Ion-Unquenchable and Thermally “On–Off” Reversible Room Temperature Phosphorescence of 3-Bromoquinoline Induced by Supramolecular Gels

Abstract

Ion-unquenchable and thermally on-off reversible room temperature phosphorescence (RTP) can be induced by entrapping 3-bromoquinoline (3-BrQ) into supramolecular gels formed by the self-assembly of a sorbitol derivative (DBS). In comparison with conventional substrates inducing RTP, the gel state 3-BrQ/DBS can produce strong RTP due to the efficient restriction of the vibration of 3-BrQ. Notably, the rather inconvenient deoxygenation is no longer necessary in the preparation of 3-BrQ/DBS gels. The produced RTP was found to be very fast to reach stable, not depending on the standing time. As a reference, in the liquid state of 3-BrQ/sodium deoxycholate (NaDC), stable RTP can be observed after standing for 5 h. The investigation of RTP quenching indicates that the mechanism of RTP induced by DBS gels mainly involves the microenvironment in which 3-BrQ is located. 3-BrQ was entrapped in the hydrophobic 3D network structure of DBS gels, thereby restricting the motion and collision of 3-BrQ and avoiding RTP quenching and additionally quenching by ions. Furthermore, the RTP of 3-BrQ/DBS gels show an excellent "on-off" effect at 10 or 80 °C. This indicates that the solid DBS gel is beneficial for the preparation of RTP sensor devices.

Phosphorescence Through Hindered Motion of Pure Organic Emitters

“…Another approach to induce room‐temperature phosphorescence by aggregation or hindered motion was described by Yang and co‐workers in 2015 (Figure ) . Their idea involved the trapping of 3‐bromoquinoline ( 20 ) inside supramolecular gels, which were formed by the spontaneous self‐assembly of sorbitol derivatives (DBS).…”

Organic Nanocrystals with Bright Red Persistent Room‐Temperature Phosphorescence for Biological Applications

“…As such, intensely phosphorescent materials are largely known to exist in inert gases and at very low temperatures,w hich in turn limits their practical applications. [20] So far,s everal strategies have been applied to minimize the intermolecular and intramolecular motions to activate the phosphorescence emission, which include hostguest doping systems with supramolecular gel entrapping, [21] metal-organic framework coordination [22] and rigid solid protection, [4] polymer assistance, [23,24] and crystal formation. [6][7][8][9][10][11][12][13] These discoveries sparked several attempts to find ag eneral strategy to design more of such materials for various applications.Itwas found that to yield efficient RTP, several key factors have to be considered.…”

“…[5] Recently,r esearchers discovered several examples of pure organic materials that exhibited persistent phosphorescence in air and at room temperature. [20] So far,s everal strategies have been applied to minimize the intermolecular and intramolecular motions to activate the phosphorescence emission, which include hostguest doping systems with supramolecular gel entrapping, [21] metal-organic framework coordination [22] and rigid solid protection, [4] polymer assistance, [23,24] and crystal formation. Thefirst is to promote intersystem crossing (ISC), and the second is to suppress the non-radiative relaxation pathways such as intermolecular motions.…”

Enhanced room temperature phosphorescence of palladium‐porphyrin by dual‐ordered structure of micelle‐hybridized supramolecular gels

“…Furthermore, the deoxygenation of the systems is usually required. Recently, we reported study on the RTP of 3‐bromoquinoline resided in supramolecular gels . The RTP of 3‐bromoquinolin was found to be ion‐unquenchable and thermally on–off reversible due to the unique ordered structure of supramolecular gels.…”