Novel Photophysical Properties of Gold Selenide Complexes:  Photogeneration of Singlet Oxygen by [Au₁₈Se₈(dppe)₆]Br₂and Near-Infrared Photoluminescence of [Au₁₀Se₄(dpppe)₄]Br₂

Abstract

The photoluminescence (PL) properties of several recently synthesized ligand-stabilized polynuclear gold(I) selenide complexes were investigated. [Au18Se8(dppe)6]Br2 {dppe = bis(diphenylphosphanyl) ethane} (I) is distinguished by the bright-red long-lived PL (phosphorescence) in the solid state, photosensitization of singlet oxygen, 1O2, in solution, and high photostability. The quantum yield of PL, φPL, is (7.5 ± 0.5) × 10-2 for the polycrystalline I at 293 K (determined using an integrating sphere) and increases up to ∼0.8 at 77 K. The quantum yield of 1O2 is 0.17 ± 0.02 in O2-saturated dichloromethane solutions. [Au10Se4(dpppe)4]Br2 {dpppe = bis(diphenylphosphanyl)pentane} (II) shows a broad near-infrared PL at 880 nm in dichloromethane [φPL = (4 ± 1) × 10-3], which is shifted up to ∼1020 nm in the solid II at 77 K (φPL ∼ 3 × 10-3). Although the quantum efficiency of II as a luminophor is quite moderate, it is comparable to that of organic infrared laser dyes such as Styryl-20 and IR26. A particular configuration of the Au10Se4 core appears to be crucial for the near-infrared PL: the “isomeric” complexes [Au10Se4(dppm)4]Br2 {dppm = bis(diphenylphosphanyl) methane} (III) and [Au10Se4(depe)4]Cl2 {depe = bis(diethylphosphanyl) ethane} (IV) show no significant PL.

Microwave‐Assisted Synthesis of Luminescent LaPO4:Ce,Tb Nanocrystals in Ionic Liquids

“…The quantum yield of the dispersion (f PL-LaPO4 , l exc = 273 nm) was determined relative to the quantum yield of Coumarin 307 in methanol (f PL-Coumarin = 0.95(2), l exc = 273 nm) with a similar optical density. [16] Received: January 19, 2006 Revised: April 6, 2006 . Keywords: colloids · ionic liquids · luminescence · microwaves · synthetic methods …”

Photophysics of Individual Single-Walled Carbon Nanotubes

“…148 The absorption and fluorescence spectra for IR-26, as well as its chemical structure, are shown in Figure 3 HiPco and CoMoCAT samples were calculated using eq 2-39. structures in this starting material. 86 HiPco SWNTs have a diameter distribution of 0.62- 86 CoMoCAT nanotubes are naturally enriched in (6,5) and (7,5) SWNTs; based on fractional fluorescence intensities, each of these structures comprises ~28% of the semiconducting species, for a combined total of ~38% of all CoMoCAT structures.…”

Visible photoluminescence from nearly monodispersed Au12 clusters protected by meso-2,3-dimercaptosuccinic acid

“…The charge state of gold atoms in clusters 1 and 2 is formally expressed as Au(0) rather than Au(I) based on the absence of the counter ion Cl À as confirmed by an EDX elemental analysis and the Au(4f) electron binding energy determined by XPS measurements. Thus, clusters 1 and 2 are categorized into the family of gold MPCs, although their properties are similar in many aspects to gold(I) thiolate complexes [15][16][17][18]. Clusters 1 are formulated as Au 12 (DMSA) 7 on the basis of these examinations.…”