  Flux-grown single crystals of PuPt$_2$In$_7$ are characterized and found to
be both non-superconducting and non-magnetic down to 2 K. The Sommerfeld
specific heat coefficient of $\sim 250$ mJ/mol K$^2$ indicates heavy fermion
behavior. We report the results of generalized gradient approximation (GGA)+$U$
calculations of PuPt$_2$In$_7$ and as yet unsynthesized isovalent
PuPt$_2$Ga$_7$. The strength of the $c$-$f$ hybridization of PuPt$_2$In$_7$ is
similar to the PuCoIn$_5$ superconductor. The bare and $f$-weighted
susceptibility within the constant-matrix-element approximation is calculated,
showing a maximum along the $q_z$ direction at $q_x = q_y = 0.5$. A similar and
slightly stronger maximum is also found in the structurally related
heavy-fermion materials PuCoGa$_5$ and PuCoIn$_5$. The absence of
superconductivity in PuPt$_2$In$_7$ is examined based on the results of our
calculations.
