CO2 Activation Using a Molecular Metal Oxo Anion


This invention has applications as a means of CO2 sequestration, where it acts as either a carbon sink or a carrier for storage and transport. Additionally, this invention can also be used to mediate CO2functionalization as part of processes to convert CO2 to commercially valuable chemicals such as formic acid and formaldehyde.

Problem Addressed

Carbon dioxide is an attractive feedstock for many chemical processes due to its low cost, low toxicity, and abundance. The complexity of metal oxides conventionally used to fix CO2 makes them difficult to study. The molybdate dianion is a low-cost and readily available alternative with a simpler structure. However, commercially available forms of this compound are insoluble in most organic solvents and does not react with CO2 under aqueous conditions. This invention describes a novel molybdate complex that readily reacts with CO2 at room temperature.


The molybdate complex described in this invention is formed in a single-step process from Ag2MoO4 and PPNCl. It has a structure of [PPN]2[MoO4] and is capable of binding up to 2 equivalents of CO2, giving rise to [PPN]2[MoO3(κ2-CO3)] and [PPN]2[MoO2(κ2-CO3)2]. The binding of the first equivalent of CO2 has been demonstrated to be stable up to 70 ℃ under a vacuum, while that of the second equivalent can be reversed even at low temperatures. This difference in stability is what allows this novel molybdate complex to be used when either reversible or irreversible CO2 binding is desired. 


  • Simple molecular structure allows study of reactivity
  • Exhibits both reversible and irreversible binding of CO2