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

Abstract

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 (MII: 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.

Self‐Foaming Metal‐Organic Gels Based on Phytic Acid and Their Mechanical, Moldable, and Load‐Bearing Properties.

“…Self‐sustainability is the ability of gels to stand by itself and withstand change or deformation when acted upon by external forces [8,11,32,59,60] . To study the self‐sustaining and load‐bearing property of the foaming gel, PA−Fe‐1 : 4 gel was cut into cylinders with a diameter of 2.0 cm and a height of 1.4 cm, and coins were placed on its top in succession (Figure 8).…”

Macroscopic Ultralight Aerogel Monoliths of Imine‐based Covalent Organic Frameworks

“…Aerogels are extremely important for several applications, including heterogeneous catalysis, energy storage, sensors, pollutant capture, and gas storage [13, 14] . They are traditionally prepared from silica gels, [15] but also can be made from metal oxides, [16] organic polymers, [17] carbon‐based materials, [13] biopolymers, [18] even metal–organic frameworks, [19] and polyhedra [20] . However, to date, COF‐based aerogels have been fabricated only via encapsulation of COF particles into aerogels made from other materials, such as alginate and graphene oxide.…”

“…Another class of very interesting macroscopic hierarchically porous objects is aerogels,p orous materials with 3D hierarchical morphology and porosity,l ow densities,h igh surface areas,and high total pore volumes,all of which greatly facilitate mass transport of adsorbed molecules through their matrices.A erogels are extremely important for several applications,i ncluding heterogeneous catalysis,e nergy storage,sensors,pollutant capture,and gas storage. [13,14] They are traditionally prepared from silica gels, [15] but also can be made from metal oxides, [16] organic polymers, [17] carbon-based materials, [13] biopolymers, [18] even metal-organic frameworks, [19] and polyhedra. [20] However,t od ate,C OF-based aerogels have been fabricated only via encapsulation of COF particles into aerogels made from other materials,s uch as alginate and graphene oxide.F or instance,m onolithic alginate aerogels incorporating different COFs have been fabricated using af reeze-drying template approach.…”

Conductive NiMn-based bimetallic metal–organic gel nanosheets for supercapacitors

“…[13][14][15][16] Besides, the synergistic effect of electrostatic effect and cross-linking coordination in the reaction system induce gelation to produce pores in the mesopore range (2-50 nm) to support the migration and diffusion of chemical substances. 17 Therefore, the MOGs have fascinated numerous attention as the potential energy storage application materials. 18,19 However, obtaining metal organic gels with special functions (high stability, great conductivity and so on) are sometimes difficult as only the single metal component is used.…”