Cap a catàlisi asimètrica utilitzant caixes pseudopeptídiques tripodals

Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2019, Tutors: Tutors: Laura Rodríguez Raurell, Ciril Jimeno MolletThe main goal of this project is the synthesis of a supramolecular pseudopeptidic cage that is be able to recognize chloride ions (Figure 1). This recognition will later be proved for asymmetric catalysis on different substrates. Three L-amino acids (phenylalanine) provide it the chiral centres that should allow the cage to act as an asymmetric catalyst. The interest in this kind of catalysis lies in getting enantiomerically enriched compounds, which have high synthetic interest and high value, even though the reagents have affordable prizesIn order to get the desired cage (which will be called [1+1] because it is formed by one aromatic electrophile and one tripodal amine) it is needed to use the template effect with the chloride. Thanks to that, the third step of its synthesis (a SN2 reaction between a triple benzyl bromide and a free triamine) will be promoted in a fully intramolecular way, yielding the desired cage. Finally, the cage has been characterized by 1H-NMR, 1H-1H (COSY), 13C-1H (HSQC) and by ESI-MS, too. Thanks to these techniques it is possible to identify each proton and with whom it interacts. In the period available, different substrates were tested to try the asymmetric reactions catalysed with the supramolecular cage. Finally, two reactions were studied: a β-chlorohydrine cyclization to yield epoxides, and a β-chloroacid cyclization to yield β-lactone

Impact on the Population of the Triplet Excited State

Publisher Copyright: © 2022 American Chemical Society. All rights reserved.Two series of dinuclear gold(I) complexes that contain two Au-chromophore units (chromophore = dibenzofurane or dimethylfluorene) connected through a diphosphane bridge that differs in the flexibility and length (diphosphane = dppb for 1,4-bis(diphenylphosphino)butane, DPEphos for bis[(2-diphenylphosphino)phenyl]ether, xanthphos for 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene, and BiPheP for 2,2′-bis(diphenylphosphino)-1,1′-biphenyl) have been synthesized and structurally characterized. Their photophysical properties have been carefully investigated, paying attention to the role of the presence, or absence, of aurophilic contacts and their nature (intra- or intermolecular character). This analysis was permitted due to the X-ray crystallographic determination of all of the structures of the compounds discussed herein. The quantum yields of the triplet population, φT, have been calculated by nanosecond-laser flash photolysis measurements, and we could determine the main role of the character of the aurophilic contacts in the resulting φT, being especially favored in the presence of intermolecular contacts. Time-dependent density functional theory (TD-DFT) calculations support the absorption and emission assignments and the shorter distance between S1and the closest triplet excited state energy in the case of the compounds with a higher triplet-state population.publishersversionpublishe

Intra- vs Intermolecular Aurophilic Contacts in Dinuclear Gold(I) Compounds: Impact on the Population of the Triplet Excited State

Two series of dinuclear gold(I) complexes that contain two Au–chromophore units (chromophore = dibenzofurane or dimethylfluorene) connected through a diphosphane bridge that differs in the flexibility and length (diphosphane = dppb for 1,4-bis(diphenylphosphino)butane, DPEphos for bis[(2-diphenylphosphino)phenyl]ether, xanthphos for 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene, and BiPheP for 2,2′-bis(diphenylphosphino)-1,1′-biphenyl) have been synthesized and structurally characterized. Their photophysical properties have been carefully investigated, paying attention to the role of the presence, or absence, of aurophilic contacts and their nature (intra- or intermolecular character). This analysis was permitted due to the X-ray crystallographic determination of all of the structures of the compounds discussed herein. The quantum yields of the triplet population, ϕT, have been calculated by nanosecond-laser flash photolysis measurements, and we could determine the main role of the character of the aurophilic contacts in the resulting ϕT, being especially favored in the presence of intermolecular contacts. Time-dependent density functional theory (TD-DFT) calculations support the absorption and emission assignments and the shorter distance between S1 and the closest triplet excited state energy in the case of the compounds with a higher triplet-state population

Gold(I)-doped films: new routes for efficient room temperature phosphorescent materials

The synthesis of four novel gold(I)-phosphane complexes coordinated to 9-phenanthrene chromophore has been carried out through the reaction of 9-phenanthreneboronic acid and the corresponding AuClPR3 (PR3 = PPh3 for triphenylphosphane (1a); 1,4-bis(diphenylphosphanyl)butane or dppb (2b); bis(diphenylphosphanyl)acetylene or dppa (2c); (AuCl)2(diphos) (diphos = bis(diphenylphosphanyl)methane or dppm (3)) sources. The X-ray crystal structures of compounds 1a and 2b show the existence of MOF-like intermolecular assemblies that contain empty inner cavities in the absence of aurophilic contacts. In contrast, the formation of a tetranuclear complex with intramolecular aurophilic interactions was evidenced for 3. Photophysical characterization indicates dual emission in all gold(I) complexes when oxygen is removed from the sample, while only fluorescence emission is recorded for the uncoordinated ligand. The introduction of the compounds within PMMA and Zeonex was assayed, and luminescent films containing gold(I) complexes where phosphorescence is the sole pathway for emission are obtained, instead of the dual emission (with significant fluorescence contribution) recorded in solution

Philippine Aquatic Wildlife Rescue and Response Manual Series: Marine Turtles

This manual addresses the lack of information materials on how to deal with marine turtle encounters in the Philippine seas to ensure that the proper treatment and intervention is provided. The manual also responds to the Comprehensive Action Plan for Threatened, Charismatic, and Migratory Species of the Sulu-Sulawesi Marine Ecoregion (SSME), which has been identified as the first priority seascape the Coral Triangle Initiative (CTI). The Tri-National Committee of the SSME developed the Comprehensive Action Plans (CAP) that identified seven Key Result Areas (KRAs) to improve the status of marine turtles in the SSME, as follows: (a) Identify best practices in minimizing threats to marine turtle populations and their habitats; (b) Develop and implement nesting habitats and management programs to maximize hatchling production and survival; (c) Provide recommendations on specific features or criteria in marine protected area (MPA) design and MPA network design in relation to the protection and management of marine turtles in SSME waters; (d) Undertake initiatives to promote reduction of incidental capture and mortality of marine turtles; (e) Conduct turtle population habitat research and monitoring protocols; (f) Develop guidelines for MPA network design for marine turtles; and (g) Publish information to promote best practices and successes for marine turtle conservation. This manual is an important step to address gaps and issues on threatened marine wildlife in the Philippines to better protect and conserve marine biodiversity in the Coral Triangle.The publication of this book is made possible through the collaboration of the Department of Environment and Natural Resources-Biodiversity Management Bureau (DENR-BMB), Marine Wildlife Watch of the Philippines (MWWP), and the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) through its Adaptation to Climate Change in Coastal Areas Project (ACCCoast). This project is part of the Internationale Klimaschutzinitiative (IKI). The German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB) supports this initiative on the basis of a decision adopted by the German Bundestag (http://www.international-climate-initiative.com)

Triplet harvesting of gold(I) supramolecular complexes and their applications

[eng] This thesis has been done under the supervision of Prof. Laura Rodríguez (Inorganic Chemistry Section, Universitat de Barcelona) and Prof. João Carlos Lima (LAQV REQUIMTE, Universidade Nova de Lisboa). Over these four years, several gold(I) organometallic complexes with different structural characteristics have been synthesized. The compounds present different nuclearities (number of metal atoms) and different chromophores and ancillary ligands. The different parts of the molecules play a direct influence on their resulting luminescent properties. Since gold(I) displays a linear geometry, the chromophores have been coordinated in one of these positions, in the other one, different phosphanes, and diphosphanes as ancillary ligands. The main aim of this Doctoral Thesis is to study the luminescent properties and photophysics of these compounds in order to deeply understand how to efficiently promote the harvesting of triplet excited states, Tn, which are those responsible for the resulting phosphorescence emission, in order to obtain room temperature phosphorescence materials (RTP). Other applications have been explored, such as sensing water pollutants and singlet oxygen production. The interest in preparing compounds suitable for RTP materials relies on the fact that when producing excitons through electricity, 25% of them populate the Sn states, while 75% of them harvest the Tn instead. The forbidden character of the triplet excited state and its lower energy favours non-radiative decays. Hence, the use of an efficient way to obtain luminescent materials with high phosphorescence quantum yield is a challenge. On the other hand, the high sensitivity of luminescence is of great relevance to be used to prepare luminescent chemosensors. The use of phosphorescence sensors can help detect other types of contaminants that present intrinsic fluorescence emission that appears at shorter wavelengths. Finally, the production of singlet oxygen has been widely studied in the last years, with great potential in several research fields, such as photodynamic therapy (promoting the formation of ROS species that can attack carcinogenic cells) or catalytic reactions (using the singlet oxygen specie as a green catalyst). The advantage is that singlet oxygen is generated from oxygen, O2, which is very abundant in our atmosphere and can be produced through energy transfer from triplet excited states of molecular sensitizer, leading to the quenching of these states. This energy transfer can take place because the ground state of the O2 is a triplet, which permits the simultaneous transition of both triplets (molecular sensitizer and dioxygen) to the singlet state (excited singlet state of dioxygen and ground singlet state of the molecular sensitizer). Compounds with heavy atoms in their chemical structure, that can have populated the triplet excited state, are good molecular sensitizers, favouring the production of singlet oxygen instead of giving rise to phosphorescence emission. This PhD thesis is divided in different chapters that contain different families of gold(I) complexes displaying diverse structures. The presence of the gold(I) metal unit is crucial for promoting what is called “heavy atom effect”, which induces the promotion of the population of Tn states. The phosphanes and diphosphanes used have been crucial to modulate their solubilities and, also, the intra- and intermolecular supramolecular interactions present in the complexes. These interactions can modify the luminescent properties that the compounds present. Not only π···π and C-H···π interactions can be promoted, but also the so-called aurophilic contacts. Different characterization techniques have been used to evidence the pure formation of the organic and organometallic molecules (1H and 31P NMR, IR, ESI, MALDI-TOF, and DRX). Their luminescent properties have been analysed through Uv-Vis absorption and emission spectra under different conditions such as air-equilibrated, N2-saturated, solid, low temperature, and immobilized into organic polymeric matrices. Their luminescence lifetimes and quantum yields have been also measured. All these characterization techniques have been done in our groups’ facilities at the University of Barcelona. Several photophysical characterization require the use of the laser flash photolysis equipment, and these measurements have been done at the Universidade Nova de Lisboa facilities at the LAQV@REQUIMTE (CHARM group), during a short stage period. These measurements have been crucial for this work since it helped us to calculate the quantum yields of the formation of the triplet excited states (φT). All in all, we have tried to give a bit of light on the analysis of the photophysical parameters of gold(I) complexes, mainly regarding the effects that can affect the triplet harvesting and resulting derived properties (room temperature phosphorescence vs singlet oxygen production).[cat] Aquesta tesi doctoral ha estat supervisada pels Prof. Laura Rodríguez (Secció Química Inorgànica – Universitat de Barcelona) i el Prof. João Carlos Lima (LAQV-REQUIMTE – Universidade Nova de Lisboa). El treball realitzat explora la síntesi i caracterització estructural i fotofísica de complexos organometàl·lics d’or(I) amb propietats luminescents. La recerca es centra en entendre com es poden aprofitar eficientment els estats excitats triplets (Tn) per tal de facilitar la possible emissió fosforescent a temperatura ambient, així com altres aplicacions com poden ser la detecció de contaminants i la producció d’oxigen singlet. La importància dels estats Tn rau en el seu paper en l’eficiència quàntica dels materials fosforescents. Mentre que el 25% dels excitons poblen els estats singlets (Sn), un substancial 75% ocupen els estats Tn. Utilitzar eficientment els fotons dels estats Tn podria arribar a millorar clarament el seu rendiment quàntic de fosforescència . Els sensors fosforescents, per altre banda, en contraposició als fluorescents, permeten la detecció d’analits fluorescents, ja que no presenten problemes de superposició de bandes i, a més a més, permeten treballar amb límits de detecció més baixos i metodologies més simples per l’usuari, en comparació amb altres tècniques analítiques. La tesi també s’endinsa en la producció d’oxigen singlet, una espècie molt reactiva beneficiosa per a aplicacions com la teràpia fotodinàmica i la catàlisi verda, entre altres. La formació d’aquesta espècie és d’elevat interès degut al fet que prové de l’excitació de la molècula d’oxigen, O2, que té una abundància significativa a l’ atmosfera. A més, cal afegir que aquesta molècula presenta excepcionalment un estat fonamental de tipus triplet, fet que permet que la transició amb els Tn d’altres molècules presents al medi no estigui prohibida per espín. El treball realitzat presenta diversos complexos d’or(I), posant èmfasi en l’efecte de l’àtom pesat de l’or(I) en la promoció de la formació d’estats Tn. L’elecció de determinades fosfines i difosfines, com a lligands auxiliars, permet modular la solubilitat i les interaccions supramoleculars, amb una influència clara a les propietats luminescents resultants. Aquestes interaccions inclouen π···π, C-H···π, i contactes aurofílics, Au···Au. La utilització de diverses tècniques de caracterització com RMN multinuclear, IR, ESI, MALDI-TOF, i DRX han confirmat la correcta formació i puresa de les molècules sintetitzades. Les propietats luminescents van ser analitzades a través d’espectres d’absorció i emissió uv-vis sota diverses condicions (solució, estat sòlid, matrius orgàniques i a diferents temperatures), amb temps de vida mitjana d’emissió i rendiments quàntics d’emissió mesurats. La majoria de caracteritzacions es van realitzar a la Universitat de Barcelona, exceptuant els estudis amb “laser flash photolysis” que es varen dur a terme a la Universidade Nova de Lisboa. Aquests estudis van ser clau en la determinació dels rendiments quàntics de la formació d’estats Tn (φT). Aquest estudi exhaustiu contribueix a la comprensió dels complexos luminescents d’or(I), oferint perspectives sobre les seves aplicacions potencials i els mecanismes relatius al seu comportament luminescent

Intra- vs Intermolecular Aurophilic Contacts in Dinuclear Gold(I) Compounds : Impact on the Population of the Triplet Excited State

Two series of dinuclear gold(I) complexes that contain two Au–chromophore units (chromophore = dibenzofurane or dimethylfluorene) connected through a diphosphane bridge that differs in the flexibility and length (diphosphane = dppb for 1,4-bis(diphenylphosphino)butane, DPEphos for bis[(2-diphenylphosphino)phenyl]ether, xanthphos for 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene, and BiPheP for 2,2′-bis(diphenylphosphino)-1,1′-biphenyl) have been synthesized and structurally characterized. Their photophysical properties have been carefully investigated, paying attention to the role of the presence, or absence, of aurophilic contacts and their nature (intra- or intermolecular character). This analysis was permitted due to the X-ray crystallographic determination of all of the structures of the compounds discussed herein. The quantum yields of the triplet population, ϕT, have been calculated by nanosecond-laser flash photolysis measurements, and we could determine the main role of the character of the aurophilic contacts in the resulting ϕT, being especially favored in the presence of intermolecular contacts. Time-dependent density functional theory (TD-DFT) calculations support the absorption and emission assignments and the shorter distance between S1 and the closest triplet excited state energy in the case of the compounds with a higher triplet-state population.peerReviewe

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

The synthesis of two series of gold(I) complexes containing the general formulae PR 3 ‐Au‐C≡C‐phenanthrene (PR 3 = PPh 3 ( 1a / 2a ), PMe 3 ( 1b / 2b ), PNaph 3 ( 1c / 2c )) or (diphos)(Au‐C≡C‐phenanthrene) 2 (diphos = 1,1‐ bis (diphenylphosphino)methane, dppm ( 1d / 2d ); 1,4‐ bis (diphenylphosphino)butane, dppb ( 1e / 2e )) have been synthesized. The two series differ on 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 1 H and 31 P NMR and IR spectroscopy, mass spectrometry and single crystal X‐ray diffraction resolution in the case of compounds 1a , 1e , 2a , and 2c . The emissive properties of the uncoordinated ligands and corresponding complexes have been studied in solution and within organic matrixes of different polarity (PMMA and Zeonex). We have observed room temperature phosphorescence (RTP) for all gold(I) complexes while only fluorescence can be detected for the pure organic chromophore. In particular, the L2 ‐series present better luminescent properties regarding intensity of emission, quantum yields and RTP effect. Additionally, while the inclusion of all the compounds in organic matrixes induces an enhancement of the observed RTP due to the decrease in non‐radiative deactivation, only the L2 ‐series completely supress fluorescence giving rise to pure phosphorescent materials.peerReviewe