Axially Symmetric U−O−Ln‐ and U−O−U‐Containing Molecules from the Control of Uranyl Reduction with Simple f‐Block Halides

The reduction of U^VI uranyl halides or amides with simple Ln^II or U^III salts forms highly symmetric, linear, oxo‐bridged trinuclear U^V/Ln^III/U^V, Ln^III/U^IV/Ln^III, and U^IV/U^IV/U^IV complexes or linear Ln^III/U^V polymers depending on the stoichiometry and solvent. The reactions can be tuned to give the products of one‐ or two‐electron uranyl reduction. The reactivity and magnetism of these compounds are discussed in the context of using a series of strongly oxo‐coupled homo‐ and heterometallic poly(f‐block) chains to better understand fundamental electronic structure in the f‐block.     

Deuteration of Water Enables Self‐Organization of Phospholipid‐Based Reverse Micelles

Phospholipid‐based reverse micelles are composed of branched cylinders. Their branching points are known to attract themselves and to slide along branches. The rate of this sliding is governed by the lifetime of H(D)‐bonded water bridges between phospholipid molecules. This lifetime is increased when the water is deuterated. On condition that the water contains at least 40 D atoms %, water/dipalmitoylphosphatidylcholine (DPPC)/deuterated pyridine reverse micelles with the composition 1.1:1:250 (v/v) have been shown to self‐organize into a liquid crystal in the 310–316 K temperature range. The mechanism of this self‐organization is unraveled by following the FTIR and ¹H NMR spectra of more concentrated micelles upon heating. During the preparation of micelles, pyridine‐(D⁺)H⁺ ions are formed. They give rise to hydron transfers, under the influence of the DPPC electric charges, evidenced by two broad FTIR absorptions above (BB1) and below (BB2) the ν(C? O) stretch. These hydron transfers occur along strong (D⁺)H⁺ bonds of pyridinium ions with pyridine (BB1) and DPPC C?O groups (BB2). The proton transfers at the interface of micelles, relayed in the continuous pyridine medium, create a tenuous link between separated micelles, thus facilitating their organization. Upon heating, DPPC heads shrink and DPPC chains expand to make wedge‐shaped DPPC molecules. The micelles then change in shape: cylinders constrict and enclosed water drifts towards branching points, which swell. Branching points of neighboring micelles come into contact. Due to the deuteration of water these contacts are prolonged and H bonds are formed between DPPC molecules located in each branching point. Upon storage at 39 °C, these branching points fuse. The lateral diffusion of DPPC molecules becomes free, as evidenced by a narrowing of all ¹H NMR resonances. Upon further heating, reorganization into a liquid crystal occurs.     

Complexation‐Induced Supramolecular Assembly Drives Metal‐Ion Extraction

Combining experiment with theory reveals the role of self‐assembly and complexation in metal‐ion transfer through the water–oil interface. The coordinating metal salt Eu(NO₃)₃ was extracted from water into oil by a lipophilic neutral amphiphile. Molecular dynamics simulations were coupled to experimental spectroscopic and X‐ray scattering techniques to investigate how local coordination interactions between the metal ion and ligands in the organic phase combine with long‐range interactions to produce spontaneous changes in the solvent microstructure. Extraction of the Eu³⁺–3(NO₃^?) ion pairs involves incorporation of the “hard” metal complex into the core of “soft” aggregates. This seeds the formation of reverse micelles that draw the water and “free” amphiphile into nanoscale hydrophilic domains. The reverse micelles interact through attractive van der Waals interactions and coalesce into rod‐shaped polynuclear Eu^III‐containing aggregates with metal centers bridged by nitrate. These preorganized hydrophilic domains, containing high densities of O‐donor ligands and anions, provide improved Eu^III solvation environments that help drive interfacial transfer, as is reflected by the increasing Eu^III partitioning ratios (oil/aqueous) despite the organic phase approaching saturation. For the first time, this multiscale approach links metal‐ion coordination with nanoscale structure to reveal the free‐energy balance that drives the phase transfer of neutral metal salts.     

Effect of the Constrained Environment on the Interactions between the Surfactant and Different Polar Solvents Encapsulated within AOT Reverse Micelles

Herein, we report a study of the interactions between different nonaqueous polar solvents, namely, ethylene glycol (EG), propylene glycol (PG), glycerol (GY), dimethylformamide (DMF), and dimethylacetamide (DMA), and the polar heads of sodium 1,4‐bis‐2‐ethylhexylsulfosuccinate (AOT) in nonaqueous AOT/n‐heptane reverse micelles. The goal of our study is to gain insights into the unique reverse‐micelle microenvironment created upon encapsulation of these polar solvents. For the first time, the study is focused on determining which regions of the AOT molecular structure are involved in the interactions with the polar solvents. We use FTIR spectroscopy—a noninvasive technique—to follow the changes in the AOT C?O band and the symmetric and asymmetric SO₃^? vibration modes upon increasing the content of polar solvents in the micelles. The results show that GY interacts through H bonds with the SO₃^? group, thereby removing the Na⁺ counterions from the interface remaining in the polar core of the micelles. PG and EG interact through H bonds, mainly with the C?O group of AOT, penetrating into the oil side of the interface. Thus, they interact weakly with the Na⁺ counterion, which seems to be close to the AOT sulfonate group. Finally, DMF and DMA, encapsulated inside the reverse micelles, interact neither with the C?O nor with the SO₃^? groups, but their weakly bulk‐associated structure is broken because of the interactions with Na⁺. We suggest that DMF and DMA can complex the Na⁺ ions through their carbonyl and nitrogen groups. Hence, our results do not only give insights into how the constrained environment affects the bulk properties of polar solvents encapsulated within reverse micelles but—more importantly—they also help us to answer the tricky question about which regions of the AOT moiety are involved in the interactions with the polar solvents. We believe that our results show a clear picture of the interactions present at the nonaqueous reverse‐micelle interface; this is important because these media are interesting nanoreactors for heterogeneous chemistry, templates for nanoparticles, and models for membranes.     

Electrochemical and Spectroscopic Behaviour of Bis(2‐mercaptopyridine‐N‐oxide)oxovanadium(IV)

The complex [VO(MPO)₂] (MPO = deprotonated 2‐mercaptopyridine N‐oxide) was synthesized and characterized by IR spectroscopy. Its electrochemical behaviour was investigated by cyclic voltammetry in different organic solvents. The V^IV/V^V and V^IV/V^III couples could be identified. The nature of the electroactive species is strongly dependent on the solvent. The results are discussed in terms of a reaction mechanism describing the characteristics of the electron transfer processes and the involved chemical reactions, and the stability of the complex in each solvent was also determined. The electronic spectra of the investigated solutions gave additional support to the proposed mechanisms.     

Hydrogen‐Atom Abstraction Reactions by Manganese(V)– and Manganese(IV)–Oxo Porphyrin Complexes in Aqueous Solution

High‐valent manganese(IV or V)–oxo porphyrins are considered as reactive intermediates in the oxidation of organic substrates by manganese porphyrin catalysts. We have generated Mn^V– and Mn^IV–oxo porphyrins in basic aqueous solution and investigated their reactivities in C? H bond activation of hydrocarbons. We now report that Mn^V– and Mn^IV–oxo porphyrins are capable of activating C? H bonds of alkylaromatics, with the reactivity order of Mn^V–oxo>Mn^IV–oxo; the reactivity of a Mn^V–oxo complex is 150 times greater than that of a Mn^IV–oxo complex in the oxidation of xanthene. The C? H bond activation of alkylaromatics by the Mn^V– and Mn^IV–oxo porphyrins is proposed to occur through a hydrogen‐atom abstraction, based on the observations of a good linear correlation between the reaction rates and the C? H bond dissociation energy (BDE) of substrates and high kinetic isotope effect (KIE) values in the oxidation of xanthene and dihydroanthracene (DHA). We have demonstrated that the disproportionation of Mn^IV–oxo porphyrins to Mn^V–oxo and Mn^III porphyrins is not a feasible pathway in basic aqueous solution and that Mn^IV–oxo porphyrins are able to abstract hydrogen atoms from alkylaromatics. The C? H bond activation of alkylaromatics by Mn^V– and Mn^IV–oxo species proceeds through a one‐electron process, in which a Mn^IV–‐oxo porphyrin is formed as a product in the C? H bond activation by a Mn^V–oxo porphyrin, followed by a further reaction of the Mn^IV–oxo porphyrin with substrates that results in the formation of a Mn^III porphyrin complex. This result is in contrast to the oxidation of sulfides by the Mn^V–oxo porphyrin, in which the oxidation of thioanisole by the Mn^V–oxo complex produces the starting Mn^III porphyrin and thioanisole oxide. This result indicates that the oxidation of sulfides by the Mn^V–oxo species occurs by means of a two‐electron oxidation process. In contrast, a Mn^IV–oxo porphyrin complex is not capable of oxidizing sulfides due to a low oxidizing power in basic aqueous solution.     

A non‐oxo methanolate‐bridged divanadium(IV) complex with tris(2‐sulfanidylphenyl)phosphane ligands: synthesis,structural characterization and magnetic investigation

Vanadium chemistry is of interest due its biological relevance and medical applications. In particular, the interactions of high‐valent vanadium ions with sulfur‐containing biologically important molecules, such as cysteine and glutathione, might be related to the redox conversion of vanadium in ascidians, the function of amavadin (a vanadium‐containing anion) and the antidiabetic behaviour of vanadium compounds. A mechanistic understanding of these aspects is important. In an effort to investigate high‐valent vanadium–sulfur chemistry, we have synthesized and characterized the non‐oxo divanadium(IV) complex salt tetraphenylphosphonium tri‐μ‐<!?tlsb=‐0.11pt>methanolato‐κ⁶O:O‐bis({tris[2‐sulfanidyl‐3‐(trimethylsilyl)phenyl]phosphane‐κ⁴P,S,S′,S′′}vanadium(IV)) methanol disolvate, (C₂₄H₂₀P)[V^IV₂(μ‐OCH₃)₃(C₂₇H₃₆PS₃)₂]·2CH₃OH. Two V^IV metal centres are bridged by three methanolate ligands, giving a C2‐symmetric V₂(μ‐OMe)₃ core structure. Each V^IV centre adopts a monocapped trigonal antiprismatic geometry, with the P atom situated in the capping position and the three S atoms and three O atoms forming two triangular faces of the trigonal antiprism. The magnetic data indicate a paramagnetic nature of the salt, with an S = 1 spin state.     

Mechanistic disparity in the electron transfer reactions of thiosulfate with di‐μ‐oxo‐bis(1,4,8,11‐tetraazacyclotetradecane)‐dimanganese(III,IV) and di‐μ‐oxo‐bis(1,4,7,10‐tetraazacyclododecane)‐dimanganese(III,IV) complexes

A comparative kinetic study of the reactions of two mixed valence manganese(III,IV) complexes of macrocyclic ligands, [L¹Mn^IV(O)₂Mn^IIIL¹], 1 (L¹ = 1,4,8,11‐tetraazacyclotetradecane) and [L²Mn^IV(O)₂Mn^IIIL²], 2 (L² = 1,4,7,10‐tetraazacyclododecane) with thiosulfate has been carried out by spectrophotometry in aqueous buffer at 30°C. Reaction between complex 1 and thiosulfate follows a first‐order rate saturation kinetics. The pH dependency and kinetic evidences suggest the participation of two complex species of Mn^III(μ‐O)₂Mn^IV under the experimental conditions. Detailed kinetic study shows that reduction of 2 proceeds through an autocatalytic path where the intermediate (Mn^III)₂ species has been assumed to catalyze the reaction. The difference in the reaction mechanisms is ascribed to the difference in stability of the intermediate complex species, the evidence for which comes from the electrochemical behavior of the complexes and time dependent EPR spectroscopic measurements during the reduction of 2 . © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 36: 119–128, 2004     

Vanadium Speciation by XANES Spectroscopy: A Three‐Dimensional Approach

A library of X‐ray absorption near‐edge structure (XANES) spectroscopic data for V^V, V^IV and V^III complexes with a broad range of biologically relevant ligand has been used to demonstrate that three‐dimensional plots of key XANES parameters (pre‐edge and edge energies; pre‐edge and white line intensities) can be used for the prediction of V oxidation states and coordination numbers in biological or environmental matrices. The reliability of the technique has been demonstrated by re‐analysis of the published XANES data for a V^V‐dependent bromoperoxidase.     

Comparative Study of three Mononuclear Vanadium‐Aromatic 1, 2‐Diol Complexes: Structure,Characterization and Anti‐Proliferating Effects Against Cancer Cells

Three mononuclear vanadium complexes containing aromatic 1, 2‐diols (catechol and naphthalene‐2, 3‐diol) ligands,[V^IVO(cat)₂][1, 3‐HPDA]₂ · CH₃OH ( 1 ), [V^IVO(N‐2, 3‐D)₂][1, 3‐H₂PDA] ( 2 ), and [V^VO₂(N‐2, 3‐D)(1, 3‐HPDA)] · 1, 3‐PDA ( 3 ) (cat = catechol, N‐2, 3‐D = naphthalene‐2, 3‐diol, 1, 3‐PDA = 1, 3‐propanediamine) were synthesized and characterized by X‐ray diffraction, IR and UV/Vis spectroscopy, and cyclovoltammetry. X‐ray analysis reveals that the spatial frameworks of complexes 1 – 3 are all constructed by hydrogen bonds donated by [1, 3‐H_nPDA]ⁿ⁺ (n = 1, 2) cation, forming distinct chain structures. Complexes 1 and 2 are both in the non‐chiral form of VO(L)₂, but 2 crystallizes in the chiral space group (P6₅22), due to the symmetry element of spiral axis, whereas complex 3 contains both enantiomers of chiral VO₂(L₁)(L₂) units, but crystallizes in the non‐chiral space group (P$\bar{1}$ ). The electrochemical behavior of the three complexes is studied in comparison with that of the free ligands. Complex 1 shows a pair of potentials assigned to the redox behavior of vanadium, while complexes 2 and 3 exhibit no such redox potentials. Pharmaceutical screening of complexes 1 – 3 were carried out against three representative cancer cell lines: A‐549 (lung cancer), Bel‐7402 (liver cancer) and HCT (colonic cancer) by MTT [3‐(4, 5‐dimethylthiazoyl‐2‐yl)‐2, 5‐diphenyltetrazolium bromide] assay. The results show that the vanadium‐catechol complex 1 exhibits more obvious anti‐proliferating effects against the three cell‐lines, whereas the two vanadium‐N‐2, 3‐D complexes 2 and 3 basically display no such effects.     

The speciation of vanadium in human serum

A knowledge of the speciation of vanadium in human serum is essential for an understanding of the biotransformation of antidiabetic vanadium complexes in human blood and of how vanadium is transported to the target cells. Such information may be acquired by two completely different approaches: separation techniques and modeling calculations. This review focuses on the latter.The two major metal ion binders in human serum are apotransferrin (apoTf) and human serum albumin (HSA), the interactions of which with V^IVO and V^V are discussed in detail. A partially new model for HSA–V^IVO interactions is introduced, in which the two binding sites (one for two and one for one metal ion) compete not only with each other, but also with hydrolysis of the metal ion.Focus is also placed on the possibility and importance of ternary complex formation between V^IVO, serum proteins and drug candidate ligands (maltol (mal), 1,2-dimethyl-3-hydroxy-4(1H)-pyridinone (dhp), acetylacetone (acac) and picolinic acid, (pic)): the structures and formation constants of different ternary complexes reported by the different research groups are critically reviewed.The serum speciations for V^IVO and V^V are calculated through use of the most recent stability constants; at biologically relevant concentrations (～1 μM, but definitely <10 μM) the apoTf complexes predominate for both metal ions. This has the consequences that the primary role of the drug candidate ligands of the original complexes is a carrier function until the vanadium is taken up into the serum, and the vanadium ion itself is the active metabolite responsible for the antidiabetic effect.     

Electrochemical Reduction of Vanadium(V)‐Cupferron Complex,VO(cupf)2OH

Electrochemical reduction of vanadium(V) complex with cupferron (N‐nitroso‐N‐phenylhydroxylamine), V^VO(cupf)₂OH, has been studied by polarography in wide potential range to verify the catalytic mechanism of electroreduction of coordinated cupferron ligand. Reduction of the complex was studied in the concentration range from 2 ? 10^?5 M to 10^?3 M. Depending on the process conditions kinetics of catalytic reduction of coordinated cupferron is either controlled by adsorption step or governed by mixed control of diffusion and chemical reaction. Kinetic parameters of the reduction process are reported. Reduction of V^VO(cupf)₂OH complex is accompanied by adsorption and autoinhibition phenomena. V(II) ion in the surface bound complex of vanadium with cupferron catalyzes reduction of coordinated cupferronate ligands. In 1 mM solutions, the catalytic reduction of coordinated cupferron ligand shifts to more cathodic potentials due to formation of a monolayer of adsorbed vanadium(III)‐cupferron complexes. Reduction kinetics in the presence of tetraalkylammonium salt is consistent with multilayer cooperative adsorption of anionic vanadium(II)‐cupferron complex and tetraalkylammonium cations.     

A Non‐Heme Iron Photocatalyst for Light‐Driven Aerobic Oxidation of Methanol

Non‐heme (L)Fe^III and (L)Fe^III‐O‐Fe^III(L) complexes (L=1,1‐di(pyridin‐2‐yl)‐N,N‐bis(pyridin‐2‐ylmethyl)ethan‐1‐amine) underwent reduction under irradiation to the Fe^II state with concomitant oxidation of methanol to methanal, without the need for a secondary photosensitizer. Spectroscopic and DFT studies support a mechanism in which irradiation results in charge‐transfer excitation of a Fe^III?μ‐O?Fe^III complex to generate [(L)Fe^IV=O]²⁺ (observed transiently during irradiation in acetonitrile), and an equivalent of (L)Fe^II. Under aerobic conditions, irradiation accelerates reoxidation from the Fe^II to the Fe^III state with O₂, thus closing the cycle of methanol oxidation to methanal.     

Effect of the Cationic Surfactant Moiety on the Structure of Water Entrapped in Two Catanionic Reverse Micelles Created from Ionic Liquid‐Like Surfactants

The behavior of water entrapped in reverse micelles (RMs) formed by two catanionic ionic liquid‐like surfactants, benzyl‐n‐hexadecyldimethylammonium 1,4‐bis‐2‐ethylhexylsulfosuccinate (AOT‐BHD) and cetyltrimethylammonium 1,4‐bis‐2‐ethylhexylsulfosuccinate (AOT‐CTA), was investigated by using dynamic (DLS) and static (SLS) light scattering, FTIR, and ¹H NMR spectroscopy techniques. To the best of our knowledge, this is the first report in which AOT‐CTA has been used to create RMs and encapsulate water. DLS and SLS results revealed the formation of RMs in benzene and the interaction of water with the RM interface. From FTIR and ¹H NMR spectroscopy data, a difference in the magnitude of the water–catanionic surfactant interaction at the interface is observed. For the AOT‐BHD RMs, a strong water–surfactant interaction can be invoked whereas for AOT‐CTA this interaction seems to be weaker. Consequently, more water molecules interact with the interface in AOT‐BHD RMs with a completely disrupted hydrogen‐bond network, than in AOT‐CTA RMs in which the water structure is partially preserved. We suggest that the benzyl group present in the BHD⁺ moiety in AOT‐BHD is responsible for the behavior of the catanionic interface in comparison with the interface created in AOT‐CTA. These results show that a simple change in the cationic component in the catanionic surfactant promotes remarkable changes in the RMs interface with interesting consequences, in particular when using the systems as nanoreactors.     

Mixed Boron(III) and Phosphorous(V) Complexes of meso‐Triaryl 25‐Oxasmaragdyrins

Two unprecedented mixed B^III/P^V complexes of meso‐triaryl 25‐oxasmaragdyrins were synthesized in appreciable yields under mild reaction conditions. These unusual 25‐oxasmaragdyrin complexes containing one or two seven‐membered heterocyclic rings comprised of five different atoms (B, C, N, O, and P) were prepared by reacting B(OH)(Ph)‐smaragdyrin and B(OH)₂‐smaragdyrin complexes, respectively, with POCl₃ in toluene at reflux temperature. The products were characterized by HRMS and 1D‐ and 2D‐NMR spectroscopy. X‐ray crystallography of one of the mixed B^III/P^V smaragdyrin complexes indicated that the macrocycle is significantly distorted and contains a stable seven‐membered heterocyclic ring within the macrocycle. The bands in the absorption and emission spectra were bathochromically shifted with reduced quantum yields and singlet‐state lifetimes relative to the free base, meso‐triaryl 25‐oxasmaragdyrin. The mixed B^III/P^V complexes were difficult to oxidize but easier to reduce than the free base. The DFT‐optimized structure of the 25‐oxasmaragdyrin complex with two seven‐membered heterocycles indicated that it was a bicyclic spiro compound with two half‐chair‐like conformers. This was in contrast to the chair‐like conformation of the complex with a single seven‐membered heterocyclic ring. Moreover, incorporation of a second phosphate group in the former case stabilized the bonding geometry and resulted in higher stability, which was reflected in the bathochromic shift of the absorption spectra, more‐positive oxidation potential, and less‐negative reduction potential.     

Voltammetrische und spektroskopische Untersuchungen zur Komplexbildung von Vanadium(IV) und Vanadium(V) mit Carbonat

Voltammetric and Spectroscopic Investigation of Complexation of Vanadium(IV) and Vanadium(V) by Carbonate Solutions which contain in addition to vanadium(IV) or vanadium(V), respectively, a high excess of bicarbonate or carbonate were studied by voltammetric and spectroscopic methods. A reversible electrode reaction occurs in the pH range 7–8 in 1 M KHCO₃. While generating V^IV from V^V electrochemically a carbonate ligand is added to V^IV. Based on ESR parameter recorded at room temperature and 77 K the existence of a V^IV carbonato complex is suggested. A comparison of these ESR parameter with those of analogous V^IV complexes leads to conclusions in view of the structure of the V^IV carbonato complex. These structural suggestions are supported by the fact that V^IV and V^V form a mixed valent dimer in HCO₃^?/CO₂-buffer of pH 7.5. Such dimers can be formed only when one of the oxygens of the V^VO₂⁺ cis-dioxo unit is able to coordinate at a basal site in the V^IV-complex. Thus, conclusions regarding the arrangement of the carbonato ligands in the monomeric V^V complex are possible too. A comparison of the complexes which are formed by V^IV and V^V with carbonate and the adducts arising from the interaction of V^IV and V^V with transferrin reveals the similarities of the both redox couples.     

Syntheses,Structures, Photoluminescence,and Magnetism of a Series of Discrete Lanthanide Complexes based on 2,5‐Dichlorobenzoate and 1,10‐Phenanthroline

The syntheses and crystal structures of eight lanthanide complexes with formula [Ln(2,5‐DCB)_x(phen)_y] are reported, which are characterized via single‐crystal, powder X‐ray diffraction, elemental analysis, IR spectroscopy, thermogravimetric analysis, photoluminescence measurement, and DC/AC magnetic measurement. These eight complexes are isostructural, and possess a discrete dinuclear structure. The adjacent dinuclear molecules are linked by the hydrogen bonding interactions into a one‐dimensional (1D) supramolecular chain. The neighboring 1D chains are further extended into a two‐dimensional (2D) supramolecular layer by the π–π stacking interactions. The photoluminescent properties of complexes 1 (Nd^III), 2 (Sm^III), 3 (Eu^III), 5 (Tb^III), 6 (Dy^III), and 8 (Yb^III) were investigated. Magnetic investigations also reveal the presence of ferromagnetic interactions in complexes 4 (Gd^III), 6 (Dy^III), and 7 (Er^III). Additionally, complex 6 (Dy^III) demonstrates field‐induced slow magnetic relaxation behavior.     

Complex Formation of d‐Metal Ions at the Interface of TbIII‐Doped Silica Nanoparticles as a Basis of Substrate‐Responsive TbIII‐Centered Luminescence

The complex formation of d‐metal ions at the interface of Tb^III‐doped silica nanoparticles modified by amino groups is introduced as a route to sensing d‐metal ions and some organic molecules. Diverse modes of surface modification (covalent and noncovalent) are used to fix amino groups onto the silica surface. The interfacial binding of d‐metal ions and complexes is the reason for the Tb^III‐centered luminescence quenching. The regularities and mechanisms of quenching are estimated for the series of d‐metal ions and their complexes with chelating ligands. The obtained results reveal the interfacial binding of Cu^II ions as the basis of their quantitative determination in the concentration range 0.1–2.5 μM by means of steady‐state and time‐resolved fluorescence measurements. The variation of chelating ligands results in a significant effect on the quenching regularities due to diverse binding modes (inner or outer sphere) between amino groups at the interface of nanoparticles and Fe^III ions. The applicability of the steady‐state and time‐resolved fluorescence measurements to sense both Fe^III ions and catechols in aqueous solution by means of Tb^III‐doped silica nanoparticles is also introduced.     

A Multi‐action and Multi‐target RuII–PtIV Conjugate Combining Cancer‐Activated Chemotherapy and Photodynamic Therapy to Overcome Drug Resistant Cancers

Pt^II complexes are commonly used to treat cancer. To reduce their side effects and improve their pharmacological properties, Pt^IV complexes are being developed as prodrug candidates that are activated by reduction in cancer cells. Concomitantly, Ru^II polypyridine complexes have gained much attention as photosensitizers for use in photodynamic therapy due to their attractive characteristics. In this article, a novel Pt^IV–Ru^II conjugate, which combines cancer activated chemotherapy with PDT, is presented. Upon entering the cancer cell, the Pt^IV centre is reduced to Pt^II and the axial ligands including the Ru^II complex and phenylbutyrate are released. As each component has its individual targets, the conjugate exerts a multi‐target and multi‐action effect with (photo‐)cytotoxicity values upon irradiation up to 595 nm in the low nanomolar range in various (drug resistant) 2D monolayer cancer cells and 3D multicellular tumour spheroids.