Structure of exo, endo, exo, exo-2,3,5,6-tetrabromonorbornane

Abstract

The compound, C7H8Br4, crystallizes in the triclinic space group P (1) over bar with a = 6.280(2) Angstrom, b = 6.646(3) Angstrom, c = 12.385(6) Angstrom, alpha = 96.58(4)degrees, beta = 90.50(3)degrees, gamma = 101.10(2)degrees, (V = 503.6(3) Angstrom(3), Z = 2, D-x = 2.715 Mgm(-3); Patterson method; 1542 hkl with I > 2 sigma(I); R = 0.048). The dihedral angles between the planar fragments C1-C2-C3(i)-C4(i) (A), C4(i)-C7-C1 (B) and C4(i)-C5-C6-C1(C) are 112.3(6)degrees, 124.5(8)degrees and 123.1(8)degrees for A-B, B-C and A-C, respectively. The deformations in the six-membered rings induced by the different substituents and by the methylene bridge show some difference with respect to the ideal values reported for a boat conformation. This difference reverberate on the internal torsion angles (C1 to C6: -0.7(9)degrees, -69.2(9)degrees, 65.8(9)degrees, 7.0(8)degrees, -76.6(8)degrees and 72.1(8)degrees).