# Synthesis and characterizations of highly luminescent 5-isopropoxybenzo[rst]pentaphene

## TL;DR

Scientists made a new compound with a high light-emitting ability, which could be useful as a fluorescent material.

## Contribution

The synthesis and characterization of BPP-OiPr with a significantly enhanced photoluminescence quantum yield.

## Key findings

- BPP-OiPr has a PLQY of 73%, much higher than pristine BPP's 13%.
- BPP-dione shows improved optical properties with a PLQY of 62% and charge-transfer character.
- The BPP derivatives form rod-like nano- to microcrystals and longer wires.

## Abstract

A benzo[rst]pentaphene (BPP) substituted by an isopropoxy group (BPP-OiPr) was synthesized in a facile manner. Its photophysical properties were investigated by UV–vis absorption and fluorescence spectroscopy in compassion to pristine BPP and its oxidation product, benzo[rst]pentaphene-5,8-dione (BPP-dione). BPP-OiPr exhibited a significantly enhanced photoluminescence quantum yield (PLQY), reaching 73% in comparison to pristine BPP (13%). BPP-dione, when compared to the parent BPP, also displayed improved absorption and emission from the first excited singlet (S1) state with a PLQY of 62% and an intramolecular charge-transfer character. The rod-like nano- to microcrystals as well as longer wires of these BPPs were also revealed by scanning electron microscopy. The intriguing optical properties of BPP and its derivatives may lead to their application as fluorophores.