Unexpected differences in the reactivity between the phosphorus and arsenic derivatives [(Cp BIG Fe) 2 (μ,η 4:4 -E 4 )] (E = P and As)

Different reaction pathways were determined between thermolysis and photolysis reactions of the butterfly complex [{Cp Fe(CO) } (μ,η -As )] (1b). The thermolysis leads to novel arsenic-rich compounds [(Cp Fe) (μ,η -As )] (2b), [(Cp Fe) (μ ,η -As )] (4) and [Cp Fe(η -As )] (5), whereas the photolysis of [{Cp Fe(CO) } (μ,η -E )] (1a: E = P; 1b: E = As) exclusively results in the decarbonylation products [(Cp Fe) (μ,η -P )] (2a), 2b and [(Cp Fe)(μ,η -As )(Cp Fe(CO) )] (3). The E complexes 2a and 2b show unique structural differences in the solid state despite their related compositions.