Xu Wenjuan

A near-infrared phosphorescent probe for F− based on a cationic iridium(III) complex with triarylboron moieties

In this work, a near-infrared (NIR) phosphorescent probe for F− based on a cationic Ir(III) complex [Ir(Bpq)2(quqo)]PF6 (1) with dimesitylboryl (Mes2B) groups on the cyclometalated C∧N ligands (Bpq) and 2-(quinolin-2-yl)quinoxaline (quqo) as N∧N ligand was designed and synthesized. The excited state properties of 1 were investigated in detail using molecular orbital calculations and experimental methods. Upon excitation, complex 1 shows NIR phosphorescent emission around 680 nm. Interestingly, the complex can be excited with long wavelength around 610 nm. Such long-wavelength excitation can reduce the background emission interference and improve the signal-to-noise ratio. Furthermore, the selective binding between boron atom and F− can give rise to the quenching of emission and realize the near-infrared phosphorescent sensing for F−. We wish that the results reported herein will be helpful for the further design of excellent near-infrared phosphorescent probes based on heavy-metal complexes.

Optoelectronic Properties for Main Group Element-Bridged Ladder Compounds

Ladder-type π-conjugated molecules with fully ring-fused structures have fascinating optoelectronic properties because the flattened π-conjugated framework can eliminate conformational disorder and effectively enhance π-conjugation.Their optoelectronic properties can be modified by incorporating main group elements into the ladder skeleton.Heteroatom-bridges not only stiffen the skeleton but also contribute to the electronic structure through orbital interaction between the main group elements and the π-conjugated skeleton.Herein,the structural,electronic,and optical properties of bisand tetrakis-bridged(C,Si or P-bridged) stilbene derivatives were investigated by density functional theory(DFT) and time-dependent DFT(TDDFT) to provide theoretical understanding and predictions for these compounds.The electronic structures of these π-conjugated skeletons could be tuned by the incorporated elements.Compared with bis-bridged analogs,tetrakis-bridged derivatives exhibited substantial red shifts in the absorption and shorter radiative lifetimes because of extended π-conjugation.In addition,the energy barrier for the injection and transport rates of the holes and electrons was evaluated using ionization potentials,electronic affinities,and reorganization energies(λ).Compared to bis-bridged analogs,tetrakis-bridged derivatives exhibit higher accepting abilities for both holes and electrons.