Preparation and Optical and Electrochemical Properties of Boron (III) Subphthalocyanines with One to Three Trithiole Rings

The reaction of 5,6‐dicyano‐4,7‐diethylbenzo[1,2,3]trithiole ( 1 ) with trichloroborane in p ‐xylene and subsequent substitution of the chloro group with phenol produced boron (III) subphthalocyanine 2 with three trithiole rings. Upon treatment of 1 with trichloroborane in p ‐xylene in the presence of unsubstituted phthalonitrile or tetrafluorophthalonitrile, unsymmetrical subphthalocyanines 3 , 4 , 6 , and 7 with one or two trithiole rings were obtained after the reaction with phenol. The Q‐band absorption of 2 appeared at λ max =611 nm in the UV‐vis spectrum and the emission was observed at λ e =630 nm. Decreasing the number of fused trithiole rings and ethyl groups resulted in higher energy shifts of the Q‐band absorption in the UV‐vis spectra and downfield chemical shifts of the 11 B NMR signals. Compounds 2 , 3 , and 4 were treated by pentachloro antimonate in dichloromethane, the solution of which showed strong ESR signals. The structures of simplified model compounds were optimized using the DFT method with the Gaussian 09 program at the B3LYP/6‐31G (d, p) level.