Reactivity of [{Cp'Fe(μ-I)}(2)] toward 3-phospha- and 3-arsaethynolate.

[{Cp'Fe(μ-I)}(2)] (I; Cp' = η(5)-1,2,4-(Me(3)C)(3)C(5)H(2)) reacts with [Na(OCP)(1,4-dioxane)(x)] and K(OCAs) to yield [(Cp'Fe)(2)(μ-η(2):η(2)-P(2))(μ-CO)] (1) and [(Cp'Fe)(2)(μ-η(2):η(2)-As(2))(μ-CO)] (3), respectively. While complex 1 was previously accessed by Scherer and co-workers using rather harsh reaction conditions, the new synthetic method already proceeds at ambient temperature. UV-light irradiation of 1 and 3 induces CO release forming complexes [(Cp'Fe)(2)(μ-η(2):η(2)-E(2))] (E = P (2) and As (4)), respectively. However, both reactions also yielded several byproducts which were spectroscopically identified. Furthermore, upon thermally triggered CO elimination from 3 the Fe(3)As(6)-cluster [(Cp'Fe)(3)(As(3))(2)] (5) is isolated in low yield. In addition, zero-field (57)Fe Mössbauer spectra were recorded on complexes 1-4 and computational studies complement the experimental findings and provide additional insights into the bonding in these complexes and the reaction pathways resulting in the formation of complexes 1-4.