How Realistic Are Interactions Involving Organic Fluorine in Crystal Engineering? Insights from Packing Features in Substituted Isoquinolines

Three new compounds have been synthesized based on the molecular motif, 6-methoxy-1,2-diphenyl-1,2,3,4-tetrahydroisoquinoline, with fluorine substitution at para, meta, and ortho positions on the 1-phenyl ring and a fluorine in the ortho position on the 2-phenyl ring. The crystal structures of all three compounds have been determined by single-crystal X-ray diffraction at 100.0(2) K. The three structures, as compared to the corresponding structures with no fluorine atom on the 2-phenyl ring, generate motifs via C−H···F and C−F···π interactions. None of these structures have any significant interactions other than those involving fluorine. The changes in both conformational features and in the intra- and intermolecular interactions involving fluorine provide significant inputs for understanding packing features associated with organic fluorine.