Interlocking molecular grid lattices involving weak assembly forces

The X- ray structures of the two diquinoline derivatives 6,13- dihydro- 6,13- ethano- 5,12- diazapentacene ( 1) and 6alpha, 13alpha- dibromo- 2,9- dichloro- 5balpha, 6,12balpha, 13- tetrahydropentaleno[ 1,2- b: 4,5- b'] diquinoline ( 2) reveal that both crystallise by forming network lattices involving only weak intermolecular forces. These very similar lattices contain no aryl edge - edge C - H ... N R-2(2) ( 8) dimers or efficient aryl offset face - face interactions, commonly found in related diquinoline crystals. Both lattices arise from multiple interlocking, at an inclined angle, of two identical sets of parallel molecular grids. Each grid connector site comprises a centrosymmetric tetramer of molecules held together by weak intermolecular forces, unlike the metal co- ordination motifs normally used to generate grid structures. Edge - edge C - H ... N weak hydrogen bonds of various types help stabilise these structures by linking molecules of opposite handedness in neighbouring grids.