2,2′′,3,3′′,4,4′′,5, 5′′-Octa-phenyl-1,1′:4′,1′′-terphenyl and 2′,3′,5′,6′-tetra-fluoro-2,2′′,3, 3′′,4,4′′,5,5′′-octa-phenyl-1,1′: 4′,1′′-terphen-yl

The title compounds, C66H46, (I), and C66H42F4, (II), are polyphenyl-ated aryl-enes synthesized by one-step Diels-Alder cyclo-addition reactions. In both structures, all mol-ecules lie on crystallographic inversion centers. In the case of (I), there are two half-mol-ecules present in the asymmetric unit, (IA) and (IB); the geometry of each half-mol-ecule differs principally in the magnitudes of the dihedral angles between mean planes fitted through the central aryl ring and the pendant phenyl rings. The crystal used was a non-merohedral twin, with a refined twin scale factor of 0.460 (8). The dihedral angle between the plane of the central tetra-fluorinated ring and the adjacent tetra-phenyl-ated ring in (II) is 83.87 (4)°, significantly greater than the dihedral angles of 49.89 (12) and 54.38 (10)° found in the two half-mol-ecules in (IA) and (IB), respectively, and attributed to inter-molecular C - H⋯F hydrogen bonding in (II). Inter-molecular C - H⋯π bonding is found in (I). Two inter-actions have the C - H bond oriented towards the centroid (Cg) of a butadiene fragment of a phenyl ring; both H⋯Cg distances are approximately 2.68 Å and the inter-actions connect adjacent mol-ecules into stacks in the c-axis direction. The composition of the stacks alternates, i.e. (IA)-(IB)-(IA)-(IB) etc. A third, weaker, C - H⋯π inter-action and a phen-yl-phenyl close contact connect each end of the long mol-ecular axes of (IB) with an adjacent mol-ecule of (IA) into chains which run perpendicular to the (140) and ( 40) planes. C - H⋯F inter-actions in (II) have the most profound influence on the mol-ecular and crystal structure, the main effect of which is the above-mentioned increase in the dihedral angle between the plane of the central tetra-fluorinated ring and the adjacent tetra-phenyl-ated ring. C - H⋯F inter-actions have refined H⋯F distances of 2.572 (15) and 2.642 (16) Å, with approximate C - H⋯F angles of 123 and 157°, respectively. These form a hydrogen-bonded ribbon structure which propagates in the b-axis direction.