2,6‐Dicarbonitrile Diphenyl‐1λ⁵‐Phosphinine (DCNP)—A Robust Conjugated Building Block for Multi‐Functional Dyes Exhibiting Tunable Amplified Spontaneous Emission

Abstract

Scheme 1. Details of synthetic route and chemical structures of investigated 2,6-dicarbonitrile-diphenyl-1λ 5 -phosphinine derivatives.

Amplified Spontaneous Emission from Zwitterionic Excited-State Intramolecular Proton Transfer

“…This can be attributed to relatively higher σ em and comparable k r of HBT-Fl2 , compared to HBT-Fl1 as can be seen in Figure S13 and Table . The obtained E th values for HBT-Fl2 blend films can be compared with previously reported high-performing laser dyes emitting in the wavelength range 580–740 nm (Figure S1 in the Supporting Information). ,− Clearly, the ASE E th of 5.3 μJ/cm 2 (λ ASE = 609 nm) for HBT-Fl2 is, to the best of our knowledge, one of the lowest thresholds reported for organic laser dye with emission wavelengths >600 nm, showing the promising potential of the zwitterionic ESIPT HBT-Fl2 for laser applications. Furthermore, it is worth noting that most reported materials show efficient performance only at very low doping concentrations (1–5 wt %) due to strong intermolecular interactions forming aggregates, while HBT-Fl2 demonstrates a low threshold at 10 wt % doping as well as in neat films.…”

Tuning the Charge Transfer in λ5-Phosphinines with Amino Substituents

“…( B , Figure ). , This outcome, rationalized by theory (see below), implies that the amino group is not involved in the transition responsible for the absorption, which is consistent with the neglectable solvatochromism in absorption (Figures S3–S6). This observation is also consistent with the X-ray structure of 3 showing a 90° angle between the DCNP fragment and the amino cycle.…”

“…All compounds display similar irreversible reduction waves characteristic of the DCNP ( E red = −2.17 V vs Fc + /Fc) (Table ). In agreement with Balijapalli et al ., all para-substituted DCNPs display two reversible oxidation waves (Figure S2), the first corresponding to the oxidation of the electron rich amino group and the second to the oxidation of the λ 5 -phosphinine ring. The trend in the first oxidation potential nicely follows the increasing donor strength in the 2 , 3 , 4 , 5 series (Table ).…”

Intrinsically switchable electroactive fluorophores based on lambda-5-phosphinine dimers

“…Such values fit with the oxidation reported for parasubstituted DCNP derivatives. 14 As observed in extended MV derivatives, the presence of aromatic π-linkers leads to a single redox process in DCNP dimers, indicating the absence of significant electronic communication between the two end-groups. 15 Note that the presence of the electro-withdrawing benzothiadiazole in 4 leads to the presence of a quasi-reversible reduction, making 4 an amphoteric redox system (Fig.…”