Luminescent phosphine gold(I) alkynyl complexes. Highlights from 2010 to 2018

An overview of the homometallic phosphine-Au(I)alkynyl complexes reported in the literature from 2010 to 2018 have been collected and reported in this review article. They have been classified for better understanding, between mononuclear and polynuclear compounds. Their luminescent properties have been discussed along the text and the specific absorption and emission data collected in Annex I. This type of compounds are being used for a wide range of applications in fields such as biomedicine, chemosensors or luminescent materials among others and their interest is increasing in the last years. Some particular examples have been also selected herein

Supramolecular Gold Metallogelators: The Key Role of Metallophilic Interactions

Gold metallogelators is an emerging area of research. The number of results published in the literature is still scarce. The majority of these gels is observed in organic solvents, and the potential applications are still to be explored. In this work, we present an overview about gold metallogelators divided in two different groups depending on the type of solvent used in the gelation process (organogelators and hydrogelators). A careful analysis of the data shows that aurophilic interactions are a common motif directly involved in gelation involving Au(I) complexes. There are also some Au(III) derivatives able to produce gels but in this case the organic ligands determine the aggregation process. A last section is included about the potential applications that have been reported until now with this new and amazing class of supramolecular assemblies

Highlights on gold TADF complexes

Thermally activated delayed fluorescence (TADF) and TADF-organic light-emitting diodes (OLEDs) systems are being given increasing attention in research nowadays. Much more work has been done for organic-based materials in this field, but the use of TADF organometallic systems has also emerged in recent years. In particular, TADF-based gold compounds have not been particularly well-explored, with a higher number of examples of Au(I)-molecules and fewer for the higher oxidation state Au(III) derivatives. Nevertheless, the novelty and observed results deserve attention. A careful analysis has been performed in this review by classifying the reported compounds into two different groups regarding the oxidation state of the metal, and within each group, the ancillary ligands. Specific examples to illustrate their potential applications are included in the different sections

Construcció programada de polígons i poliedres moleculars i cinc cèntims de les seves aplicacions

[cat] En aquest article s'explica com les reaccions d'autoassemblatge (self-assembly) permeten la construcció racional i programada de molts metal·lomacrocicles o espècies discretes amb geometries poligonals o polièdriques. En una segona part, s'expliquen breument algunes de les aplicacions d'aquestes noves supramolècules com són la seva capacitat per a actuar com a nanoreactors, catalitzadors, sensors o tamisos moleculars. [eng] This paper shows how self-assembly reactions allow the building up of a wide range of metallomacrocycles (polygonal and polyhedral species) in a rational and programmed way. The second part presents a brief survey of some of the applications of these new supramolecules such as cavity-directed synthesis, catalysis, sensing or molecular sieving

Luminescent tetranuclear gold(I) dibenzo[g,p]chrysene derivatives: effect of the environment on photophysical properties

A new 2,7,10,15-tetraethynyldibenzo[g,p]chrysene ligand (1) and two tetranuclear gold(I) derivatives containing PPh3 (3) and PMe3 (4) phosphines were synthesized and characterized by 1H and 31P NMR, IR spectroscopy, and high-resolution mass spectrometry. The compounds were studied in order to analyze the e ect of the introduction of gold(I) on the supramolecular aggregation and photophysical properties. Absorption and emission spectra displayed broad bands due to the establishment of interactions as an indication of intermolecular contacts and the formation of aggregates. A decrease of the recorded quantum yield (QY) of the gold(I) derivatives was observed compared to the uncomplexed ligand. The introduction of the complexes into poly methyl methacrylate (PMMA) and Zeonex 480R matrixes was analyzed, and an increase of the measured QY of 4 in Zeonex was observed. No phosphorescent emission was detected

Tripodal gold(I) polypyridyl complexes and their Cu+ and Zn2+ heterometallic derivatives. Effects on luminescence

Three gold(I) tripodal complexes containing the tris(2-pyridylmethyl)amine (TPA) ligand coordinated to Au-PR3 moieties (PR3 = 1,3,5-triaza-7-phosphatricyclo[3.3.1.13.7]decane, PTA (1), 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane, DAPTA (2) and triphenylphosphane (3)) were prepared together with a cage-like structure containing triphosphane 1,1,1-tris(diphenylphosphinomethyl)ethane (4). The luminescence of these complexes has been studied and they show a red shift upon the formation of heterometallic complexes by reaction with Zn(NO3)2, CuCl and [Cu(CH3CN)4]BF4. The different coordination motifs of the Zn2+ and Cu+ heterometallic species and the resulting changes in the recorded absorption, emission and NMR spectra were analysed and supported by TD-DFT calculations

Influence of the attachment of a gold(I) phosphine moiety at the upper rim of a calix[4]pyrrole on the binding of tetraalkylammonium chloride salts

We report the synthesis of an unprecedent mono-gold(I) phosphine complex based on a 'two wall' aryl-ethynyl extended calix[4]pyrrole. We describe and compare the binding properties of the parent 10α,20α-bis-aryl-ethynyl calix[4]pyrrole ligand and the prepared organometallic compound as receptors for tetraalkylammonium chloride salts in dichloromethane and acetone solutions. We describe the results of 1H NMR, UV-vis titrations and isothermal titration calorimetry (ITC) experiments in DCM and acetone solution, aiming at thermodynamically characterize the formed complexes. The obtained results indicate a noticeable decrease in the binding affinity of the chloride for the mono-gold(I) receptor 1 compared to the parent ligand 2. The increase in the negative value of the electrostatic surface potential at the center of the aromatic ring of the gold(I) meso-aryl-ethynyl substituent serves to explain the observed results and the presence in solution of the chloride complex of 1 as a mixture of two conformers

Study of the effect of the chromophore and nuclearity on the aggregation and potential biological activity of gold(I) alkynyl complexes

The synthesis and characterization of four organometallic gold(I) complexes containing different water soluble phosphanes (TPPTS, PTA and DAPTA) and chromophoric units (4-pyridylethynyl and propargyloxycoumarin) is here reported. The analysis of their absorption and emission spectra led us to attribute their luminescent behavior to the chromophoric organic ligands. Moreover, the presence of the gold(I) metal atom has been observed to be the responsible of an efficient intersystem crossing process responsible for the observed phosphorescence emission. Broad emission bands are observed in most cases due to the formation of organized aggregates in solution in agreement with microscopic characterization. Biological activity of the complexes showed very low effects against tumor cell growth but an inhibitory potency against thioredoxin reductase (TrxR). The missing/low cytotoxic effects could be related to a low bioavailability as determined by atomic absorption spectroscopy. Graphical abstract The synthesis, characterization, aggregation and emissive properties of four organometallic gold(I) complexes containing different water soluble phosphanes and chromophoric units is here reported. Biological activity of the complexes showed very low effects against tumor cell growth but an inhibitory potency against thioredoxin reductase (TrxR

Platinum(II) compounds containing cyclometalated tridentate ligands: Synthesis, luminescence studies, and a selective fluoro for methoxy substitution

Two series of potentially tridentate ligands of formula ArCH=N(CH2)2NMe2 and ArCH=N(CH2)3NMe2 (Ar = C6H5, 2-FC6H4, 4-FC6H4, 2,3,4-F3C6H2) were used to prepare [C,N,N′]-cyclometalated platinum compounds containing either a chloro or a methyl ancillary ligand. The synthesis of the compounds [PtCl{Me2N(CH2)xN=CHR}] (3a−h), via the corresponding compounds [PtCl2{Me2N(CH2)xN=CHAr}] (2), requires drastic conditions and proceeds more easily for ligands derived from N,N-dimethylpropylenediamine (x = 3). Along the process, an unexpected selective nucleophilic substitution of a fluoro for a methoxy substituent took place at the aryl ring for ligands 2,3,4-F3C6H2CH=N(CH2)xNMe2. The syntheses of compounds [PtMe{Me2N(CH2)xN=CHR}] (4a−h) using [Pt2Me4(μ-SMe2)2] as a precursor took place for all ligands under relatively mild conditions. All compounds were fully characterized, including molecular structure determination for [PtCl{Me2N(CH2)3N=CH(4-FC6H3)}] (3b) and [PtCl{Me2N-(CH2)3N=CH(2-OMe,3,4-F2C6H)}] (3g). The absorption and emission spectra were also studied for the [C,N,N′]-cyclometalated platinum(II) compounds, and all of the compounds were emissive in the solid state and in dichloromethane solution at room temperature (compounds 3) or at 77 K (compounds 4). The size of the [N,N′]-chelate ring and the number and position of the substituents in the aryl ring modulate the intensity and the energy of the emission

Polarized supramolecular aggregates based on luminescent perhalogenated gold derivatives

Reaction of [Au(C6F5)(tht)] (tht = tetrahydrothiophene) with 1,3,5-triaza-7-phosphaadamantane (PTA) and 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]-nonane (DAPTA) leads to the formation of [Au(C6F5)(phosph)] (phosph = PTA, 1; phosph = DAPTA, 2). The compounds are slightly soluble in water and aggregate at higher concentrations giving rise to the formation of needle- and rod-like structures (1) and well-organized spherical aggregates (2). Compounds 1 and 2 were reacted with AgPF6 giving rise to the formation in all cases of luminescent water soluble 1:1 Au·Ag heterometallic complexes, as evidenced by X-ray crystal structure determination. The use of different silver salts that differ on the counterion induces changes on the resulting luminescence and aggregation morphology