A benzodiphosphaborolediide

The first example of a diphosphaborolediide, the benzo-fused [C 6 H 4 P 2 BPh] 2- ( 1 2- ), is prepared from ortho-bis(phosphino)benzene (C 6 H 4 {PH 2 }) 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 1 2- , which is further supported by preliminary coordination studies that demonstrate ? 5 -coordination to a zerovalent molybdenum center, as observed crystallographically for the oligomeric [{Mo(CO) 3 (? 5 - 1 )}{µ-? 1 -Mo(CO) 3 (TMEDA)} 2 ].[Li(THF)][Li(TMEDA)].