Revealing Crystallization‐Induced Blue‐Shift Emission of a Di‐Boron Complex by Enhanced Photoluminescence and Electrochemiluminescence

Abstract

Elucidating the effects of crystallization‐induced blue‐shift emission of a newly synthesized di‐boron complex (DBC) by enhanced photoluminescence (PL) and electrochemiluminescence (ECL) in the annihilation pathway was realized for the first time. The 57 nm blue‐shift and great enhancement in the crystalline lattice relative to the DBC solution were attributed to the restriction of intramolecular rotation (RIR) and confirmed by PL imaging, X‐ray diffraction, as well as DFT calculations. It was discovered that ECL at crystalline film/solution interfaces can be further enhanced by means of both co‐reactant route and RIR. The RIR contributions with co‐reactant increased ECL up to 5 times more. Very interestingly, the co‐reactant system was found to give off a red‐shifted light emission. Mechanistic studies reveal that a difference between location of the ECL in the co‐reactant route and that in the annihilation pathway leads to an alternative emission wavelength.

Film Electrochemiluminescence Controlled by Interfacial Reactions Along with Aggregation‐, Matrix‐Coordination‐, and Crystallization‐Induced Emissions

“…Wong, Wang and Ding et al explored a newly designed diboron complex (DBC) seen in Figure 8 for its AIECL and CIECL properties hoping to uncover mechanisms by which solid luminescence could be enhanced. [51] First the ECL annihilation mechanism was investigated for both the crystalline and solution DBC states by loading 40 μg of DBC on a bare GCE in 2 : 1 ACN:water and with 0.25 mM DBC in ACN respectively. The 2 : 1 ACN:water mixture was chosen to prevent the film from dissolving off the surface of the bare GCE.…”

“…Wong, Wang and Ding et al. explored a newly designed di‐boron complex (DBC) seen in Figure 8 for its AIECL and CIECL properties hoping to uncover mechanisms by which solid luminescence could be enhanced [51] …”

“…Insets display the mechanisms of ECL emissions for both cases. Reprinted from ref [51]. with permission from Wiley-VCH.…”

“…(b) PL images of di-boron complex after recrystallization (left), gradual mechanical grinding (middle three images from left to right), and after exposure to acetone vapors for 24 hours (right). Reprinted from ref [51]. with permission from Wiley-VCH.…”

Optimizing the Electrochemiluminescence of Readily Accessible Pyrido[1,2‐α]pyrimidines through “Green” Substituent Regulation

“…Recently, by chemical linking electron‐rich triphenothiazines with electron‐deficient triazacoronenes, Zhang and co‐worker [24] prepared novel triphenothiazinyl triazacoronenes, and their fluorescence and ECL properties were verified relying on the donor or acceptor unit in the molecule. More recently, our groups [25] exploited a new avenue to modulate ECL emission of boron complexes by simple introduction of multiple boron centers within a single molecule, and the synthesized di‐boron complex shows strong crystallization induced emission via enhanced PL and ECL. Therefore, design, synthesis, and application of new, bright, and cost‐effective emitting organic molecules for ECL are a live research topic.…”