Synthesis and Solvatochromic Behavior of Pyrene Derivatives with 4-Hydroxyphenyl and 4-Hydroxyphenylethynyl Groups

Abstract 1-(4-Methoxyphenyl)pyrene (PyrPhOMe(1)), 1,3,6,8-tetrakis(4-methoxyphenyl)pyrene (PyrPhOMe(4)), 1-(4-methoxyphenylethynyl)pyrene (PyrC≡CPhOMe(1)), 1,3,6,8-tetrakis(4-methoxyphenylethynyl)pyrene (PyrC≡CPhOMe(4)), 1-(4-hydroxyphenylethynyl)pyrene (PyrC≡CPhOH(1)), and 1,3,6,8-tetrakis(4-hydroxyphenylethynyl)pyrene (PyrC≡CPhOH(4)) were synthesized via organometallic complex catalysis. Deprotection of the methoxy groups of PyrPhOMe(1) and PyrPhOMe(4) was conducted by treatment with BBr3. Deprotonation of the OH groups of PyrPhOH(1), PyrPhOH(4), PyrC≡CPhOH(1), and PyrC≡CPhOH(4) through treatment with NaH caused a bathochromic shift in the absorption and photoluminescence (PL) peaks. The bathochromic shift of the deprotonated species increased with the donor number (DN) of the solvents. These observations can be explained as the consequence of intramolecular charge transfer (ICT) from the ONa groups to the pyrene core.