The reactions of SiHPh(NCH2PPh2)2C6H4-1,2 with a range of zerovalent group 10 reagents afford the homoleptic bimetallic complexes [M2{μ-κ3-Si,P,P'-SiPh(CH2PPh2)2C6H4}2] (M = Ni, Pd, Pt) in which the M-M bond is unsymmetrically bridged by two σ-silyl groups. The asymmetry of the M2Si2 core increases from Ni through Pd to Pt and is consistent with a bonding description in which one metal acts as an electron pair donor to a trigonal bipyramidal 'Z-type' silicon centre, reminsicent of semi-bridging coordination by CO, carbynes and boryl ligands.