Complex Formation and Rearrangement Reactions of the Phosphine Hydride Anions [OsH₃(PPh₃)₃]^- and [IrH₂(PPh₃)₃]^-

Abstract

OsH 4 (PPh 3 ) 3 ] (1) reacts with KH in THF in the presence of 18-crown-6 to form [K(THF)(18-crown-6)][OsH 3 (PPh 3 ) 3 ] (2), characterized by NMR spectroscopy and X-ray crystallography; cation-anion contact is achieved through three Os-H‚‚‚K moieties. In contrast, [IrH 3 (PPh 3 ) 3 ] (6) reacts with KH and 18crown-6 in THF with redistribution of ligands to produce the known bis-phosphine complex [K(18crown-6)][IrH 4 (PPh 3 ) 2 ] (7). This reaction has been followed by NMR spectroscopy, and [IrH 2 (PPh 3 ) 3 ]has been identified as a likely intermediate. K[OsH 3 (PPh 3 ) 3 ] (3) reacts with Bu n 3 SnCl to form the tinosmium complex [OsH 3 (SnBu n 3 )(PPh 3 ) 3 ] (8), characterized by NMR spectroscopy and X-ray crystallography. The molecule contains a seven-coordinate osmium center, which can be described approximately as a distorted fac-[OsH 3 (PPh 3 )] arrangement, with the SnBu n 3 moiety capping the OsH 3 face.

Ketone Hydrogenation with Iridium Complexes with “non N–H” Ligands: The Key Role of the Strong Base

“…It is therefore likely to correspond to the catalyst resting state. Note that 16 is isoelectronic with the [IrH 4 (PR 3 ) 2 ] − (R = i Pr, Ph) anions, , which were isolated and fully characterized as salts of crown-ether-stabilized alkali metals. , …”

“…Note that 16 is isoelectronic with the [IrH 4 (PR 3 ) 2 ] − (R = iPr, Ph) anions, 86,87 which were isolated and fully characterized as salts of crownether-stabilized alkali metals. 86,88 After obtaining preliminary indications of the likely identity of the most stable solution species from the above exploratory investigations, selected calculations were carried out on the full system in order to assess the importance of electronic and steric effects associated with the ligand simplification. The calculations were carried out using 1 Ph as ligand at the full quantum mechanical level.…”

Synthesis and Characterization of Osmium(IV) Polyhydride Complexes of Stoichiometry (C5Me5)OsH3(L). Crystal Structures of (C5Me5)OsH3(AsPh3) and (C5Me5)OsH3(PPh3)

“…The arene complexes exhibit quantum exchange couplings between the hydride resonances with 2 J HH values as large as 400 Hz; for example, 2 J HH is 219 Hz at 153 K and increases to 374 Hz at 173 K for the triphenylphosphine derivative [(C 6 H 6 )OsH 3 (PPh 3 )][BF 4 ]. Other classes of osmium(IV) trihydrides are known, some of which also exhibit quantum exchange coupling. − …”

“…Other classes of osmium(IV) trihydrides are known, some of which also exhibit quantum exchange coupling. [22][23][24][25][26][27][28][29][30][31][32][33][34][35] The presence of large 2 J HH couplings in (C 5 Me 5 )RuH 3 (PR 3 ) and [(C 6 H 6 )OsH 3 (PR 3 )][BF 4 ] complexes, but not in compounds 8-11, is consistent with the proposal that quantum exchange couplings decrease as the metal center becomes more electron rich (i.e., as the frontier molecular orbitals become higher in energy) and the classical hydride structures are relatively stabilized. 4,7,11,14 The osmium C 5 Me 5 complexes are more electron rich than the Ru C 5 Me 5 analogues owing to general trends involving second-row vs third-row metals, and are more electron rich than the Os arene compounds owing to the different donor properties of the ligand sets.…”

Iron, ruthenium and osmium

“…121 [OsH 4 (PPh 3 ) 3 ] reacts with KH in THF in the presence of 18-crown-6 to form [K(THF)(18-crown-6)] fac-[OsH 3 (PPh 3 ) 3 ]; K is bound to the three hydrides. K[OsH 3 (PPh 3 ) 3 ] reacts with Bu 3 n SnCl forming [OsH 3 (SnBu 3 n)(PPh 3 ) 3 ], where SnBu 3 n caps a face of the octahedron 122. [OsCl{NHQC(Ph)C 6 H 4 }(PPr 3 i ) 2 (H 2 )] is a compressed dihydrogen complex with hindered rotation about Os-P bonds at low temperatures 123.…”