Cyclopentannulated Dihydrotetraazapentacenes [Data]

The transition-metal catalyzed cyclization of bissilylethynylated N,N’-dihydro¬tetra¬aza¬pentacene (TIPS-TAP-H2) into bissilylated cyclo¬penta¬[fg,qr]¬pentacenes is reported. Depending on the catalyst either none, one or two silyl groups migrate and change their positions in the formed five-membered rings. The optoelectronic properties are quite similar, whereas the packing motifs differ dramatically. Control experiments and quantum chemical calculations were performed to investigate the mechanism of the reaction and the selectivity of the silyl shift.