LOW-TEMPERATURE STRUCTURES OF CIS-4-TERT-BUTYLCYCLOHEXYL P-NITROBENZOATE (1) AND TRANS-4-TERT-BUTYLCYCLOHEXYL P-NITROBENZOATE (2)

cis- and trans-4-tert-Butylcyclohexyl p-nitrobenzoate, C17H23NO4, M(r) = 305.4. (1) cis isomer, triclinic, P1BAR, a = 6.3555 (7), b = 11.615 (4), c = 12.365 (4) angstrom, alpha = 111.44 (3), beta = 100.06 (2), gamma = 96.38 (2)degrees, V = 821.16 angstrom3, Z = 2, D(x) = 1.23 Mg m-3, lambda(Cu Kalpha) = 1.5418 angstrom, mu = 0.66 mm-1, F(000) = 328, T = 130 (2) K, R = 0.033 for 2237 unique observed reflections. (2) trans isomer, triclinic, P1BAR, a = 5.9963 (7), b = 15.511 (4), c = 17.244 (4) angstrom, alpha = 83.15 (2), beta = 89.73 (1), gamma = 87.94 (2)degrees, V = 1591.4 angstrom3, Z = 4, D(x) = 1.27 Mg m-3, lambda(Cu Kalpha) = 1.5418 angstrom, mu = 0.64 mm-1, F(000) = 656, T = 130 (2) K, R = 0.032 for 4504 unique observed reflections. Structure (2) consists of two independent molecules in the asymmetric unit, which have essentially identical conformations. In both structures the ester function adopts the preferred Z configuration. The axial C-OPNB (PNB = p-nitrobenzoate) bond length in (1) is 1.473 (2) angstrom, which is slightly longer than the two equatorial C-OPNB bond lengths observed in (2) [C(1)-O(1) and C(1')-O(1') for the two molecules are 1.463 (2) and 1.468 (2) angstrom, respectively].