triethylenetetraamine nickel(II), Ni(Trien), with 4-(2-pyridylazo)resorcinol (parH2) have been studied spectrophotometrically at I=0.1 M (NaClO4) at 25°C. In both systems two distinct reaction steps are observed. The rapid first step follows the rate law d[Ni(Polyamine)(ParH2)]/dt=k1 [Ni(Polyamine)] [ParH2]. The formation of ternary complexes of Ni (Polyamine) with ParH2 has been investigated under second order equal concentration conditions. The values of second order rate constants for the Trien and Teren reactions are (2.1±0.2)×104 M−1s−1 and (7.8±0.6)×103 M−1s−1 respectively at pH=9.0, I=0.1 M and 25°C. The rate law for the second step may be written as d[Ni(Par)2]/dt=k2[Ni(Polyamine)(ParH2)]. Values of k2 for the Trien and Teren systems are (2.5±0.1)×10−4 s−1 and (4.76±0.3)×10−5 s−1 respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01024320
