Spectroscopy and redox properties of the luminescent excited state of [Au2(dppm)2]2+ (dppm = Ph2PCH2PPh2)

The electronic absorption spectrum of [Au2(dppm)2]2+[dppm = bis(diphenylphosphino)methane] in acetonitrile exhibits an absorption band at 290 nm, attributable to a pσâ†�dσ* transition. A much weaker band in the region 300–370 nm is assigned to a pσâ†�dδ* transition. Excitation of [Au2(dppm)2]2+ in degassed acetonitrile at 310–390 nm at room temperature results in phosphorescence centred at 575 nm, which is most likely to be derived from the 3B1u[(dδ*)1(pσ)1] state. The phosphorescence of [Au2(dppm)2]2+* is found to be quenched by a number of electron acceptors and donors, as well as energy-transfer acceptors. The powerful reducing nature of [Au2(dppm)2]2+* is revealed by its excited-state redox potential E°[Au2(dppm)23+/2+*] of –1.6(1) V vs. a saturated sodium chloride calomel electrode (s.s.c.e.) which was determined through studies of quenching by a series of pyridinium acceptors.

[1]  M. Savas,et al.  Electronic absorption and MCD spectra for the binuclear three-coordinate gold(I) complex Au2(dmpm)32+ (dmpm = bis(dimethylphosphino)methane) , 1989 .

[2]  J. Fackler,et al.  Syntheses and crystal structures (No gold-hydrogen interactions) of gold phosphine luminescent complexes, [Au2(dppm)2][BH3CN]2 and [Au2(dppm)2(I)][Au(CN)2] and [Au2(dppm)2(S2CNEt2)][BH3CN] , 1989 .

[3]  J. Fackler,et al.  Luminescence and metal-metal interactions in binuclear gold(I) compounds , 1989 .

[4]  H. Gray,et al.  Photoreactions of organic halides, alcohols, and olefins with tetrakis(pyrophosphito)diplatinate(II) , 1989 .

[5]  R. Rogers,et al.  Crystal structures and solution electronic absorption and MCD spectra for perchlorate and halide salts of binuclear gold(I) complexes containing bridging Me2PCH2PMe2 (dmpm) or Me2PCH2CH2PMe2 (dmpe) ligands , 1989 .

[6]  H. Gray,et al.  Spectroscopic properties of binuclear palladium(0) and platinum(0) dibenzylideneacetone complexes , 1989 .

[7]  H. Gray,et al.  Pyrophosphito-bridged diplatinum chemistry , 1989 .

[8]  A. Balch,et al.  Nearly linear rhodium(I) aggregates. Chemical and spectroscopic behavior of [Rh3(CNCH3)6{.mu.-(Ph2PCH2)2PPH}2]3+ and its oxidation products , 1988 .

[9]  Suning Wang,et al.  Synthesis and characterization of the luminescent dithiolate-bridged dimer [n-Bu4N]2[Au(i-MNT)]2 (i-MNT=S2C2(CN)22−) and its structurally characterized, metal-metal-bonded gold(II) oxidation product [Ph4As]2[Au(i-MNT)Cl]2 , 1988 .

[10]  H. Gray,et al.  Low-lying singlet and triplet electronic excited states of binuclear (d10-d10) palladium(0) and platinum(0) complexes , 1988 .

[11]  H. Gray,et al.  Binuclear platinum(II) photochemistry. Rates of hydrogen atom transfer from organometallic hydrides to electronically excited Pt2(P2O5H2)44 , 1987 .

[12]  M. Savas,et al.  Electronic and MCD spectra of linear two-coordinate dihalo-, halo(trialkylphosphine)-, and bis(triethylphosphine)gold(I) complexes , 1987 .

[13]  H. Gray,et al.  Picosecond spectroscopic studies of (d8-d8) binuclear rhodium and iridium complexes: a comparison of 1B2 and 3B2 reactivity in bis(1,5-cyclooctadiene)bis(.mu.-pyrazolyl)diiridium(I). , 1986, Journal of the American Chemical Society.

[14]  J. Caspar.  Long-lived reactive excited states of zero-valent phosphine, phosphite, and arsine complexes of nickel, palladium and platinum , 1985 .

[15]  D. Roundhill.  Excited-state chemistry of tetrakis(.mu.-pyrophosphito)diplatinum(II). Photoinduced addition of aryl bromides and iodides to the binuclear complex and the photoinduced catalytic conversion of isopropyl alcohol into acetone and hydrogen , 1985 .

[16]  K. Kalyanasundaram,et al.  Energy- and electron-transfer processes of the lowest triplet excited state of tetrakis(diphosphito)diplatinate(II) , 1985 .

[17]  T. Meyer,et al.  Photochemistry of Metal-Metal Bonds , 1985 .

[18]  H. Gray,et al.  Spectroscopy and photochemistry of binuclear iridium(I) complexes , 1984 .

[19]  S. F. Rice,et al.  Photophysical properties of the lowest electronic excited states of binuclear rhodium(I) isocyanide complexes , 1982 .

[20]  H. Gray,et al.  Spectroscopic properties and redox chemistry of the phosphorescent excited state of octahydrotetrakis(phosphorus pentoxide)diplatinate(4-) ion (Pt2(P2O5)4H84-) , 1981 .

[21]  E. Kosower,et al.  1-Alkyl-2-(carbomethoxy)pyridinyl radicals: monomers and dimers defined through chemical and photochemical properties and electron paramagnetic resonance , 1981 .

[22]  R. A. Goldbeck,et al.  Studies of energy-transfer and electron-transfer processes involving the 3A2u excited states of binuclear rhodium isocyanide complexes , 1980 .

[23]  B. P. Sullivan,et al.  Application of electron-transfer theory to excited-state redox processes , 1979 .

[24]  U. Schubert,et al.  Gold‐Komplexe von Diphosphinomethanen, II. Synthese und Kristallstruktur achtgliedriger Ringverbindungen von Gold(I) mit Au–Au‐Wechselwirkung , 1977 .

[25]  W. Mason.  Metal to ligand charge-transfer spectra in tetra-n-butylammonium dicyanoaurate(I) , 1976 .

[26]  J. Demas,et al.  Measurement of photoluminescence quantum yields. Review , 1971 .

[27]  J. Cotter,et al.  Stable Free Radicals. II. The Reduction of 1-Methyl-4-cyanopyridinium Ion to Methylviologen Cation Radical , 1964 .

[28]  W. Simpson,et al.  Spectroscopic Study of Wurster's Blue and Tetramethyl-p-phenylenediamine with Assignments of Electronic Transitions1 , 1955 .