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The dimerization of some magnesacycloalkanes and benzomagnesacycloalkenes; the relation between ring size, ring strain and degree of association

1982; Elsevier BV; Volume: 240; Issue: 3 Linguagem: Inglês

10.1016/s0022-328x(00)86787-x

1872-8561

F.J.M. Freijee, G. Schat, Otto S. Akkerman, F. Matthias Bickelhaupt,

Thermal and Kinetic Analysis

Magnesacycloalkanes and benzomagnesacycloalkenes have a high tendency to dimerize. To relate this tendency to the ring size of the compounds, the degree of association i of magnesacyclohexane (I) (monomer/dimer equilibrium) [1], its 2,3-benzo-derivative II (monomer/dimer equilibrium), magnesacycloheptane (III) (i = 2), its 4,5-benzo-derivative IV (i = 1) and magnesacyclodecane (V) (i = 2) was determined. The reaction enthalpies for interaction of the compounds with proton donors were measured and the dimerization enthalpy, apparently equal to the ring strain in the monomers, was evaluated. The relationship between ring size, ring strain, and the degree of association is discussed.