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The elucidation of metal-dependent biological processes requires selective reagents for manipulating metal ion levels within biological solutions such as growth media or cell lysates. To this end, we immobilized a phosphine sulfide-stabilized phosphine (PSP) ligand on agarose to create a resin for the selective removal of copper from chemically complex biological media through simple filtration or centrifugation. Comprised of a conformationally preorganized phenylene-bridged backbone, the PSP-ligand binds Cu(I) with a 1:1 stoichiometry and exhibits a pH-independent Cu(I) dissociation constant in the low zeptomolar range. Neither Zn(II), Fe(II), nor Mn(II) interact with the ligand at millimolar concentrations, thus offering a much-improved selectivity towards copper over other commonly employed solid-supported chelators such as Chelex 100. As revealed by X-ray fluorescence elemental analysis, the immobilized chelator effectively removes copper from cell culture growth media and cell lysate isolated from mouse fibroblasts. In addition to preparing copper-depleted media or cell lysates for biological studies, PSP-immobilized ligands might prove equally useful for applications in radiochemistry, materials science, and environmental science.

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Palladium-catalyzed coupling reactions of small nucleophiles are of great interest, but challenging due to difficulties in selectivity control. Herein, we report the development of a new platform of P,N-ligands consisting of ylide-functionalized phosphines with aminophosphonium groups (NYPhos) to address this challenge. These phosphine ligands are easily accessible in a wide structural diversity with highly modular electronic and steric properties. Based on a family of 14 ligands the selective monoarylation of acetone as well as other challenging ketones and amides was accomplished with record-setting activities even for aryl chlorides at room temperature including late-stage functionalizations of drug molecules. Moreover, ammonia and other small primary amines could be coupled at mild conditions. Isolation and structure analyses of palladium complexes within the catalytic cycle confirmed that the P,N-coordination mode is necessary to achieve the observed selectivities. It also demonstrated the facile adjustability of the N-donor strength, which is beneficial for the targeted design of tailored P,N-ligands for future applications.

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Ruthenium complexes containing triphenylphosphine diamide ligands were prepared, characterized, and tested for their biological activity against various cancer cell lines and the malaria parasite, Plasmodium falciparum. The effect of M (mono-substituted) and B (bis-substituted) complexes on the human cervical carcinoma (HeLa) cell line was investigated using the MTT assay. Five (B2, B3, B5, B6, and B13) of the 24 synthesized ruthenium complexes showed significant effects with IC50 values ranging between 0.3 and 2.3 µM. Evaluation of the potential biomolecular targets of B2 and B13 by fluorescence spectroscopy revealed relevant interactions with BSA and only a weak affinity for ctDNA. Complexes M2, B2, M13 and B13 were selected for further biological characterization. Their effect on the viability of two ovarian cancer cell lines was compared to normal cell lines, denoting their selectivity. Upon treatment of four different drug-resistant gynaecological cancer cell lines, differing in their multidrug-resistant phenotypes, the efficacy of the bis-substituted complexes was shown to be greater than their mono-substituted counterparts. The non-MDR cells are sensitive to all the tested complexes, compared to MDR cells which are less sensitive. Upon investigation of complexes M2, M13, B2, and B13 against sensitive and multidrug-resistant parasite strains of P. falciparum, the bis-substituted complexes were again shown to be the most potent, with submicromolar activity against both strains. Furthermore, the resistance indexes for the complexes were approximately equal to 1, which is at least 5-fold lower than chloroquine diphosphate, suggesting the ability of these complexes to retain their activity in resistant forms of the parasite.

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A new class of palladium-indenyl complexes characterized by the presence of one bulky alkyl isocyanide and one aryl phosphine serving as ancillary ligands has been prepared, presenting high yields and selectivity. All the new products were completely characterized using spectroscopic and spectrometric techniques (NMR, FT-IR, and HRMS), and, for most of them, it was also possible to define their solid-state structures via X-ray diffractometry, revealing that the indenyl fragment always binds to the metal centre with a hapticity intermediate between ƞ3 and ƞ5. A reactivity study carried out using piperidine as a nucleophilic agent proved that the indenyl moiety is the eligible site of attack rather than the isocyanide ligand or the metal centre. All complexes were tested as potential anticancer agents against three ovarian cancer cell lines (A2780, A2780cis, and OVCAR-5) and one breast cancer cell line (MDA-MB-231), displaying comparable activity with respect to cisplatin, which was used as a positive control. Moreover, the similar cytotoxicity observed towards A2780 and A2780cis cells (cisplatin-sensitive and cisplatin-resistant, respectively) suggests that our palladium derivatives presumably act with a mechanism of action different than that of the clinically approved platinum drugs. For comparison, we also synthesized Pd-ƞ3-allyl derivatives, which generally showed a slightly higher activity towards ovarian cancer cells and lower activity towards breast cancer cells with respect to their Pd-indenyl congeners.

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Phosphine-functionalized metal-organic frameworks (P-MOFs) as an emerging class of coordination polymers, have provided novel opportunities for the development of heterogeneous catalysts. Yet, compared with the ubiquitous phosphine systems in homogeneous catalysis, heterogenization of phosphines in MOFs is still at its early stage. In this Minireview, we summarize the synthetic strategies, characterization and catalytic reactions based on the P-MOFs reported in literature. In particular, various catalytic reactions are discussed in detail in terms of phosphine ligand structure-function relationship, including the potential obstacles for future development. Finally, we discuss the possible solutions, including new types of reactions and techniques as the perspectives for the development of P-MOF catalysts, highlighting the opportunities and challenges.

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Ligands containing ferrocene backbones often feature both planar chirality and asymmetric centers, making them attractive options for asymmetric catalysis. Ugi's amine is a ubiquitous ferrocene-based chiral building block that can be functionalized to form a variety of tunable Josiphos ligands; however, few sources lay out the route from start to finish. Starting from ferrocene, we compile a synthetic route to an air- and moisture-stable copper(I)-Josiphos complex via enantiopure Ugi's amine, providing a potential one-stop shop for the synthesis of a wide range of Josiphos ligands.

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Machine learning has revolutionized information processing for large datasets across various fields. However, its limited interpretability poses a significant challenge when applied to chemistry. In this study, we developed a set of simple molecular representations to capture the structural information of ligands in palladium-catalyzed Sonogashira coupling reactions of aryl bromides. Drawing inspiration from human understanding of catalytic cycles, we used a graph neural network to extract structural details of the phosphine ligand, a major contributor to the overall activation energy. We combined these simple molecular representations with an electronic descriptor of aryl bromide as inputs for a fully connected neural network unit. The results allowed us to predict rate constants and gain mechanistic insights into the rate-limiting oxidative addition process using a relatively small dataset. This study highlights the importance of incorporating domain knowledge in machine learning and presents an alternative approach to data analysis.

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The systematic induction of structural defects at the atomic level is crucial to metal nanocluster research because it endows cluster-based catalysts with highly reactive centers and allows for a comprehensive investigation of viable reaction pathways. Herein, by substituting neutral phosphine ligands for surface anionic thiolate ligands, we establish that one or two Au3 triangular units can be successfully introduced into the double-stranded helical kernel of Au44 (TBBT)28 , where TBBT=4-tert-butylbenzenethiolate, resulting in the formation of two atomically precise defective Au44 nanoclusters. Along with the regular face-centered-cubic (fcc) nanocluster, the first series of mixed-ligand cluster homologues is identified, with a unified formula of Au44 (PPh3 )n (TBBT)28-2n (n=0-2). The Au44 (PPh3 )(TBBT)26 nanocluster having major structural defects at the bottom of the fcc lattice demonstrates superior electrocatalytic performance in the CO2 reduction to CO. Density functional theory calculations indicate that the active site near the defects significantly lowers the free energy for the *COOH formation, the rate-determining step in the whole catalytic process.

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Low-valent metal-organic frameworks (LVMOFs) and related materials have gained interest due to their potential applications in heterogeneous catalysis. However, of the few LVMOFs that have been reported, none have shown catalytic activity. Herein, a low-valent metal-organic material constructed from phosphine linkers and IrI nodes is reported. This material is effectively a crystalline, insoluble analogue of Vaska's complex. As such, the material reversibly binds O2 and catalyzes the reductive formation of enamines from amides.

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Half-sandwich MII(cym)Cl (cym = Î·6-p-cymene; M = Ru, Os) complexes of pyridinecarbothioamide (PCA) ligands have demonstrated potential as orally active anticancer agents. In order to investigate the impact of the substitution of the labile chlorido ligand with phosphorous donor ligands on the antiproliferative properties, the triphenylphosphine (PPh3) and 1,3,5-triaza-7-phophaadamantane (pta) analogues were prepared and characterized by spectroscopic techniques and the molecular structures of several complexes were determined by X-diffraction analysis. Interestingly, the molecular structures contained the PCA ligand deprotonated, presumably driven by the reduction in overall charge of the complex. Density Functional Theory (DFT) calculations suggested minor energy differences between the protonated and deprotonated forms. The aqueous stability and the reactivity with the amino acids l-histidine and l-cysteine were investigated by 1H NMR spectroscopy of representative examples. The most potent anticancer agents featured Ru or Os centers and a PPh3 ligand and showed IC50 values in the submicromolar range against four cancer cell lines. This suggests that the antiproliferative activity was mainly dependent on the lipophilic properties of the phosphine ligand with PPh3 having a significantly higher clog P value than pta.

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Cu(I) 4H-imidazolate complexes are rare examples of Cu(I) complexes with chelating anionic ligands and are potent photosensitizers with unique absorption and photoredox properties. In this contribution, five novel heteroleptic Cu(I) complexes with monodentate triphenylphosphine co-ligands are investigated. As a consequence of the anionic 4H-imidazolate ligand and in contrast to comparable complexes with neutral ligands, these complexes are more stable than their homoleptic bis(4H-imidazolato)Cu(I) congeners. Here, the ligand exchange reactivity was studied by 31 P-,19 F-, and variable temperature NMR and the ground state structural and electronic properties by X-ray diffraction, absorption spectroscopy, and cyclic voltammetry. The excited-state dynamics were investigated by femto- and nanosecond transient absorption spectroscopy. The observed differences, with respect to chelating bisphosphine bearing congeners, are often due to the increased geometric flexibility of the triphenylphosphines. These observations render the investigated complexes interesting candidates for photo(redox)reactions not accessible with chelating bisphosphine ligands.

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We report here a series of original ligand-supported trigonal planar Au@Ag3 clusters exhibiting bright solid-state phosphorescence in violet to deep-blue range (λmax =410-442 nm) with remarkably short decay times (0.36-1.36 µs) and up to 96 % emission quantum yield at 298 K.

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The synthesis, characterisation, and evaluation of the in vitro cytotoxicity of five maleonitriledithiolate-based ruthenium metal complexes bearing various phosphine ligands towards two ovarian cancer cell lines (A2780 and A2780cisR), one non-small-cell lung cancer cell line (H460) and one normal prostate cell line (PNT2) are presented herein. These 18-electron complexes were designed with four water-soluble phosphine ligands to increase the water-solubility character of the corresponding electron-deficient ruthenium complex which showed great in vitro promises, and triphenylphosphine for comparison. The complexes with triphenylphosphine-3,3',3''-trisulfonic acid and triphenylphosphine present similar cytotoxicity compared to the 16-electron precursor, with equal cytotoxicity to both A2780 and A2780cisR. Hints at the mechanism of action suggest an apoptotic pathway based on reactive oxygen species (ROS) production. No toxicity was observed in preliminary in vivo pilot studies for these two complexes in subcutaneous A2780 and A2780cisR xenograft models, with some evidence of tumour growth delay.

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Although ylides are commonly used reagents in organic synthesis, the parent methylphosphine MePH2 only exists in its phosphine form in the condensed phase. Its ylide tautomer H3 P+ -CH2 - is considerably higher in energy. Here, we report on the formation of bis(sulfonyl)methyl-substituted phosphines of the type (RO2 S)2 C(H)-PR2, which form stable PH ylides under ambient conditions, amongst the first examples of an acyclic phosphine which only exists in its PH ylide form. Depending on the exact substitution pattern the phosphines form an equilibrium between the PH ylide and the phosphine form or exist as one of both extremes. These phosphines were found to be ideal starting systems for the facile formation of α-carbanionic phosphines. The carbanion-functionalization leads to a switch from electron-poor to highly electron-rich phosphines with strong donor abilities and high basicities. Thus, the phosphines readily react with different electrophiles exclusively at the phosphorus atom and not at the carbanionic center. Furthermore, the anionic nature of the phosphines allows the formation of zwitterionic complexes as demonstrated by the isolation of a gold(I) complex with a cationic metal center. The cationic gold center allows for catalytic activity in the hydroamination of alkyne without requiring a further activation step.

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Metal-organic frameworks (MOFs) are crystalline, 2- and 3-dimensional coordination polymers formed by bonding interactions between metals and multitopic organic ligands. These are typically formed using hard Lewis basic organic ligands with high oxidation state metal ions. The use of low-valent metals as structural elements in MOFs is far less common, despite the widespread use of such metals for catalysis, luminescence, and other applications. This Minireview focuses on recent advances in the field of low-valent MOFs and offers a perspective on the future development of these materials.

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The confinement of a catalytic site is an efficient strategy to control a reaction and modulate its selectivity. In the present work, a new class of structurally simple and easily accessible bulky tri-(ortho-biaryl)phosphine ligands were accessed, and their gold(I) complexes synthesized. Their X-ray diffraction analysis and the comparative evaluation of their VBur % and G steric parameters against a series of gold complexes commonly employed in catalysis demonstrated their confined nature. Despite their notable steric congestion, these complexes exhibited remarkable catalytic activities and unusual selectivities, both in nature and level, that make them unique in the field of synthetic homogeneous gold catalysis.

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Atomically precise gold clusters are highly desirable due to their well-defined structure which allows the study of structure-property relationships. In addition, they have potential in technological applications such as nanoscale catalysis. The structural, chemical, electronic, and optical properties of ligated gold clusters are strongly defined by the metal-ligand interaction and type of ligands. This critical feature renders gold-phosphine clusters unique and distinct from other ligand-protected gold clusters. The use of multidentate phosphines enables preparation of varying core sizes and exotic structures beyond regular polyhedrons. Weak gold-phosphorous (Au-P) bonding is advantageous for ligand exchange and removal for specific applications, such as catalysis, without agglomeration. The aim of this review is to provide a unified view of gold-phosphine clusters and to present an in-depth discussion on recent advances and key developments for these clusters. This review features the unique chemistry, structural, electronic, and optical properties of gold-phosphine clusters. Advanced characterization techniques, including synchrotron-based spectroscopy, have unraveled substantial effects of Au-P interaction on the composition-, structure-, and size-dependent properties. State-of-the-art theoretical calculations that reveal insights into experimental findings are also discussed. Finally, a discussion of the application of gold-phosphine clusters in catalysis is presented.

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We report the synthesis and properties of the much sought-after tris(1,1,3,3-tetramethylguanidinyl) phosphine P(tmg)3 , a crystalline, superbasic phosphine accessible through a short and scalable procedure from the cheap and commercially available bulk chemicals 1,1,3,3-tetramethylguanidine, tris(dimethylamino)-phosphine and phosphorus trichloride. The new phosphine exhibits exceptional electron donor properties and readily forms transition metal complexes with gold(I), palladium(II) and rhodium(I) precursors. The formation of zwitterionic Lewis base adducts with carbon dioxide and sulfur dioxide was explored. In addition, the complete series of phosphine chalcogenides was prepared from the reaction of P(tmg)3 with N2 O and the elemental chalcogens.

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Luminescent copper(I) complexes showing thermally activated delayed fluorescence (TADF) have developed to attractive emitter materials for organic light emitting diodes (OLEDs). Here, we study the brightly luminescent dimer Cu2Cl2(P∩N)2 (P∩N = diphenylphosphanyl-6-methyl-pyridine), which shows both TADF and phosphorescence at ambient temperature. A solution-processed OLED with a device structure ITO/PEDOT:PSS/PYD2: Cu2Cl2(P∩N)2/DPEPO (10 nm)/TPBi (40 nm)/LiF (1.2 nm)/Al (100 nm) shows warm white emission with moderate external quantum efficiency (EQE). Methods for EQE increase strategies are discussed.

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Upon stabilization by 5,6-bis(diisopropylphosphino)acenaphthene to form compound 1, the fugitive antimony (I) cation exhibited nucleophilic behavior towards coinage metals. Compound 1 was strategically synthesized at room temperature from SbCl3 , the bis(phosphine), and trimethylsilyl trifluoromethanesulfonate taken in a 1:2:3 ratio, whereby the bis(phosphine) plays the dual role of a reductant and a supporting ligand. The generation of 1 involves two-electron oxidation of the ligand to form a P-P bonded diphosphonium dication. Compound 1 was separated from this dication to give both products in pure form in moderate yields. Despite the overall positive charge, the SbI site in 1 was found to bind to metal centers, forming complexes with AuI , AgI and CuI . Compound 1 reduced CuII to CuI and formed a coordination complex with the resulting CuI species. The effects of the electron-rich bis(phosphine) and the constrained peri geometry in stabilizing and enhancing the nucleophilicity of 1 have been rationalized through computational studies.