The substituents which are deactivating but ortho para directing in aromatic substitutions is

 $\begin{array}{r}-{\mathrm{NO}}_2,-\mathrm{CHO},-\mathrm{F},-\mathrm{Cl},-\mathrm{Br},-\mathrm{OH},\\ -\mathrm{COCl},-{\mathrm{NH}}_2,-\mathrm{CN}\end{array}$

• When adding at the ortho- or para-position during electrophilic aromatic substitution, a carbocation intermediate with a resonance form that has a carbocation next to the directing group is produced. 
• The lone pair of halogens like fluorine, chlorine, and bromine can generate a pi-bond with the nearby carbocation. Halogens are generally deactivating, but this "pi donation" aids in stabilizing the transition state that results in ortho- or para-products, which is why they are ortho, para- directors. 

Therefore, the substituents which are deactivating are fluorine, chlorine, and bromine.