15842-08-7Relevant academic research and scientific papers
Selective hydroboration of equilibrating allylic azides
Liu, Ruzhang,Xu, Jun,Zhang, Yuanyuan
supporting information, p. 8913 - 8916 (2021/09/13)
The iridium(i)-catalyzed hydroboration of equilibrating allylic azides is reported to provide only the anti-Markovnikov product of alk-1-ene isomers in good yields and with good functional group tolerance.
Reactions of organic halides with the carbonyl anions [M(CO)4]- (M = Rh, Ir). Crystal and molecular structure of [PPN][IrBr2(CO)2(CH2CO2Me) 2] and of [PPN][Ir(CO)2(CH<
Porta, Francesca,Ragaini, Fabio,Cenini, Sergio,Demartin, Francesco
, p. 929 - 935 (2008/10/08)
By reaction of [PPN][Ir(CO)4] (1, PPN = [(Ph3P)2N+]) with BrCH2R (R = CO2Me, CN, Ph), the anionic derivatives, all cis-[PPN][IrBr2(CO)2(CH2R)2] [
FORMATION OF CARBON-CARBON BONDS ON DI(ORGANO)IRIDIUM COMPLEXES, RR'Ir(CO)(PPH3)2X (R,R' = Me, Ph, CH2Ph, C(O)CH3; X = Cl, I) AND THE CRYSTAL STRUCTURE OF cis,cis,trans-
Churchill, Melvyn Rowen,Fettinger, James C.,Janik, Thomas S.,Rees, Wayne M.,Thompson, Jeffrey S.,et al.
, p. 233 - 246 (2007/10/02)
The reactions of RX with trans-R'Ir(CO)(PPh3)2 are reported.Addition of CH3C(O)Cl to trans-CH3Ir(CO)(PPh3)2 leads to acetone; addition of CH3I to trans-PhIr(CO)(PPh3)2 leads to toluene; and addition of CH3I to trans-C6H5CH2Ir(CO)(PPh3)2 leads to ethylbenzene.Reaction of C2H5Br with trans-CH3Ir(CO)(PPh3)2 leads to CH4 and C2H4.The addition of CH3I to trans-CH3Ir(CO)(PPh3)2 leads to Ir(CH3)2Ir(CO)(PPh3)2I from which Ir(CH3)2(CO)2(PPh3)2(1+) and Ir(CH3)2(CO)(PPh3)2(1+) can be prepared.These dimethyl complexes do not undergo reductive elimination of ethane, acetone or diacetyl under a variety of conditions (CH4 and C2H6 are formed at decomposition).Thus for these complexes the charge, the presence of a free coordination site and the cis stereochemistry do not facilitate reductive elimination reactions.To ascertain that no structural features were preventing reductive elimination from the dimethyl complex we have examined the structure of cis,cis,trans-.This crystallizes in the centrosymmetric triclinic space group P (C1i; No. 2) with a 11.708(2), b 11.738(2), c 14.702(2) Angstroem, α 87.544(13), β 79.181(14), γ 76.963(15)deg, V 1933.4(6) Angstroem3 and D(calc'd) 1.64 g cm-3 for mol. wt. 951.9 and Z = 2.X-ray diffraction data (Mo-Kα, 2θ 4.5-50.0deg) were collected with a Syntex P21 automated four-circle diffractometer and the structure was refined to R 3.5percent for all 6835 reflections (R 2.9percent for those 6133 reflections with F0 > 6?(F0)).The central d6 iridium(III) ion has a slightly distorted octahedral stereochemistry, with Ir-CO 1.943(5) and 1.956(5) Angstroem, Ir-CH3 2.152(5) and 2.155(5) Angstroem and Ir-PPh3 2.391(1) and 2.400(1) Angstroem; interligand angles include OC-Ir-CO 102.09(20), CH3-Ir-CH3 89.70(19) and PPh3-Ir-PPh3 174.68(4)deg.
Stereoselective Oxidative Addition of Hydrogen to Iridium(I) Complexes. Kinetic Control Based on Ligand Electronic Effects
Johnson, Curtis E.,Eisenberg, Richard
, p. 3148 - 3160 (2007/10/02)
The oxidative addition of H2 to the iridium(I) chelates IrX(CO)(dppe)(n+) (n=0; X=Cl, Br, I, CN, H; n=1, X=PPh3; dppe=1,2-bis(diphenylphosphino)ethane) proceeds with >99percent stereoselectivity to yield a cis-dihydride product with one hydride trans to P(dppe) and the other hydride trans to CO.For X=Cl, Br, and I, the kinetic product of formula IrH2X(CO)(dppe) equilibrates with a more stable cis isomer which has one hydride trans to P and the other trans to X (Keq=41, 35, and 13, respectively).The stereochemical assignments based on chemical shifts of the hydride ligands are confirmed by single crystal X-ray diffraction analysis of the thermodynamic isomer for X=Br.The complex IrH2Br(CO)(dppe) crystallizes in the orthorhombic space group P212121 with unit cell parameters a=12.291(3) Angstroem, b=17.349(4) Angstroem, c=12.189(3) Angstroem, V=2599 Angstroem3, and Z=4.The structure refined to a conventional R factor of 0.035.The isomerization reaction between the two dihydride isomers has been studied mechanistically in acetone and benzene solvents.In acetone, the isomerization of IrH2Br(CO)(dppe) proceeds with first-order kinetics in iridium complex (k=0.011 min-1), and the mechanism likely involves a two-step H2 reductive elimination/oxidative addition process.For X=CN, the kinetic dihydride isomer is the most stable isomer, but it does thermally equilibrate with two other isomers.For X=H, or PPh3, only a single isomer is observed and it appears to be the most stable isomer.The stereoselectivity of D2 oxidative addition for X=H is established by generating the reactive species IrH(CO)(dppe) in situ by dehydrohalogenation of IrH2Cl(CO)(dppe) under D2.For all of the complexes studied, the stereochemistry of hydrogen oxidative addition is the same, and the observed stereoselectivity is dictated by electronic differences between CO and X ligands.Possible explanations for the observed stereoselectivity are discussed in relation to current theories on the intimate mechanism of H2 oxidative addition.
