Structural complexity of a polar perhydrotriphenylene inclusion compound brought to light by synchrotron radiation

The complex diffraction pattern of the heavily disordered cocrystals of per hydrotriphenylene and 1-(4-nitrophenyl)piperazine (5C(18)H(30).C10H13N3O2) has been investigated with synchrotron radiation and an area detector. Five (almost) complete, three-dimensional data sets have been obtained from the tips and the centre of a needle-like crystal at room temperature and 120 K . They revealed a rich variety of features including one,- two- and three-d imensional diffuse scattering, as well as incommensurate satellites. At the centre and one tip of the crystal the symmetry appears to be orthorhombic. , whereas at the other tip the symmetry of the satellites and of some of th e diffuse scattering is clearly monoclinic, indicating that the crystal is not homogeneous. Most of the scattering could be assigned to RIS occupation al disorder of the chiral host molecules, to positional disorder of the gue st molecules or to local distortions of the average structure. Assignments are based on the disorder deduced from the average structure and the molecu lar form factors of host and guest molecules which show characteristic patt erns in reciprocal space. Two smaller, orthorhombic twin fragments and an a dditional phase with hexagonal symmetry have also been found.