in neat (no solvent, solid phase) byproducts: (CH3)3SiCN; under N2; the B complex was heated in a Pyrex tube at 250°C for 1.5 h under dynamic vac.; BC3N3 formed near the bottom of the tube, starting B(CN)3(NCSi(CH3)3) sublimed to the top of the tube; elem. anal.;