Structural insights into methyl- or methoxy-substituted 1-(α-aminobenzyl)-2-naphthol structures: The role of c—h⋅⋅⋅π interactions

Aminobenzylnaphthols are a class of compounds containing a large aromatic molecular surface which makes them suitable candidates to study the role of C—H⋅⋅⋅π interactions. We have investigated the effect of methyl or methoxy substituents on the assembling of aromatic units by preparing and determining the crystal structures of (S,S)-1-(4-methylphenyl)[(1-phenylethyl)amino]methylnaphthalen-2-ol, C 26 H 25 NO, and (S,S)-1-(4-methoxyphenyl)[(1-phenylethyl)amino]methylnaphthalen-2-ol, C 26 H 25 NO 2 . The methyl group influenced the overall crystal packing even if the H atoms of the methyl group did not participate directly either in hydrogen bonding or C—H π interactions. The introduction of the methoxy moiety caused the formation of new hydrogen bonds, in which the O atom of the methoxy group was directly involved. Moreover, the methoxy group promoted the formation of an interesting C—H⋅⋅⋅π interaction which altered the orientation of an aromatic unit.