80462-14-2Relevant academic research and scientific papers
Binuclear 'Oxidative Isomerization' as a Model for Surface Reactions. Intramolecular Character and Kinetic Profile of Iodomethyldi-iridium(II): μ-Methylenedi-iridium(III) Conversion that follows Di-iodomethane Addition to2 (Hpz=pyrazole)
Brost, Ron D.,Stobart, Stephen R.
, p. 498 - 500 (1989)
Isomerization of di-iridium(II) complex (2, Hpz=pyrazole) to the di-iridium(III) methylene complex (7) which occurs on reflux in benzene solution has been found to be intramolecular by mass spectrometric analysis of isotope distribution (13C and 2H) in isotopomers of (7) formed from (2) containing 13CO or C2H2I groups or both, and the (2)-(7) conversion shows first-order behaviour which is conspicuously retarded by added PPh3; an X-ray crystal structure determination for compound (7) confirms that the two Ir centres lie outside bonding range at 3.432(1) Angstroem with tetrahedral μ-CH2.
Pyrazolyl-bridged iridium dimers. 6. Two-fragment, two-center oxidative addition of halogens and methyl halides to trans-bis(triphenylphosphine)dicarbonylbis(μ-pyrazolyl)diiridium(I)
Atwood, Jerry L.,Beveridge, Kathy A.,Bushnell, Gordon W.,Dixon, Keith R.,Eadie, Donald T.,Stobart, Stephen R.,Zaworotko, Michael J.
, p. 4050 - 4057 (2008/10/08)
Reaction between trans-lr(PPh3)2(CO)Cl and Na(pz) (pzH = C3N2H4, pyrazole) affords the scarlet diiridium complex [Ir(PPh3)(CO)(μ-pz)]2 (1a) characterized by single-crystal X-ray crystallography, in which the terminal PPh3 and CO ligands are mutually trans across the Ir2 axis with a formally nonbonded Ir2 separation of 3.163 (2) A?; the latter is somewhat longer [3.290 (1) A?] in the orange-red hexane solvate (1b). A systematic synthesis of the same compound is described, in which reaction of [Ir(COD)Cl]2 with pzH giving the dimer [Ir(COD)(μ-pz)]2 (2) is followed by treatment with CO and PPh3 to provide 1 in 82% yield. Reaction of 1 with Ir2 and Br2 leads to formation of yellow complexes formulated as 1-1 adducts formed by a two-center oxidative addition, i.e. [Ir(PPh3)(CO)(X)(μpz)]2 (X = I, Br); with Cl2 the corresponding product has been characterized crystallographically as [Ir(PPh3)(CO)(Cl)(4-Cl-pz)]2 (9) in which the trans configuration of 1 is retained Axial substitution at each Ir with Ir-Cl = 2.443 (6) A? has been accompanied by formation of a metal-metal bond [Ir-Ir = 2 737 (1) A?] and electrophilic substitution by Cl of the 4-position in each bridging pyrazolyl-ring system. Reaction between 1 and Mel affords a yellow 1:1 adduct (80% yield) for which a corresponding dimeric structure is proposed having Me attached to Ir(1) and I to Ir(2); by contrast with MeBr, reaction is slower to give an unidentified mixture of products. Crystals of 1a are triclinic, space group P1: a = 9.992 (4), b = 10.402 (4), c = 20.278 (8) A?; β = 90.01 (4), β = 90.10 (4), γ = 105.13 (4)°. Modification 1b crystallizes in P21/c: a = 15.528 (4), b = 9.713 (3), c = 30.544 (8) A?; β = 93.98 (2)°. For the addition product (9), the space group is P21/n: a = 15.851 (3), b = 28.617 (4), c = 11.092 (2) A?; β = 95.82 (2)°.
