Fig. 5
From: Cooperative adsorption of carbon disulfide in diamine-appended metal–organic frameworks
Spectroscopic characterization of CS2 Adsorption. a In situ diffuse reflectance FT–IR spectra collected upon exposure of activated mm-2–Mg2(dobpdc) and isopentylamine–Mg2(dobpdc) to the vapor pressure of CS2 at 25 °C. Effects from physisorbed CS2 on the framework have been subtracted as the baseline to generate difference plots. Two different sets of distinct bands corresponding to new C–S (left) and C–N (right) vibrations are observed for mm-2–Mg2(dobpdc) (red traces), but not isopentylamine–Mg2(dobpdc) (blue traces). This observation is in agreement with the presence of two distinct ammonium dithiocarbamate chain conformations. b In situ NEXAFS spectra collected at the N K-edge upon exposure of activated mm-2–Mg2(dobpdc) (left) and activated mm-2–Zn2(dobpdc) (right) to the vapor pressure of CS2 at 25 °C. After exposing the activated samples to CS2, the environmental cell was evacuated to remove physisorbed CS2 before the measurement was taken. Both congeners show a new pre-edge feature and a shift of the main edge upon CS2 exposure, indicative of ammonium dithiocarbamate formation. All major spectral changes have been computationally reproduced (Supplementary Figures 68–71)
