The molecular distribution of the IRDC G351.77-0.51
  Infrared dark clouds are massive, dense clouds seen in extinction against the
IR Galactic background. Many of these objects appear to be on the verge of star
and star cluster formation. Our aim is to understand the physical properties of
IRDCs in very early evolutionary phases. We selected the filamentary IRDC
G351.77 - 0.51, which is remarkably IR quiet at 8{\mu}m. As a first step, we
observed mm dust continuum emission and rotational lines of moderate and dense
gas tracers to characterise different condensations along the IRDC and study
the velocity field of the filament. Our initial study confirms coherent
velocity distribution along the infrared dark cloud ruling out any coincidental
projection effects. Excellent correlation between MIR extinction, mm continuum
emission and gas distribution is found. Large-scale turbulence and line
profiles throughout the filament is indicative of a shock in this cloud.
Excellent correlation between line width, and MIR brightness indicates
turbulence driven by local star formation.
