REACTIONS INVOLVING CHELATE RING-OPENING OR METAL-ION RELOCATION IN THE FORMATION OF LUMINESCENT COMPLEXES CONTAINING BOTH GOLD AND IRIDIUM

Treatment of Ir(CO)2Cl(p-toluidine) with 2 equiv of dpmp (bis(diphenylphosphinomethyl)phenylphosphine) and ammonium hexafluorophosphate yields ivory [Ir(dpmp)2CO] [PF6], 5, which an X-ray crystal structure shows to have a five-coordinate geometry with one six-membered and one four-membered chelate ring. This structure is compared with that of [Ir(dpma)2CO] [PF6], 3 (dpma is bis(diphenylphosphinomethyl)phenyiarsine), which is trigonal-bipyramidal with two six-membered chelate rings that span axial and equatorial coordination sites. Addition of 3 equivs of Me2SAuCl to 5 results in the formation of orange [Ir(CO)ClAu(AuCl)2(μ-dpmp)2][PF6], 6, which has a planar Ir(CO)Cl(P)2 unit connected to the trans, terminal phosphorus atoms of the dpmp ligands, an Au(I) ion bound to the two internal phosphorus atoms, and AuCl moieties attached to the remaining two terminal phosphorus atoms of the dpmp ligands. Complex 6 has a strong absorption at 454 nm and photoemissions at 568 and 660 nm. Treatment of 6 with KCN or 5 with KCN and Me2SAuCI results in the formation of centrosymmetric [Au2Ir(CN)2(μ-dpmp)2][PF6], 7, with a linear Au-Ir-Au chain. The conversion of 6 to 7 results not only in loss of a gold ion but also extensive rearrangement at the core to go from a T-shaped Au2AuIr unit to a linear AulrAu section. Complex 7 is intensely magenta (λmax(absorption) = 578 nm) with photoemission at 612 and 782 nm. © 1990, American Chemical Society. All rights reserved.