Warm molecular gas in the Galactic center region
  We present some recent studies on the physical conditions and the chemistry of the interstellar medium (ISM) in the Galactic center region (GCR). Large scale shocks in the context of a bar potential can play a role in explaining the observed properties, at least in some particular regions. Alternatively, we propose that the observed properties (inhomogeneity, high temperatures of the molecular gas, rich chemistry,...) of the GCR ISM can be the consequence of the recent past ($10^6-10^7$ years ago) of massive star formation in the GCR. 
N.J. Rodriguez-Fernandez, J. Martin-Pintado, P. de Vicente, A. Fuente