Some Calculated Properties of Tetrahedrane

Other than its kinetic and thermodynamic stability (above), several properties of tetrahedrane are of interest, and can be readily calculated by current computational chemical techniques. Here we will look at four strain, ionization energy, acidity, and basicity. 

The use of isodesmic-type reactions (method (b)) to calculate the strain energy of tetrahedrane is shown (calculations by the author) it is instractive to examine 

So strain energy of bicyclobutane = -A/fi = 277.1 kJmol and strain energy of tetrahedrane = — (A/fi - - 

From the cation/neutral energy differerrce, IE = 0.31448 hartrees = 8.56 eV. From the HOMO of the neutral (Koopmans theorem), IE = 8.99eV. 

At the MP2/6-31G level, energy difference calctrlatiorts tend to imderestimate lEs by 0.1-0.7 eV [73] and Koopmans theorem to overestimate them by 1-1.5 eV, and to be fairly approximate [74]. Thus the IE of tetrahedrane is likely ea. 8.6 eV. Typical lEs of strained cycloalkanes ate ca. 8.6 eV (for cubane, cf 9.9 eV for cyclohexane) [75], so like another exotic cycloalkane, pyramidane (Chapter 2), tetrahedrane 

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