Executive Summary : | While the individual areas of FeS cluster and iron porphyrins are extensively investigated, the possibilities of new chemistry that can arise of FeS cluster Iron porphyrin conjugates lie completely unexplored. The low valent chemistry of the active site of sufite reductases (SiRs) which reduce SO2 (environmental waste) by 6e to H2S and nitrite reductases (NiRs) which reduce NOx (environmental waste) by 6e to NH3 provide ample motivation to undertake such a project. Not only are these active sites responsible for recycling toxic NOx and SOx pollutants but also invoke unprecedented chemical entities, detailed in the main text) in their reaction cycles most of which lie in the realm of theoretical explorations. The synthesis and assembly of FeS cluster is difficult but reasonably well-established. However, the approach developed by Holm and co-workers relies on terminal thiols. With the exception of the LS3 ligand from TDP Stack, there has been no exploration of chelating ligands aiding the assembly of these structures. The approach proposed here does just that. The prophyrins proposed provide a. A multiple-thiolate anchor needed for the assembly of different FeS clusters. b. The ability to change the length of the thiol arm to allow flexibility to the FeS cluster binding cavity. c. A very reactive center in the form of iron porphyrin which we have shown to be able to reduce O2, NO2, SO2, CO2 and, CO. Apart from the obvious lure of the challenge involved in completing this work, lies the possibility of exploring a less realized domain of inorganic chemistry ÃÂâÃÂÃÂÃÂàredox gating of selectivity in multiple electron processes. Simply put can one stop the reduction of NO2- to NO or N2O or NH2OH by controlling the potential of the electron transfer site? The possibility to control the selectivity of chemical steps that require multiple electrons by controlling the number of electrons stored in an inorganic moiety is rather exciting - albeit its realization is daunting. |