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The tremendous importance of dirhodium paddlewheel complexes for asymmetric catalysis is largely the result of an empirical optimization of the chiral ligand sphere about the bimetallic core. It was only recently that a H(C)Rh triple resonance 103Rh NMR experiment provided the long‐awaited opportunity to examine – with previously inconceivable accuracy – how variation of the ligands impacts on the electronic structure of such catalysts. The recorded effects are dramatic: formal replacement of only one out of eight O‐atoms surrounding the metal centers in a dirhodium tetracarboxylate by an N‐atom results in a shielding of the corresponding Rh‐site of no less than 1000 ppm. The current paper provides the theoretical framework that allows this and related experimental observations made with a set of 19 representative rhodium complexes to be interpreted. In line with symmetry considerations, it is shown that the shielding tensor responds only to the donor ability of the equatorial ligands along the perpendicular principal axis. Axial ligands, in contrast, have no direct effect on shielding but may come into play via the electronic cis ${cis}$ ‐effect that they exert onto the neighboring equatorial sites. On top of these fundamental interactions, charge redistribution within the core as well as the electronic trans ${trans}$ ‐effect of ligands of different donor strengths is reflected in the recorded 103Rh NMR shifts. [ABSTRACT FROM AUTHOR]

For the last decades, the chemical reduction of Au3+ to Au0 has been widely employed to produce various gold nanostructures. In comparison with the fast reduction, the slow reduction is systematically investigated in this research to provide more insights to reveal intermediary process and further disclose the underlying mechanism for growing gold nanostructures by using a series of simple ligands with aldehyde groups as weak reducing agents. The different binding energies of ligands to Aun+ (n=3, 1 and 0) exhibit variable binding affinities in starting, intermediate, and final gold species. For example, formic acid has much stronger binding affinity to Au+ than Au3+, and thus Au+ intermediate is able to be stabilized/captured during slow reduction of Au3+. Upon the disproportionation of Au+ to Au0 and Au3+, formic acid has much stronger binding affinity to the newly formed Au0 than other ligands for the controlled formation of gold nanostructures. Meanwhile, the adsorption of ligands causes substantially decreased surface energies on different gold planes. There are much higher energies on {110} planes compared to the other two {111} and {100} planes with certain ratios in these energies, leading to morphological growth of gold nanosheets. In this paper, we experimentally demonstrate anisotropic growth of gold nanosheets by using various ligands with weak reducing and appropriate coordination capabilities, and further provide insights to understand their morphological growth mechanism behind. This synthetic strategy is successfully extended to prepare silver, palladium, and platinum nanoplates. Going for gold: A facile method has been developed to synthesize gold nanostructures and investigate their formation mechanism by using various ligands with weak reducing and appropriate coordination capabilities, providing insights to the underlying growth mechanism for the formation of intermediate Au+ during retarded reduction. The morphology of the anisotropic gold nanostructures is controlled by surface energies of ligand‐bound gold planes with certain energy ratios and binding affinities of ligands to Au0. [ABSTRACT FROM AUTHOR]

Colloidal quantum dot (QD) photocatalysts have the electrochemical and optical properties to be highly effective for a range of redox reactions. QDs are proven photo‐redox catalysts for a variety of reactions in organic solvents but are less prominent for aqueous reactions. Aqueous QD photocatalysts require hydrophilic ligand shells that provide long‐term colloidal stability but are not so tight‐binding as to prevent catalytic substrates from accessing the QD surface. Common thiolate ligands, which also poison many co‐catalysts and undergo photo‐oxidative desorption, are therefore often not an option. This paper describes a framework for the design of water‐solubilizing ligands that are in dynamic exchange on and off the QD surface, but still provide long‐term colloidal stability to CdS QDs. The binding affinity and inter‐ligand electrostatic interactions of a bifunctional ligand, aminoethyl phosphonic acid (AEP), are tuned with the pH of the dispersion. The key to colloidal stability is electrostatic stabilization of the monolayer. This work demonstrates a means of mimicking the stabilizing power of a thiolate‐bound ligand with a zwitterionic tail group, but without the thiolate binding group. [ABSTRACT FROM AUTHOR]

Well‐defined supramolecular interactions are a powerful tool to control the stereochemistry of a catalytic reaction. In this paper, we report a novel core motif for fluxional 2,2′‐biphenyl ligands carrying (S)‐amino acid‐derived interaction sites in 5,5′‐position that cause spontaneous enrichment of the Rax rotamer. The process is based on strong non‐covalent interlocking between interaction sites, which causes diastereoselective formation of a supramolecular ligand dimer, in which the axial chirality of the two subunits is dictated by the stereochemical information in the amino acid residues. The detailed structure of the dimer was elucidated by NMR spectroscopy and single‐crystal X‐ray analysis. Three different phosphorus‐based ligand types, namely a bisphosphine, a bisphosphinite and a phosphoramidite were synthesized and characterized. Whereas the first one was found to exist in a strongly weighted equilibrium, the two others each exhibited stereoconvergent behavior transforming into the diastereopure Rax rotamer. Enriched ligands were used in rhodium‐mediated asymmetric hydrogenation reactions of prochiral olefins in which very high enantioselectivities of up to 96:4 were achieved. [ABSTRACT FROM AUTHOR]

Abstract: Two heptanuclear discs, [Co7(L1)6(CH3O)6]2+ (Co7‐L1) and [Co7(L2)12](ClO4)2 (Co7‐L2), have been prepared by the reaction of [Co(H2O)6](ClO4)2 with Schiff base HL1 (HL1=2‐methoxy‐6‐[(methylimino)methyl]phenolate) or benzimidazole derivative HL2 (HL2=(1H‐benzo[d]imidazol‐2‐yl)methanolate), respectively, at room temperature. In contrast, the reaction of [Co(H2O)6](ClO4)2 with a mixture of the two ligands, having similar coordination ability but different shapes, resulted in the butterfly‐structured tetranuclear cobalt cluster [Co4(L1)2(L2)4](ClO4)2⋅2H2O (Co4). Electrospray ionization mass spectrometry (ESI‐MS) analysis in real time revealed the {Co1}→{Co2}→{Co4}→{Co7} stepwise assembly when a single ligand was employed, but when both ligands were used only {Co4} was obtained, an intermediate of the former reactions. Interestingly, ligand competition was evidenced in the assembly process of the reaction with two ligands; for example, [Co4(L1)4(L2)2]2+ and [Co4(L1)3(L2)3]2+ were the primary clusters observed at the beginning of the reaction, but [Co4(L1)2(L2)4]2+ was the final product. This observation suggests ligand exchange is taking place, and DFT calculations confirmed that these transformations were possible. By varying the ratio of ligands, the abundance of a certain species in the competitive reaction could be controlled. [ABSTRACT FROM AUTHOR]

Alkali‐metal ferrates containing amide groups have emerged as regioselective bases capable of promoting Fe−H exchanges of aromatic substrates. Advancing this area of heterobimetallic chemistry, a new series of sodium ferrates is introduced incorporating the bulky arylsilyl amido ligand N(SiMe3)(Dipp) (Dipp=2,6‐iPr2‐C6H3). Influenced by the large steric demands imposed by this amide, transamination of [NaFe(HMDS)3] (HMDS=N(SiMe3)2) with an excess of HN(SiMe3)(Dipp) led to the isolation of heteroleptic [Na(HMDS)2Fe{N(SiMe3)Dipp}]∞ (1) resulting from the exchange of just one HMDS group. An alternative co‐complexation approach, combining the homometallic metal amides [NaN(SiMe3)Dipp] and [Fe{N(SiMe3)Dipp}2] induces lateral metallation of one Me arm from the SiMe3 group in the iron amide furnishing tetrameric [NaFe{N(SiCH2Me2)Dipp}{N(SiMe3)Dipp}]4 (2). Reactivity studies support that this deprotonation is driven by the steric incompatibility of the single metal amides rather than the basic capability of the sodium reagent. Displaying synergistic reactivity, heteroleptic sodium ferrate 1 can selectively promote ferration of pentafluorobenzene using one of its HMDS arms to give heterotrileptic [Na{N(SiMe3)Dipp}(HMDS)Fe(C6F5)]∞ (4). Attempts to deprotonate less activated pyridine led to the isolation of NaHMDS and heteroleptic Fe(II) amide [(py)Fe{N(SiMe3)Dipp}(HMDS)] (5), resulting from an alternative redistribution process which is favoured by the Lewis donor ability of this substrate. [ABSTRACT FROM AUTHOR]

A novel bis(diphenylphosphino)methane (DPPM) functionalized amidine ligand (DPPM−C(N‐Dipp)2H) (Dipp=2,6‐diisopropylphenyl) was synthesized. Subsequent deprotonation with suitable alkali metal bases resulted in the corresponding complexes [M{DPPM−C(N‐Dipp)2}(Ln)] (M=Li, Na, K, Rb, Cs; L=thf, Et2O). The alkali metal complexes form monomeric species in the solid state, exhibiting intramolecular metal‐π‐interactions. In addition, a caesium derivative [Cs{PPh2CH2‐C(N‐Dipp)2}]6 was obtained by cleavage of a diphenylphosphino moiety, forming an unusual six‐membered ring structure in the solid state. All complexes were fully characterized by single crystal X‐ray diffraction, NMR spectroscopy, IR spectroscopy as well as elemental analysis. Furthermore, the photoluminescent properties of the complexes were thoroughly investigated, revealing differences in emission with regards to the respective alkali metal. Interestingly, the hexanuclear [Cs{PPh2CH2‐C(N‐Dipp)2}]6 metallocycle exhibits a blue emission in the solid state, which is significantly red‐shifted at low temperatures. The bifunctional design of the ligand, featuring orthogonal donor atoms (N vs. P) and a high steric demand, is highly promising for the construction of advanced metal and main group complexes. [ABSTRACT FROM AUTHOR]

Novel seven‐membered cyclic imine‐based 1,3‐P,N ligands were obtained by capturing a Beckmann nitrilium ion intermediate generated in situ from cyclohexanone with benzotriazole, and then displacing it by a secondary phosphane under triflic acid promotion. These "cycloiminophosphanes" possess flexible non‐isomerizable tetrahydroazepine rings with a high basicity; this sets them apart from previously reported iminophophanes. The donor strength of the ligands was investigated by using their P‐κ1‐ and P,N‐κ2‐tungsten(0) carbonyl complexes, by determining the IR frequency of the trans‐CO ligands. Complexes with [RhCp*Cl2]2 demonstrated the hemilability of the ligands, giving a dynamic equilibrium of κ1 and κ2 species; treatment with AgOTf gives full conversion to the κ2 complex. The potential for catalysis was shown in the RuII‐catalyzed, solvent‐free hydration of benzonitrile and the RuII‐ and IrI‐catalyzed transfer hydrogenation of cyclohexanone in isopropanol. Finally, to enable access to asymmetric catalysts, chiral cycloiminophosphanes were prepared from l‐menthone, as well as their P,N‐κ2‐RhIII and a P‐κ1‐RuII complexes. [ABSTRACT FROM AUTHOR]

The calculated Au38 cluster is represented in the middle of the cover picture, coated by the N ‐ heterocyclic carbenes (NHCs) presented in the paper. The falling binary code “01” illustrates that the Au38 clusters are issued from DFT calculations. Molecular bis(NHC) gold complexes obtained from the functionalization of the particles are represented around the cluster. An experimental 1H NMR solid ‐ state spectrum is shown in the lower part of the cover to remind the reader that the study combines experimental and computational approaches. More information can be found in the Full Paper by F. Tielens, F. Remacle, S. Richeter et al. on page 10446 ff. [ABSTRACT FROM AUTHOR]

A Chiral‐at‐Al aluminate can be prepared by the stepwise reaction of two different alcohols with the aluminate anion [EtAl(6‐Me‐2‐py)3]−. The method can also be used to prepare chiral‐at‐ligand aluminates and for the introduction of 3‐py and 4‐py functionalities into the aluminate framework through the selective and controlled substitution of one or two pyridine arms, thereby giving entry to new supramolecular chemistry. The cover represents the formation of such a rare example of a chiral‐at‐aluminum aluminate and it is also a tribute to the oneiric worlds of surrealist painter René Magritte. More information can be found in the Full Paper by R. García‐Rodríguez et al. on page 17019. [ABSTRACT FROM AUTHOR]

A new base metal iron‐cobalt dyad has been obtained by connection between a heteroleptic tetra‐NHC iron(II) photosensitizer combining a 2,6‐bis[3‐(2,6‐diisopropylphenyl)imidazol‐2‐ylidene]pyridine with 2,6‐bis(3‐methyl‐imidazol‐2‐ylidene)‐4,4′‐bipyridine ligand, and a cobaloxime catalyst. This novel iron(II)‐cobalt(III) assembly has been extensively characterized by ground‐ and excited‐state methods like X‐ray crystallography, X‐ray absorption spectroscopy, (spectro‐)electrochemistry, and steady‐state and time‐resolved optical absorption spectroscopy, with a particular focus on the stability of the molecular assembly in solution and determination of the excited‐state landscape. NMR and UV/Vis spectroscopy reveal dissociation of the dyad in acetonitrile at concentrations below 1 mM and high photostability. Transient absorption spectroscopy after excitation into the metal‐to‐ligand charge transfer absorption band suggests a relaxation cascade originating from hot singlet and triplet MLCT states, leading to the population of the 3MLCT state that exhibits the longest lifetime. Finally, decay into the ground state involves a 3MC state. Attachment of cobaloxime to the iron photosensitizer increases the 3MLCT lifetime at the iron centre. Together with the directing effect of the linker, this potentially makes the dyad more active in photocatalytic proton reduction experiments than the analogous two‐component system, consisting of the iron photosensitizer and Co(dmgH)2(py)Cl. This work thus sheds new light on the functionality of base metal dyads, which are important for more efficient and sustainable future proton reduction systems. [ABSTRACT FROM AUTHOR]

A new class of emissive cyclometallated IrIII−AuI complexes with a bis(diphenylphosphino) methanide bridging ligand was successfully synthesised from the diphosphino complex [Ir(N^C)2(dppm)]+ (1). The different gold ancillary ligand, a triphenylphosphine (2), a chloride (3) or a thiocytosine (4) did not reveal any significant effect on the photophysical properties, which are mainly due to metal‐to‐ligand charge‐transfer (3MLCT) transitions based on IrIII. However, the AuI fragment, along with the ancillary ligand, seemed crucial for the bioactivity in A549 lung carcinoma cells versus endothelial cells. Both cell types display variable sensitivities to the complexes (IC50=0.6–3.5 μM). The apoptotic pathway is activated in all cases, and paraptotic cell death seems to take place at initial stages in A549 cells. Species 2–4 showed at least dual lysosomal and mitochondrial biodistribution in A549 cells, with an initial lysosomal localisation and a possible trafficking process between both organelles with time. The bimetallic IrIII−AuI complexes disrupted the mitochondrial transmembrane potential in A549 cells and increased reactive oxygen species (ROS) generation and thioredoxin reductase (TrxR) inhibition in comparison with that displayed by the monometallic complex 1. Angiogenic activity assays performed in endothelial cells revealed the promising antimetastatic potential of 1, 2 and 4. [ABSTRACT FROM AUTHOR]

While the generation of aryl radicals by photoredox catalysis under reductive conditions is well documented, it has remained challenging under an oxidative pathway. Because of the easy photo‐oxidation of alkyl bis‐catecholato silicates, a general study of phenyl silicates bearing substituted catecholate ligands has been achieved. The newly synthesized phenyl silicates have been fully characterized, and their reactivity has been explored. It was found that, thanks to the substitution of the catecholate moiety, notably with the 4‐cyanocatecholato ligand, the phenyl radical could be generated and trapped. Computational studies provided a rationale for these findings. [ABSTRACT FROM AUTHOR]

This paper reports a small family of cationic surfactants designed to bind polyanions such as DNA and heparin. Each molecule has the same hydrophilic cationic ligand and a hydrophobic aliphatic group with eighteen carbon atoms with one, two, or three alkene groups within the hydrophobic chain (C18-1, C18-2 and C18-3). Dynamic light scattering indicates that more alkenes lead to geometric distortion, giving rise to larger self-assembled multivalent (SAMul) nanostructures. Mallard Blue and Ethidium Bromide dye displacement assays demonstrate that heparin and DNA have markedly different binding preferences, with heparin binding most effectively to C18-1, and DNA to C18-3, even though the molecular structural differences of these SAMul systems are buried in the hydrophobic core. Multiscale modelling suggests that adaptive heparin maximises enthalpically favourable interactions with C18-1, while shape-persistent DNA forms a similar number of interactions with each ligand display, but with slightly less entropic cost for binding to C18-3-fundamental thermodynamic differences in SAMul binding of heparin or DNA. This study therefore provides unique insight into electrostatic molecular recognition between highly charged nanoscale surfaces in biologically relevant systems. [ABSTRACT FROM AUTHOR]

The incorporation of functional groups into the cavity of discrete supramolecular coordination cages (SCCs) will bring unique functions and applications. Here, three dicarboxylate ligands (H2L1Cl, H2L2Cl and H2L3Cl) containing N‐heterocyclic carbene (NHC) precursors as linkers were introduced to construct SCCs by combining with two C3‐symmertic (CpZr)3(μ3‐O)(μ2‐OH)3 clusters as three‐connect vertices, resulted in a series of rugby‐like V2E3 (V=vertex, E=edge) type homoleptic cages (SCC‐1, SCC‐2 and SCC‐3). However, V4E6‐type tetrahedral cages (SCC‐4 and SCC‐5), incorporating six Au‐NHC moieties, were obtained when the corresponding NHC‐gold(I) functionalized ligands (H2L1Au, H2L2Au) were applied. For the first time, we present a trackable CpZr‐involved cage to cage conversion to generate a heteroleptic V2E3 cage (SCC‐6) from two homoleptic cages (SCC‐2 and SCC‐5) with different geometries of V2E3 and V4E6. The heteroleptic assembly SCC‐6 can also be formed upon a subcomponent displacement strategy. The structural transformation and reassembly processes were detected and monitored by 1H NMR spectroscopy and electrospray‐ionization mass spectrometry. The formation of heteroleptic assembly was further supported by single crystal X‐ray diffraction analysis. Moreover, homoleptic cage SCC‐2 possesses a trigonal bipyramidal cationic cavity allowing the encapsulation of a series of sulfonate anionic guests. [ABSTRACT FROM AUTHOR]

Optimizing C=N bond formation and C/N component exchange has major significance in Dynamic Covalent Chemistry (DCC). Imine and hydrazone generation from their aldehyde, amine and hydrazine components showed large accelerations in presence of AgOTf or Zn(OTf)2, up to 104 for the Zn(II)‐(p‐anisidine)imine complex. Zn(OTf)2 and auxiliary p‐anisidine together accelerated 630 times the formation of the Zn(II)‐hydrazone complex, revealing a strong synergistic effect, traced to very fast initial formation of the reactive Zn(II)‐imine complex presenting a C=N bond metallo‐activated towards reaction with the hydrazine component. Reactions involving more entities showed kinetically faster and thermodynamically simpler outputs due to dynamic competition within a mixture of higher complexity. Catalytic amounts of metal salts and auxiliary amine gave similar marked rate accelerations and turnover, indicating true catalysis. The synergistic effect achieved by combining metallo‐ and organo‐catalysis points to a powerful co‐catalysis strategy of bond‐formation in DCC through interconnected chemical transformations. [ABSTRACT FROM AUTHOR]

Targeting the interface between DNA quadruplex and duplex regions by small molecules holds significant promise in both therapeutics and nanotechnology. Herein, a new pharmacophore is reported, which selectively binds with high affinity to quadruplex–duplex junctions, while presenting a poorer affinity for G‐quadruplex or duplex DNA alone. Ligands complying with the reported pharmacophore exhibit a significant affinity and selectivity for quadruplex–duplex junctions, including the one observed in the HIV‐1 LTR‐III sequence. The structure of the complex between a quadruplex–duplex junction with a ligand of this family has been determined by NMR methods. According to these data, the remarkable selectivity of this structural motif for quadruplex–duplex junctions is achieved through an unprecedented interaction mode so far unexploited in medicinal and biological chemistry: the insertion of a benzylic ammonium moiety into the centre of the partially exposed G‐tetrad at the interface with the duplex. Further decoration of the described scaffolds with additional fragments opens up the road to the development of selective ligands for G‐quadruplex‐forming regions of the genome. [ABSTRACT FROM AUTHOR]

Metalloradicals are key species in synthesis, catalysis, and bioinorganic chemistry. Herein, two iron radical cation complexes (3‐E)GaCl4 [(3‐E).+ = [{(IPr)C(Ph)E}2Fe(CO)3].+, E = P or As; IPr = C{(NDipp)CH}2, Dipp = 2,6‐iPr2C6H3] are reported as crystalline solids. Treatment of the divinyldipnictenes {(IPr)C(Ph)E}2 (1‐E) with Fe2(CO)9 affords [{(IPr)C(Ph)E}2Fe(CO)3] (2‐E), in which 1‐E binds to the Fe atom in an allylic (η3‐EECvinyl) fashion and functions as a 4e donor ligand. Complexes 2‐E undergo 1e oxidation with GaCl3 to yield (3‐E)GaCl4. Spin density analysis revealed that the unpaired electron in (3‐E).+ is mainly located on the Fe (52–64 %) and vinylic C (30–36 %) atoms. Further 1e oxidation of (3‐E)GaCl4 leads to unprecedented η3‐EECvinyl to η3‐ECvinylCPh coordination shuttling to form the dications (4‐E)(GaCl4)2. [ABSTRACT FROM AUTHOR]

The hexacoordinated antimony(V) dication [(ppy)3Sb]2+ ([1]2+; ppy=2‐(2‐pyridyl)phenyl), stabilized by three intramolecular donor–acceptor interactions, has been isolated as its hexachloroantimonate salt [1][SbCl6]2, prepared by the oxidative addition of chlorine to the neutral stibine [(ppy)3Sb] (1), followed by the abstraction of chloride. Air‐stable [1][SbCl6]2 exhibits remarkable thermal stability and the three ppy ligands on the antimony atom are shown to be magnetically inequivalent in the 1H and 13C NMR spectra. A hexacoordinated, meridional octahedral bonding geometry has been determined for [1][SbCl6]2 by X‐ray crystallographic analysis. Theoretical calculations were performed to investigate why the meridional form was generated preferentially over the facial form. In addition, the dynamics of the ppy ligands were investigated by variable‐temperature 1H NMR spectroscopy. The potential to generate dications by using a single‐electron‐transfer reagent has also been investigated. The dication [1]2+ is the first [12–Sb–6]2+ chemical species to have been structurally determined. [ABSTRACT FROM AUTHOR]

Unexpected inversion‐symmetry breaking was observed in the order–disorder phase transitions of [M(acac)2(abco)2] (1; M=Co2+, 2; Ni2+, acac−=2,4‐pentanedionato, abco=1‐azabicyclo‐[2.2.2]‐octane=quinuclidine) during heating. The isostructural, transition‐free complexes [M(acac)2(cabco)2] (3; M=Co2+, 4; Ni2+, cabco=3‐chloro‐1‐azabicyclo‐[2.2.2]‐octane=3‐chloroquinuclidine) were also studied for comparison. Complexes 1 and 2 crystallized in ordered phases in the centrosymmetric I2/m space group at 100 K, whereas they crystallized in disordered phases in the non‐symmetric I2 space group at 300 K. The 60° step rotation disordering of the abco ligands was observed in the electron density maps of 1 and 2, which was consistent with the transition enthalpies estimated by differential scanning calorimetry (DSC). Gradual phase transitions were observed for 1 and 2 by DSC and powder X‐ray diffraction (PXRD) at approximately 225 K. The inversion‐symmetry disordering was likely induced by the local pseudo‐symmetry of the abco ligands, increasing from trigonal to hexagonal and the increased steric repulsion pathways among them. [ABSTRACT FROM AUTHOR]

To develop efficient adsorbent materials for storage and separation of C2H2, an unprecedented supercage MOF, [Me2NH2]⋅[Zn3(ALP)(TDC)2.5]⋅3.5DMF⋅2 H2O (1) was constructed through medicinal molecule allopurinol (ALP) and S‐containing 2,5‐thiophenedicarboxylic acid (H2TDC). 1 contains a novel linear trinuclear cluster that is composed by ALP and carboxylates and forms a final uncommon 5‐connected yfy topological framework. The framework possesses three types of interlinked cages decorated by rich functional sites, and reveals not only high adsorption capacity for C2H2 but also excellent selective separation for C2H2/CO2 and C2H2/CH4 at 298 K. Dynamic breakthrough experiments on C2H2/CO2 (1:1) mixture and C2H2/CH4 (1:1) mixture also demonstrated the potential of the material to separate C2H2 from CO2 or CH4 mixtures. Molecular simulations were also studied to identify the different CO2‐ and C2H2‐ binding sites in 1, such as carboxylate groups, S atoms and carbonyl groups. [ABSTRACT FROM AUTHOR]

E3 (E = Si, Ge, Sn) clusters can be stabilized via the coordination with different Lewis bases (L) like cyclic (alkyl)(amino) carbene (cAAC), N‐heterocyclic carbene (NHC), saturated NHC, mesoionic carbenes, trimethylamine, pyridine, phosphinine and trimethylphosphine. The Frontispiece depicts the main source of stabilization,namely, L→E σ‐donation and L←E π‐back‐donation in cAAC stabilized E3 complexes, the former being dominant. For more details, see the Full Paper by S. Pan, G. Frenking, G. Merino et al. on page 7463 ff. [ABSTRACT FROM AUTHOR]

In recognition of the key role played by integrins in several life‐threatening dysfunctions, the search for novel small‐molecule probes that selectively recognize these surface receptors is still open and widely pursued. Inspired by previously established aminoproline (Amp)‐RGD based cyclopeptidomimetics with attracting αVβ3 integrin affinity and selectivity, the design and straightforward synthesis of 18 new AmpRGD chemotypes bearing additional structural variants were herein implemented, to shift toward peptide‐like αVβ6 integrin targeted binders. The ligand competence of the synthesized products toward αVβ6 was evaluated in competitive binding assays on isolated receptors, and αVβ6/αVβ3 selectivity was determined for a subgroup of compounds, resulting in the identification of four very promising candidates. SAR considerations and docking simulations allowed us to appreciate the key structural features responsible for the observed activity. [ABSTRACT FROM AUTHOR]

A novel family of iridium catalysts stabilised by P,N-ligands have been introduced. The ligands are based on imidazo[1,5- b]pyridazin-7-amines and can be synthesised with a broad variety of substitution patterns. The catalysts were synthesised quantitatively from the protonated ligands and a commercially available iridium precursor. The catalysts mediate the alkylation of amines by alcohols under mild conditions (70 °C). In addition, the synthesis of quinolines from secondary or primary alcohols and amino alcohols is reported. This sustainable synthesis proceeds through the liberation of two equivalents of water and two equivalents of dihydrogen. The investigations indicate that catalysts suitable for hydrogen autotransfer or borrowing hydrogen chemistry might also be suitable for acceptor-less dehydrogenative condensation reactions. [ABSTRACT FROM AUTHOR]

Tetramethylaluminato/halogenido(X) ligand exchange reactions in half‐sandwich complexes [CpRLa(AlMe4)2] are feasible in non‐coordinating solvents and provide access to large coordination clusters of the type [CpRLaX2]x. Incomplete exchange reactions generate the hexalanthanum clusters [CpR6La6X8(AlMe4)4] (CpR=Cp*=C5Me5, X=I; CpR=Cp′=C5H4SiMe3, X=Br, I). Treatment of [Cp*La(AlMe4)2] with two equivalents Me3SiI gave the nonalanthanum cluster [Cp*LaI2]9, while the exhaustive reaction of [Cp′La(AlMe4)2] with the halogenido transfer reagents Me3GeX and Me3SiX (X=I, Br, Cl) produced a series of monocyclopentadienyl rare‐earth‐metal clusters with distinct nuclearity. Depending on the halogenido ion size the homometallic clusters [Cp′LaCl2]10 and [Cp′LaX2]12 (X=Br, I) could be isolated, whereas different crystallization techniques led to the aggregation of clusters of distinct structural motifs, including the desilylated cyclopentadienyl‐bridged cluster [(μ‐Cp)2Cp′8La8I14] and the heteroaluminato derivative [Cp′10La10Br18(AlBr2Me2)2]. The use of the Cp′ ancillary ligand facilitates cluster characterization by means of NMR spectroscopy. [ABSTRACT FROM AUTHOR]

Complexes containing odd‐electron Be−Be bonds are still rare until now. Hereby, a series of neutral di‐beryllium amidinate complexes containing a Be−Be bond were explored theoretically. The complexes with direct chelation with the Be2 dimer by the bidentate amidinate (AMD) ligands are always corresponding to their global minimum structures. The detailed bonding analyses reveal that the localized electrons of the Be−Be fragment can be adjusted by the amount of AMD ligands because each AMD ligand only takes one electron from the Be2 fragment. Meanwhile, the hybridization of the central Be atom also changes as the number of AMD ligands increases. In particular, the sp3‐hybridized single‐electron Be−Be bond is firstly identified in the tri‐AMD‐ligands‐chelated neutral D3h‐Be2(AMD)3 complex, which also possesses the higher stability compared to its monoanionic D3h‐Be2(AMD)3− and monocationic C3‐Be2(AMD)3+ analogues. Importantly, our study provides a new approach to obtain a neutral odd‐electron Be−Be bond, namely by the use of radical ligands through side‐on chelation. [ABSTRACT FROM AUTHOR]

Ligand‐based NMR techniques to study protein–ligand interactions are potent tools in drug design. Saturation transfer difference (STD) NMR spectroscopy stands out as one of the most versatile techniques, allowing screening of fragments libraries and providing structural information on binding modes. Recently, it has been shown that a multi‐frequency STD NMR approach, differential epitope mapping (DEEP)‐STD NMR, can provide additional information on the orientation of small ligands within the binding pocket. Here, the approach is extended to a so‐called DEEP‐STD NMR fingerprinting technique to explore the binding subsites of cholera toxin subunit B (CTB). To that aim, the synthesis of a set of new ligands is presented, which have been subject to a thorough study of their interactions with CTB by weak affinity chromatography (WAC) and NMR spectroscopy. Remarkably, the combination of DEEP‐STD NMR fingerprinting and Hamiltonian replica exchange molecular dynamics has proved to be an excellent approach to explore the geometry, flexibility, and ligand occupancy of multi‐subsite binding pockets. In the particular case of CTB, it allowed the existence of a hitherto unknown binding subsite adjacent to the GM1 binding pocket to be revealed, paving the way to the design of novel leads for inhibition of this relevant toxin. [ABSTRACT FROM AUTHOR]

The cytotoxicity of MeHg+ species is shown through strong binding with endogenous thiols such as cysteine (CysH) and glutathione (GSH) to form MeHgCys and MeHgSG complexes. A novel benzimidazole‐based thione molecule with N‐CH2CH2OH substituent has been discovered, which exhibits remarkable effect in converting MeHgCys and MeHgSG to water‐soluble HgS snanoparticles and releases the corresponding free thiol (CysH or GSH) via unusual ligand exchange reactions. For more information, see the Full Paper by Gouriprasanna Roy et al. on page 5696 ff. [ABSTRACT FROM AUTHOR]

Redox‐Active Sulphur Diimide Ligand Anion radicals of R−N=S=N−R have never been isolated or structurally characterized. In their Full Paper on page 1278 ff., N P. Gritsan, R. T. Boeré, P. W. Roesky, A. V. Zibarev, S. N. Konchenko et al. report the first Cp*2Ln complexes (Ln = Sm, Eu, Yb; R = NSiMe3) of sulphur diimides and demonstrate by exhaustive characterisation (X‐ray diffraction, EPR, UV‐Vis‐NIR spectroscopy, SQUID magnetometry and rigorous ab initio computational methods) that these powerful reducing agents transfer an electron to the coordinated thiazyl ligand. A brand new world of redox non‐innocent ligands has thus emerged on the horizon. [ABSTRACT FROM AUTHOR]

Electrocatalysis The Ru complex is set on its path, along which it must cross either a high mountain (EEC pathway) or a smaller hill (ECE pathway) to reach the glittering green palace where it can fulfill its goal of converting CO2 to CO. The sun shines brighter on the ECE path, which is alluring and less energy‐demanding. The complex can tread that path provided that its Ru heart has electrons (e−) pumped in (tBu on terpyridine), and that the CH3CN is easily removed. This is achieved by a CH3 group at the bipyridine, which pushes the bipyridine into the CH3CN with the force of a bull, thereby facilitating CH3CN dissociation from the complex. More information can be found in the Full Paper by S. Ott, S. Maji et al. on page 14870 ff. [ABSTRACT FROM AUTHOR]

Lanthanide Single‐Ion Magnets The adequate choice of the ligands coordinated to LnIII centres plays a key role in raising the effective energy barrier Ueff in SIMs. Thus, in homoleptic LnL3 complexes showing field induced SMM behaviour with low thermal eneygy barriers, when a tridentate N3‐phenanthroline tetrazolate ligand (L) is substituted by a β‐diketonate ligand (L’), Ueff increases significantly allowing to these new LnL2L’ complexes to behave as SMMs at zero field. More information can be found in the Full Paper by J. M. Herrera et al. on page 14548 ff. [ABSTRACT FROM AUTHOR]

The internal cavity size of a metallosupramolecular assembly can be tuned by thoughtful design of the ligand. This work reports the introduction of imidazo[1,5‐a]pyridine scaffolds in place of the conventional imidazol‐2‐ylidene moieties, which resulted in new molecular containers bearing significantly enlarged cavities. The new hexacarbene metal assemblies can easily accommodate a dimethylsulfoxide molecule as a molecular guest. This is the first study of a unique "host–guest" system featuring an organometallic cylinder‐like cage exclusively derived from poly‐NHC ligands. More information can be found in the Full Paper by Y.‐F. Han et al. on page 5472. [ABSTRACT FROM AUTHOR]

The graphic shows a DNA double helix rendered in PyMOL with some of the nucleotides substituted with the copper complexes (in surface dotted form) reported here. The complexes contain planar phenanthrene ligands and these are facing into the double helix as artificial base pairs. The tiles on the left refer to one of our complexes (Cu=copper, PHEN=phenanthroline, TPMA=tris‐(2‐pyridylmethyl)amine). For more information, see the Full Paper by A. Kellett et al. on page 221 ff. [ABSTRACT FROM AUTHOR]

Introduction of phosphine oxide ligands to Tb(hfa)3 complexes leads to control of the BEnT process. From Arrhenius analysis based on the temperature‐dependent emission lifetime measurements, the ΔEa and A values are smaller for the polynuclear TbIII complexes than for the mononuclear TbIII complexes. The difference in ΔEa and A values between poly‐ and mononuclear TbIII complexes are caused by the formation of different excited states. More information can be found in the Full Paper by Y. Hasegawa et al. on page 17719. [ABSTRACT FROM AUTHOR]

The Frontispiece shows two nanoclusters are induced by the change of the surface alkynyl structures. The alkynyl −C≡C−tBu gives rise to a more spherical surface shape in 1 (red background) while −C≡CC6H4‐p‐tBu to a flat shape in 2 (green backgroud). The red and green also represent their different crystal colors and different UV/Vis properties. There are also Cl (green ball) and dppf (purple ball) surrounding these structures, suggesting co‐protection by three types of ligands. For more information, see the Full Paper Y.‐M. Lin, Q.‐M. Wang et al. on page 16029 ff. [ABSTRACT FROM AUTHOR]

The X‐ray study on a single crystal of the butterfly‐like complex [{Pt(C^C*)(μ‐pz)}2] (1), containing a cyclometalated N‐heterocyclic carbene ligand as wings (HC^C*=1‐(4‐(ethoxycarbonyl)phenyl)‐3‐methyl‐1H‐imidazol‐2‐ylidene), showed three molecules in the asymmetric unit with intermetallic separations (Å) of 3.2294(4) (1A), 3.2834(4) (1B), and 3.1208(6) (1C). From the reaction of 1 with excess of CHI3 in the air and the sunlight, complex [{Pt(C^C*)(μ‐pz)I)}2] (2) (dPt−Pt=2.6079(2) Å) was obtained as the major product, while [IPt(C^C*)(μ‐pz)2Pt(C^C*)CHI2] (3) (dPt−Pt=2.6324(3) Å) was obtained as the major product under argon atmosphere in the dark. Experimental and theoretical investigations showed that an easily accessible radical‐like mechanism operates under thermal conditions, with dioxygen acting as an efficient radical (R.) scavenger. The oxidation of a Pt2(II,II) "butterfly" by CHI3 to give metal−metal bonded Pt2(III,III) compounds is described now for the first time. [{Pt(C^C*)(μ‐pz)}2] is the first "platinum‐butterfly" with a cyclometalated N‐heterocyclic carbene (C^C*) acting as wings, that has ever been oxidized by halocarbons. The control of the reaction conditions allowed to get almost selectively [{Pt(C^C*)(μ‐pz)I)}2] or [IPt(C^C*)(μ‐pz)2Pt(C^C*)CHI2] which were fully characterized. Experimental and theoretical investigations showed that an easily accessible radical‐like mechanism operates under thermal conditions. [ABSTRACT FROM AUTHOR]

Azocarboxamides occupy a special place among azo ligands owing to their versatility for metal coordination. Herein ruthenium complexes with two different azocarboxamide ligands that differ in the presence (or not) of a coordinating pyridyl heterocycle are presented. By making full use of the O,N(amide), N(azo), and N(pyridyl) coordinating sites, the first diruthenium complex that is bridged by an azo ligand containing two different binding pockets was obtained. Moreover, it was conclusively proven that, in the mononuclear complexes, oxidation at the ruthenium center leads to a complete change of coordination at the chelating binding pocket. The complexes were characterized by NMR spectroscopy, mass spectrometry, and single‐crystal X‐ray diffraction. Additionally, the mechanism of the aforementioned redox‐triggered change in the chelating binding pocket and the electronic structures of all the complexes were investigated by a combination of electrochemistry, UV/Vis/NIR/EPR spectroelectrochemistry, and DFT calculations. This is first instance in which a redox‐driven change in the complete chelating binding pocket has been observed in a ruthenium complex as well as with azo‐based ligands. These results thus show the potential of these versatile azocarboxamide ligands to act as redox‐driven switches with possible relevance to electrocatalysis. Join at the tip: Ruthenium complexes of azocarboxamide ligands with and without a coordinating pyridyl heterocycle were synthesized. By making full use of the O,N(amide), N(azo), and N(pyridyl) coordinating sites, the first diruthenium complex bridged by an azo ligand containing two different binding pockets was obtained. Moreover, in the mononuclear complexes, oxidation at the Ru center leads to a change in the coordination mode at the chelating binding pocket (see scheme). [ABSTRACT FROM AUTHOR]

Abstract: The complex trans‐[Pt(F)(SF3)(PCy3)2] (1) shows a diverse reactivity pattern at the SF3 ligand towards ethanol and Me3SiOEt. This led by deoxyfluorination or alcoholysis to the generation of platinum complexes bearing a metal‐bound S(O)F or S(OEt)2 group. For the latter reaction trans‐[Pt(F){S(F)(OEt)2}(PCy3)2] is suggested as an intermediate. In reactivity studies of trans‐[Pt(F)(SF2)(PCy3)2][BF4] the complex [Pt(F){S(F)(OEt)}(PCy3)2][BF4] was prepared, which does not react with ethanol. [ABSTRACT FROM AUTHOR]

Comprehensive studies on the coordination properties of tridentate nitrenium ‐ based ligands reveal general and versatile binding abilities to various transition metals. The generality of N ‐ heterocyclic nitrenium as a ligand and its electronic properties have been investigated both experimentally and computationally, as discussed by M. Gandelman et al. in their Full Paper on page 7099 ff. The cover picture shows how a wide variety of transition metals in various oxidation states can be “picked up” by tridentate nitrenium ligands to form complexes with potentially interesting properties (cover design by Igor Armiach). [ABSTRACT FROM AUTHOR]

The peculiar structure of the nanocluster, reported by P. W. N. M. van Leeuwen et al. in their Full Paper on page 16121 ff., consists of eighteen copper atoms and ten phosphinothiolate anions with a core of eight copper atoms, four additional atoms sticking out via bridging ligands, and on top and below the central core three atoms also glued to the cluster via bridging ligand interactions. The structure of the cluster is unusually “unorganized” compared to most other clusters, although it does have an inversion center. [ABSTRACT FROM AUTHOR]

Bis(pyrazolyl)methane copper peroxide complexes display tyrosinase‐like catalytic phenol hydroxylation activity. An exchange of the pyridinyl unit (background) by a methylimidazolyl unit (middle) enhances the catalytic activity. In turn, substituting the pyridinyl with a carboxymethyl group (foreground) enhances the stability and the catalytic activity in catalytic phenol hydroxylation. This makes the presented tyrosinase model the fastest catalytic model. Kinetic measurements reveal substrate‐binding behaviour and a biomimetic electrophilic reaction mechanism. DFT calculations show that the carboxymethyl substituent weakens the pyridinyl donor, which enhances the activity. For more details, see the Full Paper by S. Herres‐Pawlis et al. on page 12171 ff. [ABSTRACT FROM AUTHOR]

Coordination chemistry is a powerful method to synthesize supramolecular cages with distinct features that suit specific applications. This work demonstrates the synthesis of discrete, homochiral FeII2L3 cages via chirality‐driven self‐assembly. Specifically, the installation of chirality – at both the vertices and ligand backbones – allows the formation of discrete, homochiral FeII2L3 cages of different sizes via stereochemical control of the iron(II) centers. We observed that larger cages require multiple chiral centra (chiral ligands and vertices). In contrast, the formation of smaller cages is stereoselective with solely chiral ligands. The latter cages can also be formed from two chiral subcomponents, but only when they have matching chirality. Single‐crystal X‐ray diffraction of these smaller FeII2L3 cages revealed several non‐covalent interactions as a driving force for narcissistic chiral self‐sorting. This expected behavior was confirmed utilizing the shorter ligands in racemic form, yielding discrete, homochiral FeII2L3 cages formed in enantiomeric pairs. [ABSTRACT FROM AUTHOR]

Mercury‐197 m/g are a promising pair of radioactive isomers for incorporation into a theranostic as they can be used as a diagnostic agent using SPECT imaging and a therapeutic via Meitner‐Auger electron emissions. However, the current absence of ligands able to stably coordinate 197m/gHg to a tumour‐targeting vector precludes their use in vivo. To address this, we report herein a series of sulfur‐rich chelators capable of incorporating 197m/gHg into a radiopharmaceutical. 1,4,7,10‐Tetrathia‐13‐azacyclopentadecane (NS4) and its derivatives, (2‐(1,4,7,10‐tetrathia‐13‐azacyclopentadecan‐13‐yl)acetic acid (NS4‐CA) and N‐benzyl‐2‐(1,4,7,10‐tetrathia‐13‐azacyclopentadecan‐13‐yl)acetamide (NS4‐BA), were designed, synthesized and analyzed for their ability to coordinate Hg2+ through a combination of theoretical (DFT) and experimental coordination chemistry studies (NMR and mass spectrometry) as well as 197m/gHg radiolabeling studies and in vitro stability assays. The development of stable ligands for 197m/gHg reported herein is extremely impactful as it would enable their use for in vivo imaging and therapy, leading to personalized treatments for cancer. [ABSTRACT FROM AUTHOR]

The introduction of a phenolate pendant arm in place of an acetate on AAZTA‐ and DATA‐like ligands resulted in hepta‐ and hexadentate chelators able to form Ga(III) complexes with thermodynamic stability and kinetic inertness higher than that of other Ga(III) complexes based on the parent 6‐amino‐6‐methylperhydro‐1,4‐diazepine scaffold. In particular, the heptadentate AAZ3A‐endoHB with a phenolate arm on an endocyclic N‐atom shows a logKGaL of 27.35 and a remarkable resistance to hydroxide coordination up to basic pH (pH>9). This behaviour allows to also improve the kinetic inertness of the complex showing a dissociation half‐life (t1/2) at pH 7.4 of 76 h. Although also the hexadentate AAZ2A‐exoHB chelator forms a stable (logKGaL=24.69) and inert (t1/2=33 h at pH 7.4) Ga(III) complex, the 68Ga labelling showed a better radiochemical yield with AAZ3A‐endoHB, especially at room temperature. Thus, a bifunctional chelator of AAZ3A‐endoHB was synthesized bearing an isothiocyanate group that was conjugated to the N‐terminus of a c(RGD) peptide for integrin receptor targeting. Finally, the conjugate was successfully labelled with 68Ga isotope, and the resulting radiotracer tested for its stability in human serum and then in vivo for targeting B16‐F10 tumours with miniPET imaging. [ABSTRACT FROM AUTHOR]

The reaction of the Ru(PPh3)3Cl2 with HL1−3−OH (−OH stands for the oxime hydroxyl group; HL1−OH=diacetylmonoxime‐S‐benzyldithiocarbazonate; HL2−OH=diacetylmonoxime‐S‐(4‐methyl)benzyldithiocarbazonate; and HL3−OH=diacetylmonoxime‐S‐(4‐chloro)benzyl‐dithiocarbazonate) gives three new ruthenium complexes [RuII(L1−3−H)(PPh3)2Cl] (1–3) (−H stands for imine hydrogen) coordinated with dithiocarbazate imine as the final products. All ruthenium(II) complexes (1–3) have been characterized by elemental (CHNS) analyses, IR, UV‐vis, NMR (1H, 13C, and 31P) spectroscopy, HR‐ESI‐MS spectrometry and also, the structure of 1–2 was further confirmed by single crystal X‐ray crystallography. The solution/aqueous stability, hydrophobicity, DNA interactions, and cell viability studies of 1–3 against HeLa, HT‐29, and NIH‐3T3 cell lines were performed. Cell viability results suggested 3 being the most cytotoxic of the series with IC50 6.9±0.2 μM against HeLa cells. Further, an apoptotic mechanism of cell death was confirmed by cell cycle analysis and Annexin V‐FITC/PI double staining techniques. In this regard, the live cell confocal microscopy results revealed that compounds primarily target the mitochondria against HeLa, and HT‐29 cell lines. Moreover, these ruthenium complexes elevate the ROS level by inducing mitochondria targeting apoptotic cell death. [ABSTRACT FROM AUTHOR]

Abstract: The combination of the redox‐active mesogenic anion [NiII(Bdt)(BdtSQ)]− (Bdt=1,2‐benzenedithiolato; BdtSQ=1,2‐dithia‐semi‐benzoquinonato) with alkyl‐substituted ammonium cations afforded a series of redox‐active ionic complexes of the type [NR4][NiII(Bdt)(BdtSQ)] [R=nC16H33 (NC164Ni) and C8,10 (NC8,104Ni); C8,10=6‐octylhexadecyl] or [NMe2R2][NiII(Bdt)(BdtSQ)] [R=nC16H33 (NMe2C162Ni) and C8,10 (NMe2C8,102Ni)]. X‐ray crystallographic analyses of NMe2C162Ni and NC164Ni revealed the formation of cation‐dependent integrated ionic layers separated by interdigittated alkyl chains. Complexes NMe2C162Ni and NC164Ni commonly form crystalline phases at room temperature, whereas complexes NMe2C8,102Ni and NC8,104Ni, which contain branched alkyl chains, form a metastable mesophase and an amorphous phase at the same temperature, respectively. Furthermore, complexes NMe2C162Ni, NMe2C8,102Ni, and NC164Ni commonly form a smectic A phase (SmA) at 375, 317, and 342 K, respectively. For the four complexes, well‐defined cyclic voltammetry responses, derived from ligand‐based oxidation and reduction, were observed in solution and the condensed phases, that is, upon casting these complexes on an indium‐doped tin oxide working electrode. The present study demonstrates the tunability of the mesomorphism of ionic molecular assemblies composed of alkyl‐substituted quaternary ammonium cations, while maintaining the well‐defined redox responses of the anions even in the condensed phases. [ABSTRACT FROM AUTHOR]

Most ignition and initiation systems nowadays still contain poisonous chemicals such as lead styphnate and lead azide but also chromates and other compounds of high concern. Therefore, methylsemicarbazide (1, MSC), which can be prepared in a one-step reaction and in an extraordinary high yield of 95 %, has been evaluated as ligand in energetic coordination compounds. For the first time 25 new transition metal complexes (Mn2+, Ni2+, Co2+, Cu2+, and Zn2+) using methylsemicarbazide (1) as the ligand were prepared and comprehensively analyzed by, for example, XRD, IR, EA, UV/Vis and DSC/DTA/TGA. Many show a strong energetic character, which can be tuned by using different anions such as Cl−, SO42−, NO3−, ClO4−, picrate or styphnate. Selected compounds were additionally evaluated as lead-free primary explosives in initiation tests (nitropenta filled detonators) and in laser ignition systems. Especially compound 7 showed very promising results during these tests and could be a potential candidate for future applications. [ABSTRACT FROM AUTHOR]

We report the synthesis, post-functionalization, and redox behavior of two organically functionalized aggregates, [V6O7(OMe)9{(OCH2)3C−CH2N3}] and [V6O7(OMe)9{(OCH2)3C−NH2}]. All twelve μ2-oxo groups on the edges of the Lindqvist-type {V6O19} core were replaced by alkoxo ligands. The absence of a negative charge and the closed organic shell make these neutral mixed-valence compounds very stable towards hydrolysis and well soluble in almost all common organic solvents. These are important advantages over classical POMs. By post-functionalization through copper(I)-catalyzed Huisgen cycloaddition or imine formation, various organic moieties could be introduced. Even a well-soluble trimer composed of three hexanuclear vanadium units connected through an aromatic triimino core was synthesized and studied. The diverse redox behavior, the versatile reactivity, the good stability, and the excellent solubility make our vanadium compounds highly interesting for applications as building blocks in macromolecular chemistry as well as redox labels in biochemistry. [ABSTRACT FROM AUTHOR]

Ruthenium polypyridyl complexes have received widespread attention as potential chemotherapeutics in photodynamic therapy (PDT) and in photochemotherapy (PACT). Here, we investigate a series of sixteen ruthenium polypyridyl complexes with general formula [Ru(tpy)(N−N)(L)]+/2+ (tpy=2,2′:6′,2′′-terpyridine, N−N=bpy (2,2′-bipyridine), phen (1,10-phenanthroline), dpq (pyrazino[2,3-f][1,10]phenanthroline), dppz (dipyrido[3,2-a:2′,3′-c]phenazine, dppn (benzo[i]dipyrido[3,2-a:2′,3′-c]phenazine), pmip (2-(4-methylphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline), pymi ((E)-N-phenyl-1-(pyridin-2-yl)methanimine), or azpy (2-(phenylazo)pyridine), L=Cl− or 2-(2-(2-(methylthio)ethoxy)ethoxy)ethyl-β-d-glucopyranoside) and their potential for either PDT or PACT. We demonstrate that although increased lipophilicity is generally related to increased uptake of these complexes, it does not necessarily lead to increased (photo)cytotoxicity. However, the non-toxic complexes are excellent candidates as PACT carriers. [ABSTRACT FROM AUTHOR]

The [4+2] cycloaddition reaction between 2- pyrone and Me3Si-C≡P gives the corresponding 2-(trimethylsilyl)- λ3-phosphinine in good yields as a rather air and moisture stable, colorless oil. Insight into the regioselectivity of the pericyclic reaction was obtained with the help of deuterium- labeling experiments. The silyl-phosphinine acts as a ligand for the preparation of a Cu(I) and the first crystallographically characterized phosphinine-Ag(I) complex. The title compound was further used as a starting material for an alternative preparation of the parent phosphinine C5 H5P by means of protodesilylation with HCl. C5 H5P reacts with CuBr∙S(CH3 )2 to give an infinite Cu(I)Br coordination polymer. DFT calculations shed light on the influence of the -Si(CH3)3 group on the electronic properties of the aromatic phosphorus heterocycle. [ABSTRACT FROM AUTHOR]