Photoreactivity of gold complexes

Vogler, Arnd

doi:10.1016/s0010-8545(01)00348-4

Cited by 157 publications

(134 citation statements)

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“…The presence of a nonemissive low-lying d-d state would quench the luminescence excited state by thermal equilibration or energy transfer. [7] Coupling of strong sdonating alkynyl ligands to gold(iii) should render the metal center more electron rich, with the additional advantage of raising the energy of the d-d states, which would result in enhanced luminescence by increasing the chances of populating the emissive state for the construction of luminescent organometallic materials. Despite the fact that alkynyl complexes of gold(i) [3] and the isoelectronic platinum(ii) [5] are known and have been shown to display rich photoluminescence properties, to our surprise, alkynyl complexes of gold(iii) are extremely rare.…”

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confidence: 99%

Luminescent Gold(III) Alkynyl Complexes: Synthesis, Structural Characterization, and Luminescence Properties

et al. 2005

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In contrast to the related gold(i) [1][2][3] and the isoelectronic platinum(ii) compounds, [4,5] which are known to show rich luminescence properties, luminescent gold(iii) compounds are rare, with very few exceptions that emit at room temperature in solution.[6] The reasons for the lack of luminescence in gold(iii) species are probably the presence of low-energy d-d ligand field (LF) states and the electrophilicity of the gold(iii) center. The presence of a nonemissive low-lying d-d state would quench the luminescence excited state by thermal equilibration or energy transfer.[7] Coupling of strong sdonating alkynyl ligands to gold(iii) should render the metal center more electron rich, with the additional advantage of raising the energy of the d-d states, which would result in enhanced luminescence by increasing the chances of populating the emissive state for the construction of luminescent organometallic materials. Despite the fact that alkynyl complexes of gold(i) [3] and the isoelectronic platinum(ii) [5] are known and have been shown to display rich photoluminescence properties, to our surprise, alkynyl complexes of gold(iii) are extremely rare.[8] Although there is increasing interest in the use of gold(iii) compounds for catalysis of organic synthetic reactions of alkynes, [9] the chemistry of gold(iii) alkynyls is essentially unexplored and underdeveloped, and their luminescence properties are virtually unknown.Herein we describe the synthesis of a novel series of biscyclometalated gold(iii) alkynyl complexes [Au(C^N^C)-(C CR)] [HC^N^CH = 2,6-diphenylpyridine, R = C 6 H 5 (1), C 6 H 4 -Cl-p (2), C 6 H 4 -OCH 3 -p (3), C 6 H 4 -NH 2 -p (4); HC^N^CH = 2,6-bis(4-tert-butylphenyl)pyridine, R = C 6 H 5 (5)], which are the first of their kind (Scheme 1). The molecular structure of 1 was determined by X-ray crystallography. The photophysical properties of 1-5 were also studied.Unlike most other gold(iii) compounds, which exhibit luminescence only at low temperature or are nonemissive, complexes 1-5 display luminescence in various media at both low and ambient temperature. Figure 1 shows the crystal structure of 1, in which the gold(iii) center adopts a distorted square-planar coordination geometry with C (9)

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confidence: 99%

Luminescent Gold(III) Alkynyl Complexes: Synthesis, Structural Characterization, and Luminescence Properties

et al. 2005

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“…Au(III) [33] localized in HAuCl 4 at 315 nm cannot be observed due to overlapping with the other bands. It is not possible either to detect any reduction to Au(I), as there is no absorption at 246 nm [34]. The molar extinction coefficient for the lowest energy peak is 401 in case of azpy (450 nm) and 741 in case of Au-azpy (440 nm).…”

Section: Electronic Spectramentioning

confidence: 99%

“…Several factors involved in the chemical transformation of Au-azpy were considered, such as the influence of solvent, temperature, the presence of dioxygen and also the influence of light, as light sensitivity of Au(III) complexes is well known [34].…”

Section: Stability Studiesmentioning

confidence: 99%

“…It is well known that organometallics containing metal-ligand r bonds are characterized by long-wavelength LMCT absorptions [34]; however, these are not observed in the corresponding electronic spectra. The ill-defined nature of other products formed during the synthesis of pyrium has precluded electron accounting and possible elucidation of the reaction stoichiometry and mechanistic proposal.…”

Section: Crystallographymentioning

confidence: 99%

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The synthesis, chemical and biological properties of dichlorido(azpy)gold(III) chloride (azpy= 2-(phenylazo)pyridine) and the gold-induced conversion of the azpy ligand to the chloride of the novel tricyclic pyrido[2,1-c][1,2,4]benzotriazin-11-ium cation

Garza-Ortiz

Dulk

Brouwer

et al. 2007

Journal of Inorganic Biochemistry

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The synthesis, chemical and biological properties of dichlorido(azpy)gold(III) chloride (azpy = 2-(phenylazo)pyridine) and the gold-induced conversion of the azpy ligand to the chloride of the novel tricyclic pyrido [2,1-c] AbstractA new Au(III) coordination compound with the ligand 2-(phenylazo)pyridine has been synthesized and fully characterized by means of elemental analysis, IR, UV-visible, conductivity measurements, NMR, electrospray ionization (ESI-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES). The chemical stability of the cation in this compound, [Au(azpy)Cl 2 ] + (abbreviated: Au-azpy), was analyzed by means of several physicochemical methods. While stable in the solid state, stability studies performed with the gold compound in solution showed an unexpected and unprecedented reactivity. A cationic organic derivative of 2-(phenylazo)pyridine, (abbreviated: pyrium), was produced from the solution and has been isolated as its chloride salt and characterized by crystal structure determination, elemental analysis, NMR, ESI-MS and conductivity studies in solution. This cyclization reaction is reported for the first time in the case of gold coordination compounds.The Au adduct and the pyrium cation were investigated as potential cytotoxic and anticancer agents, and both show moderate to high cytotoxic properties in cisplatin-sensitive and cisplatin-resistant ovarian carcinoma cell lines, A2780; and cisplatin-sensitive and cisplatinresistant murine lymphocytic leukemia cell lines, L1210. Significant anticancer activity against the cisplatin resistant cell lines was found for the pyrium salt, ruling out the occurrence of cross resistance phenomena.

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“…(59). The light sensitivity of some gold compounds has permitted the study of an important number of photochemical reactions (60).…”

Section: Box 10 Ring and Catenane Gold(i) Complexesmentioning

confidence: 99%

Some recent highlights in gold chemistry

Gimeno

Laguna

2003

Gold Bull

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Photoreactivity of gold complexes

Cited by 157 publications

References 42 publications

Luminescent Gold(III) Alkynyl Complexes: Synthesis, Structural Characterization, and Luminescence Properties

Luminescent Gold(III) Alkynyl Complexes: Synthesis, Structural Characterization, and Luminescence Properties

The synthesis, chemical and biological properties of dichlorido(azpy)gold(III) chloride (azpy= 2-(phenylazo)pyridine) and the gold-induced conversion of the azpy ligand to the chloride of the novel tricyclic pyrido[2,1-c][1,2,4]benzotriazin-11-ium cation

Some recent highlights in gold chemistry

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