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

Abstract

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(H 2 )(H)(dppe) 2 ]BPh 4 or with trans- Os(H)(Br)(dppe) 2 in THF under Ar. They are characterized by 1 H and 31 P 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 HBF 4 ·Et 2 O leads to the formation of the very reactive hydride thiol complexes trans -[M(H)(HSPh)(dppe) 2 ]BF 4 (M = Ru ( 2Ru ), Os ( 2Os )). Analogous complexes to 1Os and 2Os with SC 6 H 4 -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(H 2 )(SAr)(dppe) 2 ] + . In the presence of excess acid the diprotonated complex trans -[Os(H 2 )(HSPh)(dppe) 2 ](BF 4 ) 2 ( 3Os ) is formed at 233 K where the T 1 (min) of the H 2 ligand at 400 MHz is ∼34 ms so that 0.98 ≤ d HH ≤ 1.24 Å. Under certain conditions the labile PhSH ligand of 3Os is substituted by water to give trans -[Os(H 2 )(OH 2 )(dppe) 2 ](BF 4 ) 2 ( 4Os ). The thiol complexes 2 react rapidly with H 2 (g) to give the complexes trans -[M(H 2 )H(dppe) 2 ]BF 4 ( 5Ru, 5Os ). Complexes 3Os and 4Os also react with H 2 to give 5Os . N 2 and O 2 (1 atm) displace the thiol in 2Os in CH 2 Cl 2 to produce trans -[Os(H)(L)(dppe) 2 ] + (L = η 1 -N 2 ( 6Os), η 2 -O 2 ( 7Os )). trans -[Os(H)(O 2 )(dppe) 2 ]OTf·3C 6 H 6 is characterized by X-ray diffraction.