12115-50-3Relevant academic research and scientific papers
The cyclooctadiene ligand in [IrCl(COD)]2is hydrogenated under transfer hydrogenation conditions: A study in the presence of PPh3and a strong base in isopropanol
Rahaman,Daran, Jean-Claude,Manoury, Eric,Poli, Rinaldo
, p. 14 - 21 (2017)
The interaction of [IrCl(COD)]2with PPh3in isopropanol has been investigated for various P/Ir ratios, in the absence or presence of a strong base (KOtBu), at room temperature and at reflux. At room temperature, PPh3adds to
Cooperative double deprotonation of bis(2-picolyl)amine leading to unexpected bimetallic mixed valence (M-I, MI) rhodium and iridium complexes
Tejel, Cristina,Del Rio, M. Pilar,Asensio, Laura,Van Den Bruele, Fieke J.,Ciriano, Miguel A.,Tsichlis I Spithas, Nearchos,Hetterscheid, Dennis G. H.,De Bruin, Bas
, p. 7524 - 7534 (2011)
Cooperative reductive double deprotonation of the complex [Rh I(bpa)(cod)]+ ([4]+, bpa = PyCH 2NHCH2Py) with one molar equivalent of base produces the bimetallic species [(cod)Rh(bpa-2H)Rh(cod)] (7), which displays a large Rh -I,RhI contribution to its electronic structure. The doubly deprotonated ligand in 7 hosts the two "Rh(cod)" fragments in two distinct compartments: a "square planar compartment" consisting of one of the Py donors and the central nitrogen donor and a "tetrahedral π-imine compartment" consisting of the other pyridine and an "imine C=N" donor. The formation of an "imine donor" in this process is the result of substantial electron transfer from the {bpa-2H}2- ligand to one of the rhodium centers to form the neutral imine ligand bpi (bpi = PyCH2N=CHPy). Hence, deprotonation of [RhI(bpa)(cod)] + represents a reductive process, effectively leading to a reduction of the metal oxidation state from RhI to Rh-I. The dinuclear iridium counterpart, complex 8, can also be prepared, but it is unstable in the presence of 1 mol equiv of the free bpa ligand, leading to quantitative formation of the neutral amido mononuclear compound [Ir I(bpa-H)(cod)] (2). All attempts to prepare the rhodium analog of 2 failed and led to the spontaneous formation of 7. The thermodynamic differences are readily explained by a lower stability of the M-I oxidation state for iridium as compared to rhodium. The observed reductive double deprotonation leads to the formation of unusual structures and unexpected reactivity, which underlines the general importance of "redox noninnocent ligands" and their substantial effect on the electronic structure of transition metals.
Developing synthetic approaches with non-innocent metalloligands: Easy access to IrI/Pd0 and IrI/Pd 0/IrI cores
Tejel, Cristina,Asensio, Laura,Del Rio, M. Pilar,De Bruin, Bas,Lopez, Jose A.,Ciriano, Miguel A.
, p. 8839 - 8843 (2011)
Guilty as charged is the verdict for anionic Ir complex [Ir(bpa-2 H)(cod)]- in its reactions with PdII compounds. The net transfer of two electrons from the Ir complex to Pd allows easy preparation of di- and trinuclear π-imine-coordinated Pd0 compounds such as [{Ir(PyCH2NCHPy)(cod)}2Pd] (see picture; C white, Ir red, N blue, Pd yellow). bpa-2 H: doubly deprotonated form of N,N-bis(2-picolyl)amine (bpa); cod: 1,5-cyclooctadiene.
Experimental and theoretical mechanistic investigation of the iridium-catalyzed dehydrogenative decarbonylation of primary alcohols
Olsen, Esben P. K.,Singh, Thishana,Harris, Pernille,Andersson, Pher G.,Madsen, Robert
, p. 834 - 842 (2015/01/30)
The mechanism for the iridium-BINAP catalyzed dehydrogenative decarbonylation of primary alcohols with the liberation of molecular hydrogen and carbon monoxide was studied experimentally and computationally. The reaction takes place by tandem catalysis through two catalytic cycles involving dehydrogenation of the alcohol and decarbonylation of the resulting aldehyde. The square planar complex IrCl(CO)(rac-BINAP) was isolated from the reaction between [Ir(cod)Cl]2, rac-BINAP, and benzyl alcohol. The complex was catalytically active and applied in the study of the individual steps in the catalytic cycles. One carbon monoxide ligand was shown to remain coordinated to iridium throughout the reaction, and release of carbon monoxide was suggested to occur from a dicarbonyl complex. IrH2Cl(CO)(rac-BINAP) was also synthesized and detected in the dehydrogenation of benzyl alcohol. In the same experiment, IrHCl2(CO)(rac-BINAP) was detected from the release of HCl in the dehydrogenation and subsequent reaction with IrCl(CO)(rac-BINAP). This indicated a substitution of chloride with the alcohol to form a square planar iridium alkoxo complex that could undergo a β-hydride elimination. A KIE of 1.0 was determined for the decarbonylation and 1.42 for the overall reaction. Electron rich benzyl alcohols were converted faster than electron poor alcohols, but no electronic effect was found when comparing aldehydes of different electronic character. The lack of electronic and kinetic isotope effects implies a rate-determining phosphine dissociation for the decarbonylation of aldehydes.
Slow exchange of bidentate ligands between rhodium(I) complexes: Evidence of both neutral and anionic ligand exchange
Chen, Si,Manoury, Eric,Poli, Rinaldo
supporting information, p. 5820 - 5826 (2015/02/19)
The phosphine double exchange process involving [RhCl(COD)(TPP)] and [Rh(acac)(CO)(TMOPP)] (TPP = PPh3, TMOPP = P(C6H4-4-OMe)3) to yield [RhCl(COD)(TMOPP)] and [Rh(acac)(CO)(TPP)] is very rapid but is followed by a much slower process where the bidentate ligands are exchanged to yield [Rh(acac)(COD)] and a mixture of [RhCl(CO)(TPP)2], [RhCl(CO)(TMOPP)2], and [RhCl(CO)(TPP)(TMOPP)]. The exchange involving [RhCl(COD)(L)] and [Rh(acac)(CO)(L)] yields [Rh(acac)(COD)] and [RhCl(CO)(L)2], where the reaction is much faster when L = TPP than when L = TMOPP. The mixed-metal system comprising [IrCl(COD)(TPP)] and [Rh(acac)(CO)(TPP)] yields all four complexes [M(acac)(COD)] and [MCl(CO)(TPP)2], where M = Rh and Ir. This illustrates that both a neutral ligand exchange and an anionic ligand exchange occur. Possible pathways for these processes are discussed.
