Which ethanol derivatives display the gauche effect? How many of the following ethanol derivatives of the form $\ce{GCH2CH2OH}$ have a more stable gauche conformer compared to their anti conformer?
  
  $G =  \ce{F}, \ce{Cl}, \ce{OH}, \ce{NH2}, \ce{OMe}, \ce{NHMe}, \ce{NMe2}, \ce{NO2}$


I was sure that $\ce{F}$, $\ce{OH}$, $\ce{NH2}$ and $\ce{NO2}$ display the gauche effect. I'm not so sure regarding all the other groups: all of them seem bulky and won't form hydrogen bonds with the $\ce{OH}$ group on $\ce{C}_1$. How many of the other substituents are capable of displaying this effect? Also, is there a quantitative way to determine if the gauche conformer would be more stable than the anti conformer?
As per this source, there is evidence for the gauche effect for most of these groups on basis of intramolecular hydrogen bonding:


  


I tried looking for a similar evidence for 2-nitroethanol, and found this paper on the same:


  
  Figure 4. OCCN gauche structures with an intramolecular H-bond for 2-aminoethanol (7) and 2-nitroethanol (9); Conformations 8 and 10 indicate disrupted H-bonds after rotations by approximately 120º about the O-C axes


So it seems like all the groups shown here can show the gauche effect on the grounds of intramolecular hydrogen bonding,and so your answer should be 8