Solid-state circularly polarised luminescence of atropisomeric fluorophores embedded in achiral myo-inositol-containing polyurethanes.

We investigated the ground- and photoexcited-state chiralities of two chiral fluorophores with a rigid framework embedded in two achiral polyurethanes as the solid matrices. As the fluorophores, we used two pairs of atropisomeric binaphthyl derivatives, (R)-(−)-1,1'-binaphthyl-2,2'-diyl hydrogen phosphate [(R)-1a] and (R)-(−)-(3,5-dioxa-4-phosphacyclohepta-[2,1-a:3,4-a']dinaphthalen-4-yl)-dimethylamine [(R)-1b], and for comparison, their optical antipodes (S)-1a and (S)-1b. As the solid matrices, we used two soluble achiral polyurethanes (2a and 2b) derived from the naturally occurring myo-inositol as the building block, because these polymers had a high glass transition temperature of ~150 °C. The chiral fluorophores in the polyurethanes emitted circularly polarised luminescence with a high circular anisotropy of ~0.6­1.5 × 10(-3). Regardless of the matrix, (R)- and (S)-1a had nearly mirror-image chiroptical properties in the ground and photoexcited states, as did (R)- and (S)-1b.

Enhancing circularly polarised luminescence by extending the π-conjugation of axially chiral compounds.

Circularly polarised luminescence (CPL) and photoluminescence (PL) properties of π-conjugated (R)- and (S)-2,2'-diphenyl-4-biphenanthrol (VAPOL) exhibited an efficient CPL (∼1.3 × 10(-3)) with a quantum yield (ΦF) of 0.20 at 376 nm. By comparison, (R)- and (S)-3,3-diphenyl-2,2-bi-1-naphthol (VANOL) exhibited no CPL or PL.

Pyrene magic: chiroptical enciphering and deciphering 1,3-dioxolane bearing two wirepullings to drive two remote pyrenes.

2,2-Dimethyl-1,3-dioxolane connected to two pyrene moieties through flexible wires in chloroform exhibited cryptochirality in the ground state, as proven by the lack of detectable circular dichroism signals. This cryptochirality was deciphered in the photoexcited state by circularly polarised luminescence signals.

Nonclassical dual control of circularly polarized luminescence modes of binaphthyl-pyrene organic fluorophores in fluidic and glassy media.

The fluorescent modes and signs of the circularly polarized luminescence of an axially chiral binaphthyl-pyrene organic fluorophore were successfully controlled by changing from a fluidic chloroform solution to a glassy poly(methyl methacrylate) solid film.

Sign inversion of circularly polarized luminescence by geometry manipulation of four naphthalene units introduced into a tartaric acid scaffold.

Tethering four 1- versus 2-naphthyls to the same chiral scaffold derived from tartaric acid led to oppositely signed circularly polarized luminescence (CPL) and circular dichroism (CD) in solution, which not only reveals the decisive role of the spatial arrangement of chromophores/fluorophores in determining the chiroptical behaviors but also provides us with a versatile tool for switching the signs of CPL and CD without using the antipodal scaffold.