864653-70-3

Downstream Products

• 864513-33-7 [RhIr(CH3)2(μ-CO)(μ-Ph2PCH2PPh2)2] 
• 135708-03-1 {RhIrI₂(CO)(CO)((C₆H₅)2PCH₂P(C₆H₅)2)2} 

Relevant academic research and scientific papers

Models for multicenter catalysts. 3. Facile hydride rearrangements in A-frame and related complexes and the structure of [RhIr(H)2(CO)2(μ-Cl)(DPM)2][BF 4]·CH2Cl2, the product of H2 addition at one metal center in the A-frame pocket

The reactions of several binuclear diiridium and heterobinuclear rhodium/iridium complexes with H2 are discussed. The compounds [RhIr(CO)2(μ-X)(DPM)2]n+ (X = Cl, n = 1; X = S, n = 0; DPM = bis(diphenylphosphino)methane) react with H2 to give dihydrides in which the hydrido ligands are shown by NMR spectroscopy to be primarily bound to the iridium center with one hydrido ligand in each case also interacting weakly with the rhodium atom. The X-ray structure determination of [RhIr(H)2- (CO)2(μ-Cl)(DPM)2][BF4] supports this bonding proposal. These mixed-metal species model key intermediates in the hydride rearrangements observed in the related homobinuclear diiridium complexes [Ir2(CO)2(μ-X)(DPM)2]n+ (X = Cl, n = 1; X = S, n = 0), and a mechanism for these hydride rearrangements is proposed. Of these A-frame complexes only [Ir2(CO)2(μ-Cl)-(DPM)2][BF4] reacts further with excess H2, yielding two isomeric tetrahydrides. The complex [Ir2(CO)2(μ-I)(DPM)2][BF4] reacts somewhat differently with H2 than do the related sulfido- and chloro-bridged A-frames, leading to a dihydride that does not undergo rearrangement. This dihydride reacts further with H2, yielding only one tetrahydride species, which readily reductively eliminates HI to give the known trihydride [Ir2H(CO)2(μ-H)2(DPM)2] +. The neutral complex [RhIrCl2(CO)2(DPM)2] reacts with H2, yielding a cationic dihydride identical with that of its A-frame counterpart. The neutral iodide [Ir2I2(CO)2(DPM)2] also reacts with H2 to give a cationic dihydride analogous to that observed when H2 is reacted with [Ir2(CO)2(μ-I)(DPM)2] [BF4] but rapidly interconverts at room temperature with the neutral dihydride [Ir2(H)2I2(CO)2(DPM)2] which has one hydrido ligand on each metai, mutually adjacent to one another. These hydrido ligands are chemically inequivalent with one being trans to a carbonyl group while the other is opposite an iodo ligand. The structure of [RhIr(H)2(CO)2(μ-Cl)(DPM)2] [BF4]·CH2Cl2 has been determined by X-ray crystallography. It crystallizes in the triclinic space group P1 with a = 14.171 (2) A?, b = 22.638 (3) A?, c = 9.642 (2) A?, α = 94.18 (1)°, β = 107.38 (2)°, γ = 105.84 (1)°, V = 2799.4 A?,3, and Z = 2. Refinement has converged to R =.0.053 and Rw = 0.081 based on 7935 unique observations and 364 parameters varied. This binuclear, DPM-bridged complex has a slightly distorted square planar Rh(I) center and an octahedral Ir(III) center, the latter of which has both hydrido ligands attached. These hydrido ligands are bound in the inside pocket of the complex with one being in a position to interact weakly with the Rh atom.