Study of weak interactions in two 1,2-diaryl-1,2,3,4-tetrahydroisoquinoline derivatives: influence of “organic fluorine” in crystal packing

The compounds 1-(2-fluorophenyl)-6,7-dimethoxy-2-phenyl-1,2,3,4-tetrahydroisoquinoline (1) and 5-(2-fluorophenyl)-6-phenyl-5,6,7,8-tetrahydro dioxolo[4,5-g]isoquinoline (2) have been studied via single crystal X-ray diffraction at 100.0(2) K. Compound 1 crystallizes in the space group $\text{P}\text{1}\text{̄}$ with two molecules in the asymmetric unit (Z=4), whereas compound 2 crystallizes in the space group P2₁/n. The two molecules of 1 in the asymmetric unit offer different modes of interactions via C–H…F and C–H…O resulting in altered molecular conformations. Compound 2 essentially packs via C–H…F interaction.