title: The substitution reaction of (CNC)Fe-2N₂ with CO.
abstract: The substitution mechanism of two N₂ ligands in (CNC)Fe-2N₂ replaced by CO was studied theoretically at the B3LYP/LACVP* level. Both SN1 and SN₂ mechanisms were considered. The calculated results for the gas phase suggested that: 1) in SN1 mechanism, N₂ elimination, which involves S₀-T₁ PESs crossing, is the rate control step for both substitution stages. The barrier heights are 9.7 kcal mol(-1) and 13.05 kcal mol(-1), respectively. 2) In SN2 mechanism, the calculated barrier heights on LS PES are respectively 13.7 and 19.83 kcal mol(-1) for the two substitution steps, but S₀-T₁ PESs crossing lowers the two barriers to 10.7 and 15.7 kcal mol(-1), respectively. 3) Inclusion of solvation effect of THF by PCM model, the relative energies of all the key species (including minima, transition states and S₀-T₁ crossing points) do not have great difference from their gas phase relative energies. Considering that for each substitution step, SN1 barrier heights is slightly smaller than SN2 barrier, SN1 mechanism seems to be slightly preferable to SN2 mechanism.
authors.affiliation: College of Chemistry and Chemical Engineering, Shanxi Datong University, Datong 037009, Shanxi Province, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Liu
authors.forename: Shuangshuang
authors.initials: S
authors.lastname: Liu
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang
mesh_terms: D002248:Carbon Monoxide / Q000737:chemistry*; D003198:Computer Simulation; D007501:Iron / Q000737:chemistry*; D008024:Ligands; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D017672:Nitrogen Compounds / Q000737:chemistry*; D044367:Phase Transition; D013816:Thermodynamics
chemical_list: D008024:Ligands; D017672:Nitrogen Compounds; D002248:Carbon Monoxide; D007501:Iron