Crystal and molecular structure of trans-4-t-butylcyclohexanol parabromobenzoate

The crystal and molecular structure oftrans-4-t-butylcyclohexanol parabromobenzoate has been studied by X-ray crystallographic methods. Crystals of this compound are triclinic, space groupP¯1, with unit cell constantsa = 9·813(2),b = 13·451(3),c = 6·564(3) Å, α = 102·99(3), β = 98·88(3), γ = 89·99(3) ° andZ = 2. Using a GE XRD-6 diffractometer equipped with a scintillation detector, 3165 reflexions were measured to the limit 2θ = 140 ° for the Cu sphere. The structure was refined by least-squares methods toR (conventional) = 0·058. The main results of this study are:

1. no flattening is induced into the cyclohexane ring and there is no elongation of the C(t-bu)-C(cyclohexane) bond;
2. the steric strain introduced by thet-butyl group is minimized by a flattening of the C(4), C(3), C(7), C(5) pyramid;
3. the axial hydrogen atom on C(1) nearly eclipses the carbonyl oxygen, as found in the earlier studies of the acetates and esters of cyclohexanols.