Protonation Reactions of trans-M(H)(SPh)(dppe)2 (M = Ru, Os) to Give Thiol and Dihydrogen Complexes. X-ray Crystal Structure Determination of trans-Ru(H)(SPh)(dppe)2 and trans-[Os(H)(O2)(dppe)2](O3SCF3)

Article abstract of DOI:10.1021/ic971050g

The compounds trans-M(H)(SPh)(dppe)₂ (M = Ru (1Ru), Os (1Os); dppe = 1,2-bis(diphenylphosphino)ethane) are synthesized by reaction of NaSPh with trans-[Ru(H₂)(H)(dppe)₂]BPh₄ or with trans-Os(H)(Br)(dppe)₂ in THF under Ar. They are characterized by ¹H and ³¹P NMR, IR, FAB mass spectroscopy, elemental analyses, and cyclic voltammetry. The crystal structure determination of 1Ru verifies the trans, octahedral geometry, which is distorted by ring-ring interactions. The thiophenoxide ligand is coordinated to the metal in a bent configuration, with the phenyl ring sandwiched between two phenyl rings of one of the dppe ligands. The reaction of complexes 1 with 1 equiv of HBF₄·Et₂O leads to the formation of the very reactive hydride thiol complexes trans-[M(H)-(HSPh)(dppe)₂]BF₄ (M = Ru (2Ru), Os (2Os)). Analogous complexes to 1Os and 2Os with SC₆H₄-4-F instead of SPh are also described. In all cases there is no evidence for the existence of the tautomeric dihydrogen complex trans-[M(H₂)(SAr)(dppe)₂]⁺. In the presence of excess acid the diprotonated complex trans-[Os(H₂)(HSPh)-(dppe)₂](BF₄)₂ (3Os) is formed at 233 K where the T₁(min) of the H₂ ligand at 400 MHz is ～34 ms so that 0.98 ≤ d_HH ≤ 1.24 A?. Under certain conditions the labile PhSH ligand of 3Os is substituted by water to give trans-[Os(H₂)(OH₂)(dppe)₂](BF₄) ₂ (4Os). The thiol complexes 2 react rapidly with H₂(g) to give the complexes trans[M(H₂)H(dppe)₂]BF₄ (5Ru, 5Os). Complexes 3Os and 4Os also react with H₂ to give 5Os. N₂ and O₂ (1 atm) displace the thiol in 2Os in CH₂Cl₂ to produce trans-[Os(H)(L)(dppe)₂]⁺ (L = η¹-N₂ (6Os), η²-O₂, (7Os)). trans-[Os(H)(O₂)(dppe)₂]OTf·3C₆H ₆ is characterized by X-ray diffraction.