Synthesis of porous coordination polymers using carbon dioxide as a direct source

Carbon fixation of CO2 via cyclic reactions with borane in gaseous atmosphere leading to formic acid (and metaboric acid); A potential energy surface (PES) study

Carbon dioxide (CO₂), a stable gaseous species, occupies the troposphere layer of the atmosphere. Following it, the environment gets warmer, and the ecosystem changes as a consequence of disrupting the natural order of our life. Due to this, in the present reasearch, the possibility of carbon fixation of CO₂ by using borane was investigated. To conduct this, each of the probable reaction channels between borane and CO₂ was investigated to find the fate of this species. The results indicate that among all the channels, the least energetic path for the reaction is reactant complex (RC) to TS (A-1) to Int (A-1) to TS (A-D) to formic acid (and further meta boric acid production from the transformation of boric acid). It shows that use of gaseous borane might lead to controlling these dangerous greenhouse gases which are threatening the present form of life on Earth, our beautiful, fragile home.

One-Pot, Room-Temperature Conversion of CO2 into Porous Metal-Organic Frameworks

The conversion of CO₂ into functional materials under ambient conditions is a major challenge to realize a carbon-neutral society. Metal-organic frameworks (MOFs) have been extensively studied as designable porous materials. Despite the fact that CO₂ is an attractive renewable resource, the synthesis of MOFs from CO₂ remains unexplored. Chemical inertness of CO₂ has hampered its conversion into typical MOF linkers such as carboxylates without high energy reactants and/or harsh conditions. Here, we present a one-pot conversion of CO₂ into highly porous crystalline MOFs at ambient temperature and pressure. Cubic [Zn₄O(piperazine dicarbamate)₃] is synthesized via in situ formation of bridging dicarbamate linkers from piperazines and CO₂ and shows high surface areas (∼2366 m² g^-1) and CO₂ contents (>30 wt %). Whereas the dicarbamate linkers are thermodynamically unstable by themselves and readily release CO₂, the formation of an extended coordination network in the MOF lattices stabilizes the linker enough to demonstrate stable permanent porosity.

Reactivity of borohydride incorporated in coordination polymers toward carbon dioxide

Borohydride (BH₄^-)-containing coordination polymers converted CO₂ into HCO₂^- or [BH₃(OCHO)]^-, whose reaction routes were affected by the electronegativity of metal ions and the coordination mode of BH₄^-. The reactions were investigated using thermal gravimetric analysis under CO₂ gas flow, infrared spectroscopy, and NMR experiments.