peri-Interactions in naphthalenes, 13 [1] 8-Dimethylamino-naphth-1-yl carbinols as model systems for potential N→Si/P interactions

In (8-dimethylamino-naphth-1-yl) ('DAN') carbinols DAN-C(OH)R1R2, the N atom can approach the HO group unto N⋯H-O hydrogen bond distance only when the steric conditions are favourable. The energy gain of such N⋯H-O interactions is insufficient to force R1 and R2 into otherwise unfavourable conformations. The geometry of the naphthalene may cause N, O and C atoms to reside in positions similar to those typical for hydrogen bonds though no N⋯H-O and N⋯H-C hydrogen bonds may actually be involved. By analogy, it seems unlikely that in peri-donor/acceptor substituted naphthalenes D-C10H6-A dative interactions (D→A) of similar or less energy as such N⋯H-O interactions can interfere with the geometry conserving forces of naphthalene and the steric effects of the peri substituents.