Three- and Four-Coordinate Gold(I) Complexes

Gimeno, M. Concepción; Laguna, Antonio

doi:10.1021/cr960361q

Cited by 238 publications

(176 citation statements)

References 117 publications

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“…structures or extended polymeric chains [1][2][3][4]. Gold(I) monohalide dimers that have very short Au···Au distances are probably the ultimate examples of relativistic effects on molecular structure [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…Theoretical studies have shown that the aurophilic interaction is the result of correlation effects that are enhanced by relativistic effects [7,8]. The aurophilic interactions between the closed-shell Au(I) centres are important in determining the solid state structures of many gold(I) compounds and contribute to the chemical and physical properties of these complexes [1][2][3][4][9][10][11][12][13]. The distance between two interacting gold atoms in compounds showing aurophilic interactions is less than 3.6 Å.…”

Section: Introductionmentioning

confidence: 99%

“…In these systems, the luminescence changes is usually associated with the alteration of non-covalent interactions or originate from molecular conformation changes. Recently, we reported some cationic gold(I)-diphosphine [Au 2 (diphos) 2 ] 2+ complexes (diphos = diphosphine) with short intramolecular aurophilic interaction that exhibit reversible stimuli-responsive luminescence behaviour [21][22][23]. The stimuli-responsive dinuclear [Au 2 (xantphos) 2 ](NO 3 ) 2 complex (xantphos = 9,9'-dimethyl-4,5-bis(diphenylphosphino)-xanthene) exhibits reversible switching between crystalline and amorphous phases having distinctly different emission properties [21].…”

Section: Introductionmentioning

confidence: 99%

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Structural characterization of dinuclear gold(I) diphosphine complexes with anion-triggered luminescence

et al. 2015

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Structural characterization of dinuclear gold(I) diphosphine complexes with anion-triggered luminescence

et al. 2015

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“…Gold(I) complexes most commonly exist as two-coordinate (AuL 2 ) species, but three-(AuL 3 ), and four-coordinate (AuL 4 ) species also exist. 7 These species differ in the presence of Au-based luminescence. 6 While Au-based luminescence is usually absent in AuL 4 complexes, it exists in AuL 2 complexes only in the presence of Au‚‚‚Au interactions.…”

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confidence: 99%

Jahn−Teller Distortion in the Phosphorescent Excited State of Three-Coordinate Au(I) Phosphine Complexes

2003

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Luminescent transition metal complexes have been receiving increasing attention due to their role in a variety of optoelectronic applications. For example, molecular light-emitting devices (LEDs) have been increasingly reported 1 to exhibit superior efficiencies when phosphorescence is enhanced by the presence of a heavy metal because of spin-orbit coupling. 2 Other complexes have been suggested as selective chemical sensors for volatile organics, 3 oxygen, 4 and specific ions 5 because the phosphorescence is reversibly enhanced or quenched on interaction with these species. 6 An understanding of the nature of the luminescent excited state, in addition to its fundamental significance, is essential for designing new materials with improved properties for such applications.Monovalent gold complexes represent one of the most celebrated classes of luminescent complexes. Gold(I) complexes most commonly exist as two-coordinate (AuL 2 ) species, but three-(AuL 3 ), and four-coordinate (AuL 4 ) species also exist. 7 These species differ in the presence of Au-based luminescence. 6 While Au-based luminescence is usually absent in AuL 4 complexes, it exists in AuL 2 complexes only in the presence of Au‚‚‚Au interactions. Meanwhile, AuL 3 complexes exhibit Au-based luminescence both with and without Au‚‚‚Au interactions present. [8][9][10] Reports by Gray 8 and Fackler 9 on the photophysical properties of monomeric [AuL 3 ] + complexes illustrated visible luminescence with very large Stokes' shifts (typically 10 000 cm -1 ), which suggests a significant excitedstate distortion. These authors suggested that on the basis of extended Hückel calculations and experimental spectral observations, the Stokes' shift is a result of a M-L bond shortening due to excitation from an antibonding HOMO to a bonding LUMO. More accurate information is obtained by fully optimizing the geometry of the excited-state independently because the excited molecule (exciton) should be dealt with as a different entity that is distinct from the ground-state molecule. 11 The present work provides a dramatic illustration of this for [The calculations herein were of two types: QM (quantum mechanical) and QM/MM (hybrid quantum mechanical/molecular mechanical). A general description of the calculations is given below 12 while full details are available in the Supporting Information, including tests done with a variety of basis sets and different levels of theory to calibrate the computational accuracy. For QM calculations [Au(PH 3 ) 3 ] + was used as a model, and different methodologies, including ab initio and DFT, and basis sets with various complexities were employed. The geometries of all models were fully optimized in both the ground and excited electronic states, with the latter being the lowest triplet state because the experimental lifetime data suggested that the emitting state is phosphorescent. 8,9 For QM/ MM calculations, [AuL 3 ] + models were used with L ) PMe 3 , PPh 3 , PPhCy 2 , and TPA (tris(1,3,5-triaza-7-phosphaadamantane)).The DFT calcul...

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“…Three-gold(I) complexes bearing two neutral ligands and one halogen are known and have been structurally characterized. [36] Thea nalogous species 15 b could be located using the complete JohnPhos ligand and despite the increased steric demand imposed by the full ligand 15 b lies only 28.8 kcal mol À1 above the parent carbenoid 7a (Supporting Information, Figure S35). Carbene 15 can react with one molecule of carbenoid 12 to yield the Au I À Au III dimer 16 without an apparent barrier by af ormal oxidative addition.…”

Section: Methodsmentioning

confidence: 99%

Gold(I) Carbenoids: On‐Demand Access to Gold(I) Carbenes in Solution

et al. 2017

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Chloromethylgold(I) complexes of phosphine, phosphite,a nd N-heterocyclic carbene ligands are easily synthesized by reaction of trimethylsilyldiazomethane with the corresponding gold chloride precursors.Activation of these gold(I) carbenoids with av ariety of chloride scavengers promotes reactivity typical of metallocarbenes in solution, namely homocoupling to ethylene,o lefin cyclopropanation, and Buchner ring expansion of benzene.Carbene complexes of transition metals are reactive intermediates [1] frequently invoked in awide variety of C À Cbondforming processes that range from industrial scale olefin metathesis [2] to natural product synthesis. [3] Despite their central role in gold catalysis, [4] few non-heteroatom-stabilized gold(I) carbene complexes have been structurally characterized.[5] Ther educed steric shielding provided by commonly used ligands and the intrinsically high electrophilicity [6] exhibited by simple gold(I) carbenes preclude their isolation in condensed phase.Such species are however of high interest as demonstrated by gas-phase studies by Chen, [7] Schwarz, [8] and others. [9] Theisolation of this type of compounds,ortheir functional equivalents,i st herefore of great importance for the fundamental understanding of the reactivity of electrophilic gold carbenes.T ransition-metal complexes of the type [M(CHXR)],formally defined as carbenoids, [10] show similar reactivity to their carbene counterparts [11] and offer an attractive alternative to otherwise non-isolable species.T o date,h owever, very little is known about gold(I) carbenoids and their reactivity.[12] Herein we report the synthesis of easily accessible gold carbenoids bearing bulky ligands as gold carbene equivalents in solution.Previous synthesis of chloromethylgold(I) complexes used either toxic and potentially explosive diazomethane [12a] or low-temperature in situ formation of Mg(CH 2 Cl)Cl.[12d] We have developed amore convenient approach that utilizes the methanol promoted decomposition of trimethylsilyldiazomethane [13,14] at room temperature (Scheme 1). Tr eatment of phosphine,phosphite,and NHC gold chloride complexes with trimethylsilyldiazomethane in benzene solution in presence of methanol afforded gold carbenoids 1a-d within minutes. Complexes 1a-c could be easily purified by column chromatography and have been fully characterized. Remarkably, these gold(I) carbenoids can be stored indefinitely when protected from air,a nd only decompose slowly when left under ambient conditions. Measured AuÀCd istances (Table 1) are close to 2.088-(9) observed for the previously reported [(PPh 3 )AuCH 2 Cl] complex (2).[12d] On the other hand, CÀCl distances (1.828-1.830 )are markedly longer than found in 2 (1.68(1) ), and Scheme 1. Synthesis of chloromethylgold(I) complexes 1a-d and structures of complexesa )1a,b)1b,c)and 1c.[38] ORTEP plots with ellipsoids set at 50 %p robability;h ydrogen atoms and solvent molecules are omitted for clarity.

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Three- and Four-Coordinate Gold(I) Complexes

Cited by 238 publications

References 117 publications

Structural characterization of dinuclear gold(I) diphosphine complexes with anion-triggered luminescence

Structural characterization of dinuclear gold(I) diphosphine complexes with anion-triggered luminescence

Jahn−Teller Distortion in the Phosphorescent Excited State of Three-Coordinate Au(I) Phosphine Complexes

Gold(I) Carbenoids: On‐Demand Access to Gold(I) Carbenes in Solution

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