  In the recently synthesized Li$_x$(NH$_2$)$_y$(NH$_3$)$_z$Fe$_2$Se$_2$ family
of iron chalcogenides a molecular spacer consisting of lithium ions, lithium
amide and ammonia separates layers of FeSe. It has been shown that upon
variation of the chemical composition of the spacer layer, superconducting
transition temperatures can reach $T_c\sim 44 \mathrm{K}$, but the relative
importance of the layer separation and effective doping to the $T_c$
enhancement is currently unclear. Using state of the art band structure
unfolding techniques, we construct eight-orbital models from ab-initio density
functional theory calculations for these materials. Within an RPA
spin-fluctuation approach, we show that the electron doping enhances the
superconducting pairing, which is of $s_\pm$-symmetry and explain the
experimentally observed limit to $T_c$ in the molecular spacer intercalated
FeSe class of materials.
