Distannabarrelenes with Three Coordinated SnII Atoms

Crystalline 1,4-distannabarrelene compounds (ADC^Ar)₃Sn₂]SnCl₃ ( 3 - Ar ) (ADC^Ar={ArC(NDipp)₂CC}; Dipp=2,6-iPr₂C₆H₃, Ar=Ph or DMP; DMP=4-Me₂NC₆H₄) derived from anionic dicarbenes Li(ADC^Ar) ( 2 - Ar ) (Ar=Ph or DMP) have been reported. The cationic moiety of 3 - Ar features a barrelene framework with three coordinated Sn^II atoms at the 1,4-positions, whereas the anionic unit SnCl₃ is formally derived from SnCl₂ and chloride ion. The all carbon substituted bis-stannylenes 3 - Ar have been characterized by NMR spectroscopy and X-ray diffraction. DFT calculations reveal that the HOMO of 3 - Ph (ϵ=−6.40 eV) is mainly the lone-pair orbital at the Sn^II atoms of the barrelene unit. 3 - Ar readily react with sulfur and selenium to afford the mixed-valence Sn^II/Sn^IV compounds (ADC^Ar)₃SnSn(E)](SnCl₆)_0.5 (E=S 4 - Ar , Ar=Ph or DMP; E=Se 5 - Ph ).