Systematic Heterodinuclear Complexes with MM′(μ-meppp) Centers That Tune the Properties of a Nesting Hydride (M = Ni, Pd, Pt; M′ = Rh, Ir; H2meppp = meso-1,3-Bis[(mercaptoethyl)phenylphosphino]propane)

Mononuclear complexes with a P2S2 ligand, [M(meppp)] (M = Ni (1a), Pd (1b), Pt (1c); H2meppp = meso-1,3-bis[(mercaptoethyl)phenylphosphino]propane), were treated with [M′Cp*Cl2]2 or [M′Cp*(NO3)2] (Cp* = η5-pentamethylcyclopentadienyl) to afford a series of bisthiolate-bridged MIIM′III heterodinuclear complexes, [M(μ-meppp)M′Cp*X]X′ (M = Ni, Pd, Pt; M′ = Rh, Ir; X = Cl, NO3; X′ = Cl, PF6, NO3). The nitrate complexes [M(μ-meppp)-M′Cp*(NO3)]NO3 (M′ = Rh ([4a–c]NO3), Ir ([5a–c]NO3); M = Ni (a), Pd (b), Pt (c)) further reacted with sodium formate in water or methanol to be transformed into bisthiolate- and hydride-bridged complexes, [M(μ-meppp)(μ-H)M′Cp*]NO3 (M′ = Rh ([6a–c]NO3), Ir ([8a–c]NO3); M = Ni (a), Pd (b), Pt (c)). Complexes [6a]NO3 (M = Ni, M′ = Rh) and [8a]NO3 (M = Ni, M′ = Ir) were characterized by X-ray analyses to reveal that a hydride is stabilized in a semibridging mode on the heterometal centers. In the PdIIRhIII ([6b]NO3) and PtIIRhIII ([6c]NO3) complexes, the hydrides were extremely unstable...