A Benzodiphosphaborolediide.

The first example of a diphosphaborolediide, the benzo-fused [C6 H4 P2 BPh]2- (12- ), is prepared from ortho-bis(phosphino)benzene (C6 H4 {PH2 }) and dichlorophenylborane, via a sequential lithiation approach. The dilithio-salt can be obtained as an oligomeric THF solvate or discrete TMEDA adduct, both of which are fully characterized, including by X-ray diffraction. Alongside NICS calculations, data strongly suggest some aromaticity within 12- , which is further supported by preliminary coordination studies that demonstrate η5 -coordination to a zerovalent molybdenum center, as observed crystallographically for the oligomeric [{Mo(CO)3 (η5 -1)}{µ-η1 -Mo(CO)3 (TMEDA)}2 ] ⋅ [µ-Li(THF)][µ-Li(TMEDA)].