New Main-Group-Element-Rich nido-Octahedral Cluster System: Synthesis and Characterization of [Et4N][Fe2(CO)6(µ3-As){µ3-EFe(CO)4}2].

A series of clusters of the form [Et4N][Fe2(CO)6(µ3-As)}(µ3-EFe(CO)4)], where E is either P or As, were synthesized from [Et4N]2[HAs{Fe(CO)4}3] and ECl3. AsCl3 gives the As-only compound; PCl3 produces compounds having two As atoms with one P atom, or one As atom and two P atoms, and they can exist as two possible isomers, one of which is chiral. The As2P and AsP2 clusters cocrystallize, and their structure as determined by single-crystal X-ray diffraction is given along with the structure of the As-only cluster. Analytical data as well as density functional theory calculations support the formation and geometries of the new molecules.