Correlation between the Nature of the Coordinated Organic Ligand and the Entropies and Volumes of Activation for Pyridine Additions to [Fe(CO)3 (1-5-ɳ-dienyl)] BF4 (dienyl = C6H7 or C7H9)

Detailed kinetic Studies of the reversible additions of 2 – benzylpyridine and 3 – iodopyridine to the [Fe(CO)3 (1-5- ɳ -dienyl) BF4 complexes (1; dienyl = C6 H7 or C7 H9) have been made as a function of temperature and pressure in acetonitrile using stopped flow techniques. The reported activation parameters (∆H≠, ∆S≠ and ∆V≠] for both the forward addition and reverse dissociation reactions are consistent with the operation of the previously suggested Odiaka’s ordered transition state” Mechanism. The results allow some quantitative information on the relationship between the nature of the coordinated Organic ligand in (1) and the degree of ordering in the transition state of the reactions between amines and organometallics of type (1).