III Tetrafluoroborates

DIHYDRIDOBIS(SOLVENT)BIS(TRIPHENYL-PHOSPHINE)IRIDIUM(III) TETRAFLUOROBORATES 

Submitted by ROBERT H. CRABTREE, MICHELLE F. MELLEA, and JEAN 

Complexes between organometallic or metal hydride complexes and hard bases have attracted attention recently.1 In many cases the reaction solvent plays the role of a Lev is base such complexes can be catalytically active by solvent ligand dissociation.2,3 We describe here the complexes [IrH2S2(PPh3)2][BF4], where S = Me2CO,4,5 H20,5 or S2 = o- 

Several of the syntheses described in this chapter start from the well-known [Ir(cod)(PPh3)2][BF4], (cod = 1,5-cyclooctadiene), which can easily be obtained,4 10 from the commercially available [Ir(cod)Cl]2 (Strem.). 

Our own synthesis is a modification of the ones that have been described but in which we use Ag[BF4] to abstract chloride ion, this prevents the formation of Ir(cod)Cl(PPh3) as a side product. 

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Preparation by oxidising tris(phenanthroline)cobalt(III) tetrafluoroborate with nitric acid in sulfuric acid with potassium bromide catalysis is potentially explosive. See Nitric acid... 

Dihydridobis(Solvent)Bis( Triphenyl-Phosphine)Iridium(III) Tetrafluoroborates 125... 

D. (1,2-DIIODOBENZENE)DIHYDRIDOBIS(TRIPHENYL-PHOSPHINE)IRIDIUM(III) TETRAFLUOROBORATE(l -)... 

Cyclopentadienylbenzeneiridium(III) tetrafluoroborate [7T-C5H5)Ir(7r-C6Hg)](BF4)2 (complex 1.12) was completely inactive in oxidation with hydrogen peroxide and ferf-butyl hydroperoxide but exhibited a moderate activity in oxidation with m-chloroperoxybenzoic acid at room temperature [15b]. The H2O2-I.12 system showed a moderate activity in the oxidation of secondary alcohols. For example, cyclohexanol was oxidized at room temperature to cyclohexanone (30% yield for 6 h) when a fourfold excess of PCA as a cocatalyst was added to the reaction solution. 

C22H30MO2N2O3S6 0.25 C3H6O, M Oxo-di-M-thiophenolato-bis(N,N-di-ethyldithiocarbamato-oxo-molybdenum acetone solvate, 43B, 1205 C22H40BF4N4O2RU2S8, M Bis(N,N-diethyldithiocarbamato)-bis(N,N-diethyldithi ocarbamato)dicarbonyldiruthenium( 11, III) tetrafluoroborate, 46B, 999... 

C2aHii8N4S82n2, Zinc hexamethylenedithiocarbamate dimer, 38B, 870 C28H53N2PPtSft CgHi2 r Bis(N t-butyIdithiocarbamato)(tricyclohexyl-phosphine )platinum( 11) cyclohexane solvate, 45B, 1093 C2 8H5 6BF4N5ORU2S10 f Bis(N,N-diethyldithiocarbamato)-M tris(N,N-di-ethyldithiocarbamato)diruthenium(III) tetrafluoroborate acetone solvate, 42B, 775... 

In the case of ( )-phenylvinyl(aryl)iodine(III) tetrafluoroborates 36, nucleophilic substitution can occur via a at least two pathways. The reaction of 36 with acetic acid proceeds to give a mixture of ( )- and (Z)- acetates 37 and 38 with the retention of configuration product 37 being the major product (Scheme 25). 

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