Calculated deformation energies of the isocyanurate rings in the isocyanurate molecules^a.

R	Symmetry
Primary alkyl-substituted isocyanurates
C 3 conformer
Me	C 3h	0.0
Et	C 3v	0.5
n-Pr	C 3	0.6
n-Bu	C 3	0.8
n-Hex	C 3	1.5
n-Oct	C 3	1.2
C s conformer
Me	C s	0.0
Et	C s	0.5
n-Pr	C s	0.4
n-Bu	C s	0.4
n-Hex	C s	0.4
n-Oct	C s	0.4
Secondary alkyl-substituted isocyanurates
i-Pr	C 3h	2.7
i-Pr	C s	2.7
Cy	C 3h	2.4
Tri-t-butyl isocyanurate
t-Bu	C s	23.4
t-Bu	C 3v	22.3
Triphenyl isocyanurate
Ph	D 3	−0.8

^aDeformation energies were calculated at the CCSD(T)/cc-pVTZ level (see the text), and the calculated values are provided in kcal mol⁻¹.