Cooperative Adsorption of Carbon Disulfide in Diamine-Appended Metal– Organic Frameworks

Over one million tons of carbon disulfide are produced globally each year for an array of applications, and emissions of this highly volatile and toxic liquid, known to generate acid rain, remain poorly controlled. As such, materials capable of reversibly capturing this commodity chemical in an energy-efficient manner are of interest. Recently, we detailed a family of diamine-appended metal–organic frameworks capable of selectively capturing carbon dioxide through a cooperative insertion mechanism that promotes efficient adsorption–desorption cycling. We therefore sought to explore the fundamental ability of these materials to capture CS₂ through a similar mechanism. Employing crystallography, spectroscopy, and gas adsorption analysis, we demonstrate that CS₂ is indeed cooperatively adsorbed in N,N-dimethylethylenediamine-appended M₂(dobpdc) (M = Mg, Mn, Zn; dobpdc⁴⁻ = 4,4′-dioxidobiphenyl-3,3′-dicarboxylate), via the formation of electrostatically paired ammonium dithiocarbamate chains. Notably, in the weakly thiophilic Mg congener, chemisorption is cleanly reversible with mild thermal input. Importantly, this work demonstrates that the hitherto CO₂-specific cooperative insertion mechanism can be generalized to other high-impact target molecules.