To determine the structures of the ligand-exchanged materials, the lowest-angle peak, assigned to the (002) plane, was used to calculate the spacing between ZnSe layers (Table ). Computational models of each compound were constructed (see Experimental Section and Figure ), and experimental powder X-ray diffraction (PXRD) data were compared with these simulated models. Good agreement was found between the modelled (dmodel) and experimentally observed (dexp) distances between ZnSe layers (<5% deviation for all but one compound). For ZnSe(ea), ZnSe(ba), ZnSe(ha), and ZnSe(oa), excellent matches are found between dmodel and dexp (<2% deviation). When replacing ba with the longest alkylamines examined in this work, da and dda, dexp is 4% less than dmodel. We attribute this deviation to the simplicity of our model, which does not account for the possibility that the longer ligands may tilt to a greater extent than shorter ligands. Furthermore, gaps between longer ligands within the same ligand layer, left by residual unexchanged ba, would enable tilting of these longer ligands to a greater extent than evident in the idealized Direct analysis in real time mass spectrometry (DART-MS) was used to qualitatively examine the presence of the exchanged ligands (Figure ). All n-alkylamine substituted samples exhibit strong signals consistent with those expected for exchanged ligands (excepting ZnSe(ea), as the mass of ea is too low to observe in our instrument). Furthermore, only residual ba was observed for ZnSe(alkylamine) (<0.1% relative integrated intensity), indicating high ligand exchange yield (LEY) for those compounds. Thermogravimetric analysis (TGA) (Figures and) and elemental (CHN) microanalysis were used to independently quantify the achieved LEY. Equation S1 describes the method used to quantify LEY from TGA and CHN microanalysis. The results of both TGA measurements and CHN microanalysis are summarized in Table . Both methods show over 90% LEY in every n-alkylamine-exchanged compound. The high LEY in ZnSe(dda) suggests that we have not reached the limit of chain length that can be introduced into these materials via ligand exchange. Furthermore, these results show that the interlayer spacing can be adjusted at least over the range of 1.2 to 3.6 nm (ZnSe(ea) to (ZnSe(dda)).