186391-07-1

Upstream product

• 67969-82-8 tetrafluoroboric acid diethyl ether 
• 762-42-5 dimethyl acetylenedicarboxylate 
• 186391-09-3 [Ir2(H)(CO)2(μ-η(1):η(1)-dimethyl acetylenedicarboxylate)(bis(diphenylphosphino)methane)2][BF4] 
• 201230-82-2 carbon monoxide 
• 97487-41-7 [Ir₂(CO)3(bis(diphenylphosphino)methane)2] 
• 186390-93-2 [Ir2(CO)2(μ-η(1):η(1)-dimethyl acetylenedicarboxylate)(bis(diphenylphosphino)methane)2] 

Relevant academic research and scientific papers

Alkyne or alkene binding versus hydrogenation in reactions with [Ir2H(CO)2(μ-H)2(Ph2PCH 2PPh2)2] [BF4]. Structure of [Ir2(C2H4)(CO)2(μ-H)(Ph 2PCH2PPh2)2] [BF4]

The reactions of [Ir2H(CO)2(μ-H)2(dppm)2] [BF4] (1) (dppm = Ph2PCH2PPh2) with the alkynes, dimethyl acetylenedicarboxylate, hexafluoro-2-butyne or acetylene yield the respective products [Ir2(H)2(CO)2(μ-H)(μ-RCCR)(dppm) 2] [BF4] (R = CO2Me, CF3, H) in which the alkyne bridges the metals, bound in a parallel orientation. With tetrafluoroethylene the analogous olefin-bridged product [Ir2(H)2(CO)2(μ-H)(μ-C2F 4)(dppm)2] [BF4] is obtained. The reactions of 1 with diphenylacetylene or ethylene result in hydrogenation, to yield cis-stilbene and ethane, respectively, with subsequent reaction of the resulting unsaturated intermediate with additional substrate to give [Ir2(CO)2(μ-H)(μ-PhCCPh)(dppm)2] [BF4] or [Ir2(C2H4)(CO)2(μ-H)(dppm) 2] [BF4]. In the diphenylacetylene adduct this group is bound in a parallel position bridging the metals whereas the ethylene ligand binds to one metal in a terminal position opposite the Ir-Ir bond. The structure of this ethylene adduct has been determined by X-ray crystallography. This compound crystallizes in the monoclinic space group P21/n, having a = 13.6872(7), b = 15.459(2), c = 23.813(2) A?, β = 97.870(5)° and Z = 4. The carbonyl and ethylene ligands are disordered, but their positions have been adequately resolved and the structure has refined (on F2) to R1(F0) = 0.0344 (observed data) for 8699 unique reflections (6638 observations) and 653 parameters varied.

Parallel vs. perpendicular alkyne coordination in binuclear complexes. The first examples of reactivity differences in isomers differing in their alkyne coordination modes

The reaction of [Ir2(CO)3(dppm)2] (dppm = Ph2PCH2PPh2) with dimethyl acetylenedicarboxylate (DMAD) first yields [Ir2(CO)2(μ-η1:η 1-DMAD)(dppm)2] (2) in which the alkyne is bound parallel to the metal-metal axis and the diphosphines are bound in a trans arrangement at both metals. This metastable isomer slowly rearranges to the stable form, [Ir2(CO)2(μ-η2:η 2-DMAD)(dppm)2] (3), in which the alkyne is now bound perpendicular to the metals and the diphosphines are bent back in a cis arrangement at both metals. The analogous species can be prepared by substituting hexafluoro-2-butyne (HFB) for DMAD; however, for the HFB adduct the isomer having the parallel geometry is seen only as a transient species; only [Ir2(CO)2(μ-η2:η 2-HFB)(dppm)2] (5) was isolated. Compound 2 reacts readily with PMe3 to yield [Ir2(CO)(PMe3)(μ-CO)(μ-η1:η 1-DMAD)(dPPm)2], and with CH3OSO2CF3 to yield [Ir2(CH3)(CO)2(μ-η 1:η1-DMAD)(dppm)2][SO3CF 3], whereas 3 reacts with neither reagent. Both 2 and 3 react with HBF4·OEt2 to yield the respective alkyne-bridged hydrides, [Ir2H(CO)2(μ-η1:η 1-DMAD)(dppm)2][BF4] and [Ir2H(CO)2(μ-η2:η 2-DMAD)(dppm)2][BF4], in which the gross structural features and the alkyne coordination mode of the precursor are retained in each case. The latter species rearranges readily at ambient temperature, via migratory insertion, to give the vinyl-bridged product, [Ir2(CO)2(μ-η1:η2-RC = C(H)R)(dppm)2][BF4] (R = CO2Me); however, the former is inert under these conditions, yielding the above vinyl species together with other decomposition products only upon reflux in benzene for several hours. Protonation of the perpendicular hexafluoro-2-butyne adduct also yields the corresponding vinyl product, together with decomposition products. The structure of 3, as the methylene chloride disolvate, was established by X-ray analysis. Crystal data are as follows. 3·2CH2Cl2: C60H54Cl4O6P4Ir 2, monoclinic, P2/c, a = 26.088(5) A, b = 9.896(4) A, c = 23.954(3) A, β = 109.27(1)°, Z = 4, R(F) = 0.038, Rw(F2) = 0.0997 (all data).