Recent progress on supramolecular luminescent assemblies based on aurophilic interactions in solution

The development of supramolecular systems showing aurophilic interactions in solution is gaining much attention in the last years. This is due to the intriguing photophysical properties of gold(I) complexes, which usually confer to these supramolecular assemblies interesting luminescent properties, as well as the possibility of morphological modulation, through fine tuning of inter-and intramolecular aurophilic interactions, in synergy with the formation of other supramolecular contacts. In this work, an overview of the advances made in this area since 2015 is presented. A large variety of systems showing different spectroscopical and structural topologies has been reported. Moreover, these supramolecular assemblies have proven to be useful in a wide range of application

Base-assisted synthesis of 4-pyridinate gold(I) metallaligands: a study of their use in self-assembly reactions

The synthesis of di- and tritopic gold(I) metallaligands of the type [(Au4-py)2(μ2-diphosphane)] (diphosphane = bis(diphenylphosphanyl)isopropane or dppip (1), 1,2-bis(diphenylphosphanyl)ethane or dppe (2), 1,3-bis(diphenylphosphanyl)propane or dppp (3) and 1,4-bis(diphenylphosphanyl)butane or dppb (4)) and [(Au4-py)3(μ3-triphosphane)] (triphosphane = 1,1,1-tris(diphenylphosphanylmethyl)ethane or triphos (5) and 1,3,5-tris(diphenylphosphanyl)benzene or triphosph (6)) from [(AuCl)2(μ2-diphosphane)] or [(AuCl)3(μ3-triphosphane)] and 4-pyridylboronic acid in the presence of Cs2CO3 has been conducted. Interestingly, when [(AuCl)2(μ2-dppm)] (dppm = bis(diphenylphosphanyl)methane) was used as a starting material, the cyclic tetranuclear gold(I) compound [(Au4-py)2(CH)2{μ2-Au(PPh2)2}2] (I) was obtained instead. All the products have been characterized by IR and multinuclear NMR spectroscopy, mass spectrometry and elemental analysis and in the case of 1, 3, 5 and I by X-ray crystallography, which showed the presence of aurophilic interactions in all of them. The obtained metallaligands have been used as building blocks in self-assembly reactions with cis-blocked palladium or platinum acceptor moieties producing [2 + 2] metallamacrocycles or trigonal bipyramidal (TBP) [2 + 3] metallacages in good yields. The photophysical properties of both the metallaligands and the corresponding assemblies have been investigated

Exploring the heavy atom effect and supramolecular assemblies of Au(I) and Pt(II) complexes

Programa de Doctorat en Química Orgànica / Tesi realitzada a l'Institut de Nanociència i Nanotecnologia[eng] This thesis is mainly focused on studying the photophysical properties of Au(I), Ag(I), Cu(I), and Pt(II) coordinated compounds. This work can be divided into two parts: on the one hand, the compounds of the group 11 metals and, on the other hand, the Pt(II) compounds. In the case of the group 11 metals, Au(I) compounds with different chromophore groups have been synthesized. These compounds contain the pyridyl diphenylphosphane ligand in their structure. These compounds were designed to be used as supports. They allow the introduction of a second metal, which promotes the formation of metallophilic interactions. For the Pt(II) compounds, the synthesis of [N^N^N] ligands with different structural modifications has been carried out in order to modulate the electronic properties in the resulting coordination compounds. Various neutral ligands, such as pyridines and diphosphines, were used to study the effect of coordination at the fourth available position in the Pt(II) atoms. These ligands have been rationally chosen in order to rationalize the effects of these structures on the photophysical properties of the compounds, with the aim of modifying and/or generating supramolecular structures supported by non-covalent interactions. The design of the different compounds was aimed at promoting the generation of singlet oxygen in solution by forming structures containing a large number of metal atoms. The research group worked on the development of a new methodology for the detection of this specie in solution. The method used was a direct measurement method. This method was applied to most of the compounds synthesized in this work. It helped to lay the foundation for the design of molecules with higher activities as chemical photosensitizers.[spa] Esta tesis doctoral está enfocada principalmente al estudio de las propiedades fotofísicas de compuestos de coordinación de Au(I), Ag(I), Cu(I) y Pt(II). Este trabajo se puede dividir en dos partes: por un lado, los compuestos de metales del grupo 11 y, por otro, los compuestos de Pt(II). En el caso de los metales del grupo 11 se sintetizaron compuestos de Au(I) con diversos grupos cromóforos, los cuales contenían en su estructura el ligando piridildifenilfosfina. El diseño de estos compuestos fue realizado para emplearlos como soportes que permitieran la introducción de un segundo metal promoviendo la formación de interacciones metalofílicas. Para los compuestos de Pt(II) se realizó la síntesis de ligandos [N^N^N] con diversas modificaciones estructurales para modular las propiedades electrónicas en los compuestos de coordinación resultantes. Fue estudiado de manera exhaustiva el efecto de la coordinación en la cuarta posición disponible en los átomos de Pt(II) con diferentes ligandos neutros como lo son piridinas y difosfinas. Estos ligandos fueron elegidos de manera racional buscando la modificación y/o generación de estructuras supramoleculares soportadas por interacciones no covalentes con el objetivo de racionalizar los efectos de estas estructuras sobre las propiedades fotofísicas de los compuestos. El diseño de los diferentes compuestos fue pensado para promover, por medio de la formación de estructuras con un gran número de átomos metálicos, la generación de oxígeno singulete en solución. En el grupo de investigación se trabajó en el desarrollo una nueva metodología para la detección de esta especie en solución con un método de medición directo. Dicho método fue aplicado en gran parte de los compuestos sintetizados en este trabajo y ayudó a asentar bases para el diseño de moléculas con mayores actividades como fotosensibilizadores químicos

Exploring the heavy atom effect and supramolecular assemblies of Au(I) and Pt(II) complexes

[eng] This thesis is mainly focused on studying the photophysical properties of Au(I), Ag(I), Cu(I), and Pt(II) coordinated compounds. This work can be divided into two parts: on the one hand, the compounds of the group 11 metals and, on the other hand, the Pt(II) compounds. In the case of the group 11 metals, Au(I) compounds with different chromophore groups have been synthesized. These compounds contain the pyridyl diphenylphosphane ligand in their structure. These compounds were designed to be used as supports. They allow the introduction of a second metal, which promotes the formation of metallophilic interactions. For the Pt(II) compounds, the synthesis of [N^N^N] ligands with different structural modifications has been carried out in order to modulate the electronic properties in the resulting coordination compounds. Various neutral ligands, such as pyridines and diphosphines, were used to study the effect of coordination at the fourth available position in the Pt(II) atoms. These ligands have been rationally chosen in order to rationalize the effects of these structures on the photophysical properties of the compounds, with the aim of modifying and/or generating supramolecular structures supported by non-covalent interactions. The design of the different compounds was aimed at promoting the generation of singlet oxygen in solution by forming structures containing a large number of metal atoms. The research group worked on the development of a new methodology for the detection of this specie in solution. The method used was a direct measurement method. This method was applied to most of the compounds synthesized in this work. It helped to lay the foundation for the design of molecules with higher activities as chemical photosensitizers.[spa] Esta tesis doctoral está enfocada principalmente al estudio de las propiedades fotofísicas de compuestos de coordinación de Au(I), Ag(I), Cu(I) y Pt(II). Este trabajo se puede dividir en dos partes: por un lado, los compuestos de metales del grupo 11 y, por otro, los compuestos de Pt(II). En el caso de los metales del grupo 11 se sintetizaron compuestos de Au(I) con diversos grupos cromóforos, los cuales contenían en su estructura el ligando piridildifenilfosfina. El diseño de estos compuestos fue realizado para emplearlos como soportes que permitieran la introducción de un segundo metal promoviendo la formación de interacciones metalofílicas. Para los compuestos de Pt(II) se realizó la síntesis de ligandos [N^N^N] con diversas modificaciones estructurales para modular las propiedades electrónicas en los compuestos de coordinación resultantes. Fue estudiado de manera exhaustiva el efecto de la coordinación en la cuarta posición disponible en los átomos de Pt(II) con diferentes ligandos neutros como lo son piridinas y difosfinas. Estos ligandos fueron elegidos de manera racional buscando la modificación y/o generación de estructuras supramoleculares soportadas por interacciones no covalentes con el objetivo de racionalizar los efectos de estas estructuras sobre las propiedades fotofísicas de los compuestos. El diseño de los diferentes compuestos fue pensado para promover, por medio de la formación de estructuras con un gran número de átomos metálicos, la generación de oxígeno singulete en solución. En el grupo de investigación se trabajó en el desarrollo una nueva metodología para la detección de esta especie en solución con un método de medición directo. Dicho método fue aplicado en gran parte de los compuestos sintetizados en este trabajo y ayudó a asentar bases para el diseño de moléculas con mayores actividades como fotosensibilizadores químicos

Heterometallic Au(I)–Cu(I) Clusters : Luminescence Studies and 1O2 Production

Two different organometallic gold(I) compounds containing naphthalene and phenanthrene as fluorophores and 2-pyridyldiphenylphosphane as the ancillary ligand were synthesized (compounds 1 with naphthalene and 2 with phenanthrene). They were reacted with three different copper(I) salts with different counterions (PF6–, OTf–, and BF4–; OTf = triflate) to obtain six Au(I)/Cu(I) heterometallic clusters (compounds 1a–c for naphthalene derivatives and 2a–c for phenanthrene derivatives). The heterometallic compounds present red pure room-temperature phosphorescence in both solution, the solid state, and air-equilibrated samples, as a difference with the dual emission recorded for the gold(I) precursors 1 and 2. The presence of Au(I)–Cu(I) metallophilic contacts has been identified using single-crystal X-ray diffraction structure resolution of two of the compounds, which play a direct role in the resulting red-shifted emission with respect to the gold(I) homometallic precursors. Polystyrene (PS) and poly(methyl methacrylate) (PMMA) polymeric matrices were doped with our luminescent compounds, and the resulting changes in their emissive properties were analyzed and compared with those previously recorded in the solution and the solid state. All complexes were tested to analyze their ability to produce 1O2 and present very good values of ΦΔ up to 50%.peerReviewe

Investigating the Impact of Packing and Environmental Factors on the Luminescence of Pt(N^N^N) Chromophores

Four Pt(II)(N^N^N) compounds featuring DMSO coordination at the fourth position were synthesized. Ligands varied in terms of pyridyl central ring (hydrogen/chlorine substituent) and lateral rings (triazoles with CF3 substitution or tetrazoles). Coordination to pyridine yielded tetra-nitrogen coordinated Pt(II) complexes or Pt-functionalized polymers using commercial 4-pyridyl polyvinyl (PV) or dimethylaminopyridine. Luminescence behaviors exhibited remarkable environmental dependence. While some of the molecular compounds (tetrazole derivatives) in solid state displayed quenched luminescence, all the polymers exhibited 3MMLCT emission around 600 nm. Conversely, monomer emission was evident on poly(methyl methacrylate) or polystyrene matrices. DFT calculations were used to analyze the aggregation of the complexes both at the molecular level and coordinated to the PV polymer and their influence on the HOMO–LUMO gaps

Gold(I) complexes bearing a PNP-type pincer ligand: photophysical properties and catalytic investigations

The synthesis and characterization of two dinuclear and five tetranuclear gold(I) complexes bearing the 2,6-bis(diphenylphosphinomethyl)pyridine diphosphane ligand (DPPMPY) are herein reported. The reaction between the dinuclear complexes, DPPMPY(AuCl)2 (1) or DPPMPY(AuBr)2 (2), with 1 or 2 equivalents of Ag salts yielded five tetranuclear gold(I) complexes, DPPMPY2Au4X2 (3-7), differing in the terminal ancillary ligands (X = Cl, Br, acetonitrile) and the counter ions (SbF6− or BF4−). The structures of complexes 1, 2, 3, and 5 were confirmed by single-crystal X-ray diffraction studies. The Au⋯Au distances found in complexes 3 and 5 are in the range of aurophilic interactions and the arrangement of the Au atoms varies from a linear arrangement in complex 3 to a zigzag arrangement in complex 5. The photophysical characterization of the compounds was performed both in solution and in the solid state. Very high emission quantum yields were observed for the acetonitrile complexes 4 and 6 in the solid state. The use of this family of gold(I) complexes as catalysts for lactone synthesis via oxidative heteroarylation of alkenes was investigated and yields up to ca. 65% were obtained. Dicationic halide complexes 3 and 5 showed a slight enhancement of the yield of the catalytic reaction, indicating that there is no influence of the counter ion employed on the reaction outcome. Luminescence techniques have been also used to follow the progress of the catalytic reaction

Supercritical CO₂ Synthesis of Porous Metalloporphyrin Frameworks: Application in Photodynamic Therapy

A series of porous metalloporphyrin frameworks prepared from the 5,10,15,20-tetra(4-pyridyl)porphyrin (H2TPyP) linker and four metal complexes, M(hfac)2 M = Cu(II), Zn(II), Co(II), and Ni(II) (hfac: 1,1,1,5,5,5-hexafluoroacetylacetonate), were obtained using supercritical CO2 (scCO2) as a solvent. All the materials, named generically as [M-TPyP]n, formed porous metal–organic frameworks (MOFs), with surface areas of ∼450 m2 g–1. All MOFs were formed through the coordination of the metal to the exocyclic pyridine moieties in the porphyrin linker. For Cu(II), Zn(II), and Co(II), incomplete metal coordination of the inner pyrrole ring throughout the structure was observed, giving place to MOFs with substitutional defects and leading to a certain level of disorder and limited crystallinity. These samples, prepared using scCO2, were precipitated as nano- to micrometric powders. Separately, a layering technique from a mixture of organic solvents was used to crystallize high-quality crystals of the Co(II) based MOF, obtained with the formula [{Co(hfac)2}2H2TPyP]n. The crystal structure of this MOF was elucidated by single-crystal synchrotron X-ray diffraction. The Zn(II)-based MOF was selected as a potential photodynamic therapy drug in the SKBR-3 tumoral cell line showing outstanding performance. This MOF resulted to be nontoxic, but after 15 min of irradiation at 630 nm, using either 1 or 5 μM concentration of the product, almost 70% of tumor cells died after 72 h