BODIPYs (boron-dipyrromethenes) show an exceptional chemical stability and have been studied extensively. However, most BODIPYs have been limited to carbon-, heteroatom-, and halogen-modified systems.

Hua Lu, Hangzhou Normal University, China, and colleagues have synthesized and characterized a series of silyl- and disilanyl-BODIPYs through a transition-metal-catalyzed dehalosilylation of iodo-BODIPYs. Silyl and disilanyl substitutions significantly modify the spectroscopic properties of BODIPY.

Fluorescence quantum yields of silyl-BODIPYs were remarkably high, while the emission spectra of disilanyl-BODIPYs were red-shifted owing to an effective σ(SiSi)-π(BODIPY) conjugation. Emission of disilanyl-BODIPYs has an intramolecular charge-transfer (ICT) nature, involving electron transfer from the σ(SiSi) bond to the π-system, and is quenched in polar solvents. According to the researchers, these results could provide efficient access to many useful scaffolds in materials science.

• Silyl- and Disilanyl-BODIPYs: Synthesis via Catalytic Dehalosilylation and Spectroscopic Properties,
  Sisi Wang, Hua Lu, Yanping Wu, Xuqiong Xiao, Zhifang Li, Mitsuo Kira, Zhen Shen,
  Chem. Asian J. 2017.
  DOI: 10.1002/asia.201601637