Synthesis and x-ray structure of the tetranuclear butterfly iridium cluster Ir4(CO)8L[.mu.3-.eta.3-Ph2PC(H)CPh](.mu.-PPh2) (L = PCy3) and carbon-13, proton, and 13C{1H}, 1H, and 31P{1H} NMR studies of the compounds with L = CO, PCy3, and P(OMe)3, [carbon monoxide, tricyclohexylphosphine, and trimethyl phosphite]

Carbon–carbon coupling on tetrahedral iridium clusters: X-ray molecular structures and multinuclear NMR studies of the two isomeric forms of [Ir4(CO)6(μ3-η2-HCCPh)(μ2-η4-C4H2Ph2)(μ-PPh2)2]

“…When carried out at 25°C for 24 h or at 40°C for 4 h, in toluene or in CH 2 Cl 2 , with one equiv. of HC"CPh, formation of [Ir 4 (CO) 8 (l 3 -g 2 -HCCPh)(l-PPh 2 ) 2 ] (2) exclusively was observed, as the result of the decarbonylation and rearrangement of 1 [27]. When the reaction mixture was heated at 80°C in toluene for 4 h with two equiv.…”

“…doi:10.1016/j.jorganchem.2004.08.010 this tetranuclear cluster under thermolytic conditions with C 2 (COOMe) 2 , to yield [Ir 4 (CO) 8 {C 2 (COOMe) 2 } 4 ] [22], and with cod (cod = cyclooctadiene), to give the alkyne containing clusters [Ir 4 (CO) 5 (cod) 2 (C 8 H 10 )] and [Ir 7 -(CO) 12 (cod)(C 8 H 11 )(C 8 H 10 )] [23,24] all in very low yields, and that of the oxidation of [Ir 6 (CO) 15 ] 2À with ferrocinium in the presence of PhCCPh to yield [Ir 6 -(CO) 14 (l 3 -g 2 -HCCPh)] and [Ir 6 (CO) 12 (l 3 -g 2 -HCCPh) 2 ] [25]. The cluster [HIr 4 (CO) 10 (l-PPh 2 )] [26] has proven itself a good entry into tetranuclear iridium organometallic chemistry [27][28][29][30][31][32][33][34][35]. Its derivative [HIr 4 -(CO) 9 (Ph 2 PC"CPh)(l-PPh 2 )] (1) undergoes a selective rearrangement under mild conditions to give [Ir 4 -(CO) 8 (l 3 -g 2 -HCCPh)(l-PPh 2 ) 2 ] (2) [34].…”

Synthesis and Structural Characterisation of [Ir4(CO)8(CH3)(mu4-eta3-Ph2PCCPh)(mu-PPh2)] and of the Carbonylation Product [Ir4(CO)8{C(O)CH3}(mu4-eta3-Ph2PCCPh)(mu-PPh2)]; First Evidence for the Formation of a CO Cluster Adduct before CO Insertion

“…SCHAKAL92 21 was used for the graphical representation of the results. ] (30%) were also isolated, probably due to the presence of moisture in the reaction mixture, and identified by IR and NMR spectroscopies 8 . Compound 2 was characterised by a combination of IR spectroscopy, satisfactory microanalysis (see Experimental), FAB MS and 1 H, 13 C{ 1 H} and 31 P{ 1 H} NMR spectroscopies (see Table 1).…”

“…This observation would explain the scarcity of alkyl carbonyl clusters in the literature. We recently reported the synthesis 8 and the molecular structure 9 of the only other Ir 4 cluster with a terminal hydride ligand, [HIr 4 (CO) 9 (µ 4 -η 3 -Ph 2 PCCPh)(µ-PPh 2 )], via the deprotonation of [(µ-H)-Ir 4 (CO) 10 (µ-PPh 2 )], reaction in situ with Ph 2 PC≡CPh, followed by reprotonation. We therefore attempted to produce the analogous methyl containing cluster, by methylating, instead of protonating, the mixture above.…”

Oxidative Addition Reactions of I2 with [HIr4(CO)10-n(PPh3 )n(μ-PPh2)] (n = 1 and 2) and Crystal and Molecular Structure of [HIr4(μ-I)2(CO)7 (PPh3)(μ-PPh2)]

“…1 Our recent studies indicate that these derivatives behave differently from 1 in the presence of molecules or fragments that may undergo oxidative addition. For example, although 1 does not react with alkynes and alkenes, 2 phosphines containing unsaturated fragments, such as Ph 2 PC≡CPh, can interact further with 1 to yield µ 4 -η 3 -Ph 2 PCCPh containing species and products resulting from P-C bond activation, 3,4 further hydrometallation 5 or P-C bond formation. 6 Furthermore, we have found that oxidative addition of the PhP(CPh) 2 ring is extremely sensitive to the metal frame electronic density and can be delicately tuned by the presence of PPh 3 .…”