Di-ortho-beryllated Carbodiphosphorane: A Compound with a Metal Carbon Double Bond to an Element of the s-Block

Double bonds have been realized fora wide variety of lements in the p -, d-, and f-blocks. However, no s-block metal complexes with a don hie bond have been identified. Here we report the synthesis and characterization of a di-ortho-beryllated carbodiphosphorane, which exhibits a double dative Be = C bond. This species shows an unprecedented bonding situation at the metal center, which was extensively analyzed by experimental and comPutational means