Stabilization of Excited State Using Through-Space Interaction between Independent π-Systems Mediated by a peri-Substituted Hydroxy Group in 1-Arylnaphthalenes: Unexpected Blue Emission of 1,3,5-Tris(peri-hydroxynaphthyl)benzene

Abstract

Abstract The control of photoluminescence wavelength is important for the design of emitting materials, and compounds bearing aryl–aryl bonds are considered to be useful candidates for the synthesis of these materials. However, the biaryl system lacks an efficient linkage of independent conjugated moieties because of a structure that, rather than planar, is made up of almost perpendicular dihedral angles due to steric effect. In this paper, we report a novel method to link independent π-systems in biaryl compounds. The oxy-substituents at the peri-position in 1-arylnaphthalene systems, which are biaryl compounds, showed interesting and unexpected photophysical properties of a bathochromic shift of emission. In particular, peri-OH-substituted arylnaphthalenes showed a large bathochromic shift that was induced by polarization based on intramolecular OH–aryl interaction. Quantum chemical (TDDFT) calculations accurately reproduced the large bathochromic shifts of peri-OH-substituted arylnaphthalenes. The through-space interaction between the peri-substituted OH and aryl groups generated an unexpected extended conjugation system. The substituting position of OH in 1-arylnaphthalenes is quite critical, because the hydroxy group mediates the independent π-systems to expand conjugation. Based on this concept, 1,3,5-tris(peri-hydroxynaphthyl)benzene had characteristic photophysical properties, giving an unexpected blue emission.