Kinetics and mechanism of adducts formation of tetraaza cobalt(II) complexes with some organic bases in DMF solvent |
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| Authors: | Mozaffar Asadi Zahra Asadi |
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| Institution: | 1. Chemistry Department, College of Sciences, Shiraz University, Shiraz, Islamic Republic of IranChemistry Department, College of Sciences, Shiraz University, Shiraz, Islamic Republic of Iran;2. Chemistry Department, College of Sciences, Shiraz University, Shiraz, Islamic Republic of Iran |
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| Abstract: | The kinetics and mechanism of the adduct formation of two Co(II) tetraaza complexes, Co(ampen)] {(N,N′‐ethylenebis‐(o‐amino‐α‐phenylbenzylideneiminato)cobalt(II)]} and Co(campen)] {(N,N′‐ethylenebis‐(5‐chloro‐o‐amino‐α‐phenylbenzylideneiminato)cobalt(II)]}, with four organic bases, 4‐nitro imidazole (4‐NO2Imid), 4‐methyl imidazole (4‐MeImid), imidazole (Imid), and 1‐methyl imidazole (1‐MeImid), in DMF were studied spectrophotometrically. The kinetic parameters and the second‐order k2 rate constants show the following nucleophilicity trend of the bases toward the given substrate: 4‐NO2Imid > 4‐MeImid > Imid > 1‐MeImid. The linear plots of kobs vs. the molar concentration of the base, the high span of k2 values, and the large negative values of ΔS≠ suggest an associative (A) mechanism. © 2007 Wiley Periodicals, Inc. 39: 137–144, 2007 |
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