Complex organic molecules in the Galactic Centre: the N-bearing family
  We present an unbiased spectral line survey toward the Galactic Centre (GC)
quiescent giant molecular cloud (QGMC), G+0.693 using the GBT and IRAM 30$\,$
telescopes. Our study highlights an extremely rich organic inventory of
abundant amounts of nitrogen (N)-bearing species in a source without signatures
of star formation. We report the detection of 17 N-bearing species in this
source, of which 8 are complex organic molecules (COMs). A comparison of the
derived abundances relative to H$_2$ is made across various galactic and
extragalactic environments. We conclude that the unique chemistry in this
source is likely to be dominated by low-velocity shocks with X-rays/cosmic rays
also playing an important role in the chemistry. Like previous findings
obtained for O-bearing molecules, our results for N-bearing species suggest a
more efficient hydrogenation of these species on dust grains in G+0.693 than in
hot cores in the Galactic disk, as a consequence of the low dust temperatures
coupled with energetic processing by X-ray/cosmic ray radiation in the GC.
