Abstract

Fatemeh Mosalanezhad¹*, Reza Mosalanezhad²

DOI : http://dx.doi.org/10.13005/ojc/300418

The kinetics and mechanism of the adduct formation of diorganotin(IV)dichlorides (R₂SnCl₂) where R=Ph, Me, Bu and triphenyltin(IV)chloride with Co(II) tetraaza Schiff base complexes such as: [Co(ampen)] {[N,N'-ethylenebis-(o-amino-α-phenylbenzylideneiminato)cobalt(ΙΙ)]}, [Co(campen)] {[N,N'-ethylenebis-(5-chloro-o-amino-α-phenylbenzylideneiminato)cobalt(II)]} and [Co(amaen)] {[N,N'-ethylenebis-(o-amino-α-methylbenzylideneiminato)cobalt(ΙΙ)]}, [Co(appn)]{[N,N'-1,2-propylenebis-(o-amino-α-phenylbenzylideneiminato)cobalt(ΙΙ)]}, [Co(cappn)]{[N,N'-1,2-proylenebis-(5-chloro-o-amino-α-phenylbenzylideneiminato-)cobalt(II)]} were studied spectrophotometrically. The kinetic parameters and the rate constant values show the acceptor tendency trend for the organotin(IV)chlorides as follow: Ph₂SnCl₂ > Me₂SnCl₂ > Bu₂SnCl₂> Ph₃SnCl Adducts have been separately synthesized and fully characterized by ¹¹⁹SnNMR, IR, Uv-Vis spectra and elemental microanalysis (C.H.N) methods. The trend of the rate constants for the adduct formation of the cobalt complexes with a given tin acceptor decreases as follow: [Co(amaen)] > [Co(appn)] > [Co(ampen)] > [Co(cappn)] > [Co(campen)]. The linear plots of k_obs vs. the molar concentration of the organotin(IV) chlorides, the high span of the second order rate costant k₂ values and the large negative values of ΔS^≠ and low ΔH^≠ suggest an associative (A) mechanism for the acceptor-donor adduct formation. Also [Co(aptn)]{[N,N'-1,3-propylenebis-(o-amino-α-phenylbenzylideneiminato)cobalt(ΙΙ)] and [Co(captn)]{[N,N'-1,3-proylenebis-(5-chloro-o-amino-αphenylbenzylideneiminato)cobalt (II)]} were synthesized and characterized but their kinetics with R₂SnCl₂ were very fast that we were unable to follow them using the conventional methods.

Diorganotin(IV)dichlorides; Kinetic; Mechanism; Tetraaza Schiff base; Cobalt(II) complex Triphenyltin(IV)chloride

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