Dinaphthobenzo[1,2:4,5]dicyclobutadiene: Antiaromatic and Orthogonally Tunable Electronics and Packing.

Polycyclic conjugated hydrocarbons containing antiaromatic four-membered cyclobutadienoids (CDB) are of great fundamental and technical interest. However, their challenging synthesis has hampered the exploration and understanding of such systems. Reported herein is a modular and efficient synthesis of novel CBD-containing acene analogues, dinaphthobenzo[1,2:4,5]dicyclobutadiene (DNBDCs), with orthogonally tunable electronic properties and molecular packing. The design also features strong antiaromaticity of the CBD units, as revealed by nucleus-independent chemical shift and anisotropy of the induced current density calculations, as well as X-ray crystallography. Tuning the size of silyl substituents resulted in the most favorable "brick-layer" packing for triisobutylsilyl-DNBDC and a charge mobility of up to 0.52 cm2  V-1  s-1 in field-effect transistors.