Struktur und Koordinationsverhalten des sterisch anspruchsvollen Phenylcycloarsoxans

Structure and Coordination Chemistry of Sterically Demanding Phenylcycloarsoxane Tetrameric phenylcycloarsoxane (C₆H₅AsO)₄ 1 exhibits a boat‐chair‐conformation in the solid state. Its reaction with CuI in benzonitrile leads to the formation of coordination polymers. [(CuI · C₆H₅CN){cyclo‐(C₆H₅AsO)₄}] ( 2 ) underlines the structure‐directing steric requirements of the phenyl side chains. Treatment of 1 with M(CO)₆ (M = Cr, Mo) confirms its capability to undergo metal‐mediated ring expansion. In [{M(CO)₃}₂{cyclo‐(C₆H₅AsO)₆}] with M = Cr ( 3 ) and M = Mo ( 4 ), twelve membered As–O‐rings are stabilised by the participation of alternating As atoms in the coordination spheres of opposite facial transition metal carbonyl fragments M(CO)₃.