Tetra-Au(I) Complexes Bearing a Pyrene Tetraalkynyl Connector Behave as Fluorescence Torches

Gutiérrez‐Blanco, Ana; Fernández‐Moreira, Vanesa; Gimeno, M. Concepción; Peris, Eduardo; Poyatos, Macarena

doi:10.1021/acs.organomet.8b00217

Cited by 15 publications

(11 citation statements)

References 42 publications

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“…The Au−C and C≡C distances and P‐Au‐C and Au‐C≡C angles (Table 1) are in the usual ranges for Au I alkynyl complexes [28, 31–41] . Linear coordination of the phenanthrene ligands at the Au I centers is observed, with P‐Au‐C angles of 172.6–179.0°.…”

Section: Resultsmentioning

confidence: 84%

Effect of Gold(I) on the Room‐Temperature Phosphorescence of Ethynylphenanthrene

Aquino

Caparrós

Aullón

et al. 2020

Chemistry A European J

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The synthesis of two series of gold(I) complexes with the general formulae PR3‐Au‐C≡C‐phenanthrene (PR3=PPh3 (1 a/2 a), PMe3 (1 b/2 b), PNaph3 (1 c/2 c)) or (diphos)(Au‐C≡C‐phenanthrene)2 (diphos=1,1‐bis(diphenylphosphino)methane, dppm (1 d/2 d), 1,4‐bis(diphenylphosphino)butane, dppb (1 e/2 e)) has been realized. The two series differ in the position of the alkynyl substituent on the phenanthrene chromophore, being at the 9‐position (9‐ethynylphenanthrene) for the L1 series and at the 2‐position (2‐ethynylphenanthrene) for the L2 series. The compounds have been fully characterized by 1H, 31P NMR, and IR spectroscopy, mass spectrometry, and single‐crystal X‐ray diffraction resolution in the case of compounds 1 a, 1 e, 2 a, and 2 c. The emissive properties of the uncoordinated ligands and corresponding complexes have been studied in solution and within organic matrixes of different polarity (polymethylmethacrylate and Zeonex). Room‐temperature phosphorescence (RTP) is observed for all gold(I) complexes whereas only fluorescence can be detected for the pure organic chromophore. In particular, the L2 series presents better luminescent properties regarding the intensity of emission, quantum yields, and RTP effect. Additionally, although the inclusion of all the compounds in organic matrixes induces an enhancement of the observed RTP owing to the decrease in non‐radiative deactivation, only the L2 series completely suppresses the fluorescence, giving rise to pure phosphorescent materials.

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Section: Resultsmentioning

confidence: 84%

Effect of Gold(I) on the Room‐Temperature Phosphorescence of Ethynylphenanthrene

Aquino

Caparrós

Aullón

et al. 2020

Chemistry A European J

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“…Therefore, of primary importance to the understanding of this relationship is the knowledge of the lifetimes, quantum yields, and rate constants for the all the deactivation processes. Only a few reports have been found to analyze the excited-state dynamics giving important information such as the effect of the organic chromophore and the nature of the bonding to the gold atom in the resulting very large intersystem crossing rate constants, , or the inclusion of a heteroatom to confer a strong intramolecular charge transfer character to the transitions as a possible reason for the close proximity of the k ISC and k IC values. , In fact, the presence of gold(I), as heavy atom, does not necessarily ensure a fast intersystem crossing rate, and the nature of the ligands also plays an important role in the excited-state dynamics and deactivation mechanisms. − Conversely, in the case of moderate intersystem crossing rate constant values, comparable with that of fluorescence deactivation, room temperature fluorescence/phosphorescence dual emission can be observed for this sort of gold compounds. , Additionally, the electronic properties of the ancillary alkynyl substituents were shown to affect significantly the rate of the ISC process by means of altering the contribution of charge transfer transitions and therefore to influence the probability of singlet vs triplet emission …”

Section: Introductionmentioning

confidence: 99%

Comprehensive Investigation of the Photophysical Properties of Alkynylcoumarin Gold(I) Complexes

et al. 2021

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Six gold(I) complexes (R 3 P-Au-Coum) containing three different alkynylcoumarin chromophores (Coum) with different electron-donating and electron-withdrawing characteristics and two different water-soluble phosphanes (PR 3 = PTA (a) and DAPTA (b)) have been synthesized (1a,b, unsubstituted coumarin; 2a,b, 4-methyl substituted coumarin; 3a,b, 3-chloro and 4-methyl substituted coumarin). A comprehensive study of the photophysical properties of the R 3 P-Au-Coum, together with their propynyloxycoumarin precursors 1−3, was performed in solution at room and low temperatures. Spectral and photophysical characteristics of the R 3 P-Au-Coum essentially depend on the electronic characteristics of the propynyloxycoumarin ligand. The presence of the Au(I) atom was found to be responsible for an increase of the intersystem crossing, with triplet state quantum yield values, ϕ T , ranging from ∼0.05 to 0.35 and high coumarin phosphorescence quantum yield values for derivatives 1 and 2; fluorescence dominates the deactivation in derivatives 3. Efficient singlet oxygen photosensitization was observed for the new compounds 3a,b. From TDDFT calculations, the relevant HOMO and LUMO of the compounds, i.e., those involved in the transitions, are dominated by the frontier orbitals associated with the coumarin core. The Au(I)-phosphane structure introduces a new transition assigned to an intraligand transition involving the phosphane ligand, and π(CC) system, to the p orbitals of phosphorus and gold atoms.

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“…10 More recently, we prepared a tetra-Au(I) complex connected by 1,3,6,8-tetraethynylpyrene, which turned out to be one of the most efficient Au-based fluorescence emitters in solution reported to date (C, Chart 1). 11 All of these findings illustrate how pyrene-adorned NHCmetal complexes constitute an interesting family of materials with unusual photophysical and catalytic properties. In this new work, we report the preparation of a pyrene-connected tetra-imidazolium salt and its use as tetra-NHC precursor in the preparation of rhodium and iridium complexes.…”

Section: ■ Introductionmentioning

confidence: 76%

Pyrene-Connected Tetraimidazolylidene Complexes of Iridium and Rhodium. Structural Features and Catalytic Applications

2018

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A pyrene-connected tetra-imidazolium salt has been prepared starting from commercially available 1,3,6,8-tetrabromopyrene, and used as tetra-NHC precursor in the preparation of tetranuclear Rh(I) and Ir(I) complexes. The tetra-NHC ligand displays axial chirality upon coordination to the MCl(cod) (M = Rh and Ir) fragments, giving rise to right- and left-handed helix conformations. The catalytic activity of the resulting complexes was studied in two relevant reactions that lead to the formation of five- and six-membered oxygen-containing heterocycles, namely, the cyclization of acetylenic carboxylic acid and the coupling of diphenylcyclopropenone with substituted phenylacetylenes.

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Tetra-Au(I) Complexes Bearing a Pyrene Tetraalkynyl Connector Behave as Fluorescence Torches

Cited by 15 publications

References 42 publications

Effect of Gold(I) on the Room‐Temperature Phosphorescence of Ethynylphenanthrene

Effect of Gold(I) on the Room‐Temperature Phosphorescence of Ethynylphenanthrene

Comprehensive Investigation of the Photophysical Properties of Alkynylcoumarin Gold(I) Complexes

Pyrene-Connected Tetraimidazolylidene Complexes of Iridium and Rhodium. Structural Features and Catalytic Applications

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