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

[{Cp'Fe(mu-I)}2] (I; Cp' = eta 5-1,2,4-(Me3C)3C5H2) reacts with [Na(OCP)(1,4-dioxane)x] and K(OCAs) to yield [(Cp'Fe)2(mu-eta 2:eta 2-P2)(mu-CO)] (1) and [(Cp'Fe)2(mu-eta 2:eta 2-As2)(mu-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(mu-eta 2:eta 2-E2)] (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 Fe3As6-cluster [(Cp'Fe)3(As3)2] (5) is isolated in low yield. In addition, zero-field 57Fe M & ouml;ssbauer 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.