Chemically Resistant, Shapeable, and Conducting Metal-Organic Gels and Aerogels Built from Dithiooxamidato Ligand

Metal-organic gels (MOGs) appear as a blooming alternative to well-known metal-organic frameworks (MOFs). Porosity of MOGs has a microstructural origin and not strictly crystalline like in MOFs; therefore, gelation may provide porosity to any metal-organic system, including those with interesting properties but without a porous crystalline structure. The easy and straightforward shaping of MOGs contrasts with the need of binders for MOFs. In this contribution, a series of MOGs based on the assembly of 1D-coordination polymer nanofibers of formula [M(DTA)] n (M-II: Ni, Cu, Pd; DTA: dithiooxamidato) are reported, in which properties such as porosity, chemical inertness, mechanical robustness, and stimuli-responsive electrical conductivity are brought together. The strength of the M. S bond confers an unusual chemical resistance, withstanding exposure to acids, alkalis, and mild oxidizing/reducing chemicals. Supercritical drying of MOGs provides ultralight metal-organic aerogels (MOAs) with densities as low as 0.03 g cm(-3) and plastic/brittle behavior depending on the nanofiber aspect ratio. Conductivity measurements reveal a semiconducting behavior (10(-12) to 10(-7) S cm(-1) at 298 K) that can be improved by doping (10(-5) S cm(-1)). Moreover, it must be stressed that conductivity of MOAs reversibly increases (up to 10(-5) S cm(-1)) under the presence of acetic acid.