Binaphthyl luminophores with triphenylsilyl groups: sign inversion of circularly polarized luminescence and circular dichroism

Abstract

C2-symmetric binaphthol derivatives bearing two bulky C3-symmetric triphenylsilyl side groups, open-style 3,3′-bis(triphenylsilyl)-1,1′-bi-2-naphthol and closed-style 3,3′-bis(triphenylsilyl)-1,1′-binaphthyl-2,2′-diyl hydrogenphosphate, emit circularly polarized luminescence (CPL) in the near-UV region when dissolved in chloroform and embedded into a poly(methyl methacrylate) film and KBr crystal. Despite the same axial chirality (S or R) of the binaphthol frameworks, the C3-symmetric triphenylsilyl side groups induced a sign inversion in the CPL and circular dichroism (CD) signals. The possibility of rotation of the C2-axis by the bulky groups determines the sign inversion of CPL and CD signals.