  We report on the on-surface synthesis of 7 armchair graphene nanoribbons
(7-AGNRs) substituted with nitrile (CN) functional groups. The CN groups are
attached to the GNR backbone by modifying the 7-AGNR precursor. While many of
these groups survive the on-surface synthesis, the reaction process causes the
cleavage of some CN from the ribbon backbone and the on-surface
cycloisomerization of few nitriles onto pyridine rings. Scanning Tunneling
Spectroscopy and Density Functional Theory reveal that CN groups behave as very
efficient n-dopants, significantly downshifting the bands of the ribbon, and
introducing deep impurity levels associated to the nitrogen electron lone
pairs.
