TY - JOUR
T1 - Pyrazolyl-bridged iridium dimers. 6.1 two-fragment, two-center oxidative addition of halogens and methyl halides to trans-bis(triphenylphosphine)dicarbonylbis(ju-pyrazolyl)diiridium(I)
AU - Atwood, Jerry L.
AU - Stobart, Stephen R.
AU - Zaworotko, Michael J.
AU - Beveridge, Kathy A.
AU - Bushnell, Gordon W.
AU - Dixon, Keith R.
AU - Eadie, Donald T.
AU - Stobart, Stephen R.
PY - 1984/1
Y1 - 1984/1
N2 - Reaction between trans-Ir(PPh3)2(CO)Cl and Na(pz) (pzH = C3N2H4, pyrazole) affords the scarlet diiridium complex [Ir(PPh3)(CO)(μ-pz)]2 (la) 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) Å; the latter is somewhat longer [3.290 (1) Å] in the orange-red hexane solvate (lb). 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)(μ-pz)]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) Å has been accompanied by formation of a metal-metal bond [Ir-Ir = 2.737 (1) Å] 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 structureis proposed having Me attached to Ir(l) and I to Ir(2); by contrast with MeBr, reaction is slower to give an unidentified mixture of products. Crystals of la are triclinic, space group PI: a = 9.992 (4), b = 10.402 (4), c = 20.278 (8) Å; α = 90.01 (4), β = 90.10 (4), γ = 105.13 (4)°. Modification lb crystallizes in P21/c: a = 15.528 (4), b = 9.713 (3), c = 30.544 (8) Å; 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) Å β = 95.82 (2)°.
AB - Reaction between trans-Ir(PPh3)2(CO)Cl and Na(pz) (pzH = C3N2H4, pyrazole) affords the scarlet diiridium complex [Ir(PPh3)(CO)(μ-pz)]2 (la) 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) Å; the latter is somewhat longer [3.290 (1) Å] in the orange-red hexane solvate (lb). 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)(μ-pz)]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) Å has been accompanied by formation of a metal-metal bond [Ir-Ir = 2.737 (1) Å] 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 structureis proposed having Me attached to Ir(l) and I to Ir(2); by contrast with MeBr, reaction is slower to give an unidentified mixture of products. Crystals of la are triclinic, space group PI: a = 9.992 (4), b = 10.402 (4), c = 20.278 (8) Å; α = 90.01 (4), β = 90.10 (4), γ = 105.13 (4)°. Modification lb crystallizes in P21/c: a = 15.528 (4), b = 9.713 (3), c = 30.544 (8) Å; 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) Å β = 95.82 (2)°.
UR - http://www.scopus.com/inward/record.url?scp=0000068698&partnerID=8YFLogxK
U2 - 10.1021/ic00192a042
DO - 10.1021/ic00192a042
M3 - Article
AN - SCOPUS:0000068698
SN - 0020-1669
VL - 23
SP - 4050
EP - 4057
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 24
ER -