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The self-assembly of an amino-acid substituted tetraphenylethylene (TPE) into a hydrogen-bonded dimeric capsule and an aggregate is reported. Depending on the conditions applied they exhibit bluish photoluminescence with QYs up to 24%.

A wide range of functionalized pyridine ligands have been employed to synthesize a variety of Pd(II) complexes of the general formulas [Pd

C,N-cyclopalladated complexes are among the most robust and widely used (pre)catalysts of cross-coupling reactions, combining long shelf life with high catalytic activity. In this report, we describe synthesis and properties of new Pd(II) complexes of a flexidentate ligand – 2,2-dimethyl-5-(2-pyridyl)pentane-3,5-dione (HL). Its coordinating properties resulted in the formation of two stereoisomeric cis- and trans-PdL2 complexes each with one ligand in O,O- and the other in N,C(sp3)-coordination modes. The solid-state structures have been established by means of single-crystal X-ray diffraction methods and are retained in solution as indicated by NMR spectroscopy. Both these isomers proved to be efficient (pre)catalysts of phosphine-free Heck cross-coupling of iodoarenes with olefins.

A series of switchable polymeric materials based on Ag(i), Pd(ii) and Pt(ii) and ambidentate ligand has been synthesized and showed enhanced catalytic activity in Heck reaction in comparison with their mononuclear counterparts.

Hydrogen-bonded polymers are a class of highly dynamic supramolecular aggregates, whose self-assembly may be tuned by very mild external or internal stimuli. However, the rational design of chiral supramolecules remains challenging especially when flexible components are involved. The combination of the inherent weakness and dynamic nature of the intermolecular bonds that hold together such assemblies with unrestricted molecular motions introduces additional factors which may affect the self-assembly process. In this report the self-assembly of four amino acid-derived chiral biphenyldiimides into open-chain 1D supramolecular polymers is presented. While the primary driving force, COOH···HOOC hydrogen bonding, is responsible for the polymer growth in all cases, the amino acid side chains play an important role in either stabilizing or destabilizing the assemblies obtained, as deduced from studies of the thermodynamics of the self-assembly process. Furthermore, substantial differences in the structural factors governing the polymerization process between dynamic liquid and static solid are found. This work demonstrates the potential of the rather unexplored class of diimide-based organic dyes in the formation of well-organized chiral supramolecular assemblies with tunable properties.

We report the implementation of coordination complexes containing two types of cationic moieties, i. e. pyridinium and ammonium quaternary salt, as potential inhibitors of human cholinesterase enzymes. Utilization of ligands containing NNO-coordination site and binding zinc metal ion allowed mono- and tetra-nuclear complexes to be obtained with corner and grid structural type, respectively, thus affecting the overall charge of the compounds (from +1 to +8). We were able to examine for the first time the multivalency effect of metallosupramolecular species on their inhibitory abilities towards acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Importantly, resolution of the crystal structures of the obtained enzyme-substrate complexes provided a better understanding of the inhibition process at the molecular level.

A range of morphologically distinct metallosupramolecular Cu(II) and Pd(II) complexes has been constructed, based on the tritopic ligand 1,1',1″-(benzene-1,3,5-triyl)tris(4,4-dimethylpentane-1,3-dione) (H). By control of the reaction conditions, it is possible to generate distinct coordination assemblies possessing either macrocyclic or polymeric structures and more importantly distinct activity in catalysis of the Suzuki-Miyaura cross-coupling.

Here we report the simultaneous formation of doubly and triply dynamic libraries as a result of exchange reactions between functionalized organic building blocks. A combination of three different reversible covalent linkages involving a boronate ester transesterification along with an imine and disulfide exchange was employed to generate a new type of fully organic triply dynamic molecular assembly.

The molecular components of biological systems self-sort via different mechanisms to act in a cooperative manner and to avoid interfering with each other. Herein we describe mechanistic insights and a versatile strategy for the synthesis of water-soluble, pseudopeptide molecular cages based on disulfide bonds. The use of trifunctional thiols led to a dynamic combinatorial library (DCL) of readily isolable, multi-component homo and hetero cage-like architectures showing a degree of self-sorting related to the symmetry and size of the trithiol. The work provided detailed kinetic studies and DFT molecular modeling giving original insights into the disulfide cages' properties. We also applied the selected cage system in the fluorometric detection of La3+ cations, which led to the generation of a strongly luminescent metal–organic assembly.

Disruption of a tautomeric equilibrium by coordination self-assembly depends upon a delicate interplay between supramolecular interactions but has not been studied for supramolecular polymers in two dimensions at the solid–liquid interface. Presented herein is the description of a functionalized molecular module which in DMSO solution generates a highly compact dynamic aggregate in its lactam (amide) form that undergoes reaction with Zn(II) ion to give a ML2-type complex in which one lactam unit on each ligand has been converted to its iminol form, enabling bidentate binding also involving pyrimidine-N. These solution measurements, as well as a study by scanning tunneling microscopy at the liquid/graphite interface, corroborated by density functional studies, have revealed how the tautomeric equilibrium can be modulated by the addition of a metal salt.

Generation of well-defined organic-inorganic hybrid materials with controllable size and morphology is challenging and an active area of modern research in view of their unique properties and thus multifunctional applications. Specifically polyoxometalates (POMs) were recognized as a very promising group for the construction of those systems, nonetheless there are domains where the profound understanding of hierarchical mutual interactions and assembly are lacking. We present an efficient approach towards the synthesis of a novel group of POM-based nanocomposites that we name Complex-Decorated Surfactant Encapsulated-Clusters (CD-SECs). In the investigated system the organic surfactant may behave as a metal-coordinating agent, thus allowing for derivatization of the synthesized SECs via utilization of the non-covalent interactions. We demonstrate possibilities and limitations of three types of hybrid systems (H1-H3) generated via seven distinct constructing approaches (routes A-G). These systems have the potential to exhibit multiresponsive functions depending on the nature of their building blocks and could find many potential applications in biology or materials science.

Here, we report a reaction cascade employing the substituent-induced post-assembly modification of a Co(iii) complex. Unexpectedly, we found that the (triisopropylsilyl)alkynyl moiety introduced to the Sonogashira reaction with the bromo-functionalized Co(iii) assembly plays a "Trojan horse" role, triggering a subsequent, second step of the cascade, i.e. Co(iii) to Co(ii) reduction. The reported substituent-activated Sonogashira-redox cascade reaction might set a new direction in the construction of specific chemical sensors.

We describe here an unorthodox approach to dynamic covalent chemistry in which the initially-unexpected in-situ hydrolysis of a bis-imide is employed to control the composition of a library of structurally diverse macrocycles. A single building block is used to generate a library of numerous disulfide-based architectures in a one-pot single-step process. The dual-stimuli method is based on simultaneous changes in pH and DMSO concentration to expand the structural diversity of the macrocyclic products. Mechanistic details of this complex process are investigated by the kinetics analysis. We delivered a facile strategy for the synthesis of water-soluble, multicomponent and dynamic macrocycles equipped with number of different functional groups, thus giving a prospect of their application in guest-driven phase transfer.

The reaction between ionic liquid [Cat]+Cl− (where Cat stands for 1-butyl-3-methylimidazolium, 1-butyl-2,3-dimethylimidazolium or 1-butyl-4-methylpyridinium) and the metal precursor ([PtCl2(cod)], PtCl4, K2[PtCl4] or K2[PtCl6]) yielded two groups of derivatives: [Cat]+[PtCl4]− and [Cat]+[PtCl6]−, which formally are counted among halometallate ionic liquids, however, due to their high melting points they should be classified into anionic platinum complexes rather than into ionic liquids. All the derivatives were isolated and characterized spectroscopically (NMR, ESI-MS) and crystallographic structures were determined for three derivatives: ([BMPy]2[PtCl4], [BMIM]2[PtCl6] and [BMMIM]2[PtCl6]. Moreover, their melting points were measured and thermal stability was assessed. The above derivatives were employed as catalysts for hydrosilylation of olefins with diverse properties. All the studied catalysts showed high activity and their insolubility in the reaction medium made easy their isolation and multiple use in subsequent catalytic runs. The most effective catalysts did not lose their activity even after ten runs, thereby they make a very good alternative to commonly used homogeneous catalysts. Their simple synthesis and stability make them interesting both for economic and ecological reasons.

Two new air- and water-stable Pt(II) metallosupramolecular complexes based on ambidentate ligands have been designed, synthesized and fully characterized. The structure of complexes has been determined by various analytical techniques including NMR spectroscopy and TOF-MS. Additionally, the single crystal structure of 2 was determined by X-ray diffraction. The catalytic activity of these complexes in hydrosilylation has been investigated, establishing that both have similar high activity and selectivity within a broad scope of structurally distinct olefins and hydrosilanes.

Self-assembling macrobicyclic cryptand-type organic cages display remarkable self-sorting behavior with efficient component selection. Making use of the dynamic covalent chemistry approach, eight different cages were synthesized by condensation of tris(2-aminopropyl)amine with structurally different dialdehydes. A series of self-sorting experiments were first carried out on simple dynamic covalent libraries. They reveal the influence of different structural features of the aldehyde components on the condensation with two triamine capping units. Subsequently, self-sorting experiments were performed on more complex systems involving several dialdehyde building blocks. Altogether, the results obtained describe the effect of the presence of a heteroatom, of electrostatic interactions, of delocalization and of the flexibility/stiffness of the propensity of a component to undergo formation of a macrobicyclic cage. In the presence of a catalytic amount of acid, the macrobicyclic structure undergoes dynamic component exchange.

A range of morphologically distinct metallosupramolecular Cu(II) and Pd(II) complexes has been constructed, based on the tritopic ligand 1,1',1″-(benzene-1,3,5-triyl)tris(4,4-dimethylpentane-1,3-dione) (H

The design of new composite materials using extreme biomimetics is of crucial importance for bioinspired materials science. Further progress in research and application of these new materials is impossible without understanding the mechanisms of formation, as well as structural features at the molecular and nano-level. It presents a challenge to obtain a holistic understanding of the mechanisms underlying the interaction of organic and inorganic phases under conditions of harsh chemical reactions for biopolymers. Yet, an understanding of these mechanisms can lead to the development of unusual—but functional—hybrid materials. In this work, a key way of designing centimeter-scale macroporous 3D composites, using renewable marine biopolymer spongin and a model industrial solution that simulates the highly toxic copper-containing waste generated in the production of printed circuit boards worldwide, is proposed. A new spongin–atacamite composite material is developed and its structure is confirmed using neutron diffraction, X-ray diffraction, high-resolution transmission electron microscopy/selected-area electron diffraction, X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure spectroscopy, and electron paramagnetic resonance spectroscopy. The formation mechanism for this material is also proposed. This study provides experimental evidence suggesting multifunctional applicability of the designed composite in the development of 3D constructed sensors, catalysts, and antibacterial filter systems.

Metal-organic assemblies have received significant attention for catalytic and other applications, including gas and energy storage, due to their porosity and thermal/chemical stability. Here, we report the synthesis and physicochemical characterization of three metallosupramolecular assemblies consisting of isomeric ambidentate pyridyl-&beta, diketonate ligands L1&ndash, L3 and Cu(II) metal ions. It has been demonstrated that the topology and dimensionality of generated supramolecular aggregates depend on the location of the pyridine nitrogen donor atom in L1&ndash, L3. This is seen in characterization of two distinct 2D polymeric assemblies, i.e., [Cu(L1)2]n and [Cu(L2)2]n, in which both &beta, diketonate and pyridine groups are coordinated to the Cu(II) center, as well as in characterization of the mononuclear 1D complex Cu(L3)2, in which the central atom is bound only by two &beta, diketonate units.

A bifunctional molecule containing both a bidentate binding site for metal ions and an aminopyrimidine H-bond donor-acceptor site has been synthesized, and its properties, in its free and coordinated forms, have been established in solution and in the solid state by analytical and spectroscopic methods as well as by X-ray structure determinations. Structural characterization has shown that it forms a one-dimensional H-bonded polymeric assembly in the solid state, while spectroscopic measurements indicate that it also aggregates in solution. The reaction of a simple Fe(II) salt with this assembly results in the emergence of two geometrical isomers of the complex: [FeL3](BF4)2·9H2O-C1 (meridional, mer) and [FeL3]2(SiF6)(BF4)2·12H2O-C2 (facial, fac). While, complex C1 in the solid state generates a one-dimensional H-bonded polymer involving just two ligands on each Fe center, with the chirality of the complex units alternating along the polymer chain, the structure of complex C2 shows NH···N interactions seen in both the ligand and mer complex (C1) structures to be completely absent. Physicochemical properties of the free and complexed ligand differ substantially.

We report the implementation of coordination chemistry onto the generation of new types of metallosupramolecular complexes with laterally appended cationic moieties for DNA binding in buffered aqueous media. Utilization of an N,N,O-type coordination pocket along with an octahedral zinc(II) metal ion allowed us to obtain mono- and tetranuclear complexes in both solution and solid state, as confirmed by NMR spectroscopy and single-crystal X-ray diffraction, respectively. By using isothermal titration calorimetry and gel electrophoresis, multiply charged cationic assemblies were observed to effectively bind to DNA through multivalent electrostatic interactions. Furthermore, we observed a correlation between the multivalency of the compounds employed and the effectiveness of DNA binding.

We report herein a facile and widely applicable microwave-assisted protocol for the synthesis of symmetrical diimides based on three structurally distinct aromatic dianhydrides: pyromellitic (PMA), biphenyl-tetracarboxylic acid (BPDA) and benzophenone-tetracarboxylic (BTDA) and five natural amino acids (Phe, Tyr, Ile, Lys, Cys). Fifteen symmetrical diimides with different structural characteristics containing a variety of functional groups can be produced with high yields and on a large scale.

The Pd(II) complexes of the ambidentate pyridyldiketones 2,2-dimethyl-5-(3- or 4-pyridyl)pentane-3,5-dione are readily prepared in their linkage isomeric forms by the appropriate pH control during syntheses. The isolated diketonate- or pyridine-bound species can be interconverted with essentially 100% efficiency by treatment with an acid or base, respectively. Under the normal basic conditions for a Suzuki-Miyaura coupling, only the diketonate forms are present and act as very efficient catalysts for this reaction. The dynamic nature of the presented complexes allows the catalytic process to be quenched and reactivated at any stage without the risk of losing the catalyst's activity.

To establish a background to the possible use of its ambidentate derivatives as stimulus-responsive ligands in functional complexes, the basic coordination chemistry of the anion derived from 4,4-dimethyl-1-phenylpentane-1,3-dione (benzoylpivaloylmethane, bpmH) has been re-examined with selected main group and transition metal M(II) and M(III) species. There is evidence that the steric bulk of the 1,3-dione substituents is not sufficient to prevent oligomerisation of the Ni(II) complex and equilibrium mixtures of geometric isomers can be detected in solution for at least the Al(III), Co(III) and Pd(II) complexes. Crystal structure determinations on both [Cu(bpm)2] and [Pd(bpm)2] show, however, that a single isomer can be isolated in the solid state.

International audience; Small π-conjugated molecules can be designed and synthesized to undergo controlled self-assembly forming low-dimensional architectures, with programmed order at the supramolecular level. Such order is of paramount importance because it defines the property of the obtained material. Here, we have focused our attention to four pyromellitic diimide derivatives exposing different types of side chains. The joint effect of different noncovalent interactions including π–π stacking, H-bonding, and van der Waals forces on the four derivatives yielded different self-assembled architectures. Atomic force microscopy studies, corroborated with infrared and nuclear magnetic resonance spectroscopic measurements, provided complementary multiscale insight into these assemblies.

The hierarchical self-assembly of l-tyrosine substituted naphthalenediimide has been explored in solution by NMR spectroscopy and in the solid-state by atomic force microscopy. Spontaneous non-covalent polymerisation led to the formation of a three-dimensional fibre-like supramolecular polymer with n-type semiconducting properties.

The functionalization of a spherical Keplerate-type polyoxometalate {Mo72V30} with a cationic azobenzene surfactant has been achieved through ionic self-assembly. The photoisomerisation reaction of this complex, which emerges in a light-triggered aggregation–disaggregation process, has been followed by 1H NMR spectroscopy, dynamic light scattering, absorption spectroscopy and scanning electron microscopy analyses.

Highlights• Copper-catalyzed arylation of aqueous ammonia from aromatic halides.• Synthesis of aniline derivatives.• Mild temperature conditions in the presence of ambidentate pyridyldiketone ligands.; International audience; Catalytic systems based on copper and simple ligands of ambidentate pyridyldiketone type were used in direct amination of aryl iodides and bromides with aqueous ammonia in one of the mildest conditions described in the literature, with reaction temperature ranging between 25 and 80 °C.

Noncovalent self‐assembly creates an effective route to highly sophisticated supramolecular polymers with tunable properties. However, the outcome of this assembly process is highly dependent on external conditions. In this work, a monomeric naphthalene diimide (NDI), designed to allow solubility in a wide range of solvents, can assemble into three distinct noncovalent supramolecular species depending on solvent composition and temperature. Namely, while the self‐assembly in chlorinated solvents yields relatively short, hydrogen‐bonded nanotubes, the reduction of solvent polarity changes the assembly outcome, yielding π–π stacking polymers, which can further bundle into a more complex aggregate. The obtained polymers differ not only in their global morphology but—more strikingly—also in the thermodynamics and kinetics of their supramolecular self‐assembly, involving isodesmic or two‐stage cooperative assembly with kinetic hysteresis, respectively. Ultimately, three distinct assembly states can be accessed in a single experiment.

Ambidentate ligand pyridyldiketones were used in combination with copper to catalyze amination of aryl halides under very mild temperatures with aqueous ammonia. This novel catalytic system allow efficient coupling in one of the smoothest conditions ever reported in literature.

This review provides a general overview of the development of fluorescent chemosensors based on closed three-dimensional architectures and highlights selected examples from research groups which have made a significant contribution to this field. The basic principles and challenges involved in the design of cage-like fluorescence chemosensors for a variety of guest molecules are covered. Particular attention is paid to the use of molecular and supramolecular fluorescent architectures for the detection of explosives/hazardous substances, aromatics and biologically active compounds.

Quaterpyridine (qtpy) ligands have found significant applications as N-heterocyclic scaffolds in self-assembly processes, in particular the formation of various metallosupramolecular architectures, limited, however, by difficulties in their synthesis. Recent progress in the preparative organic and organometallic chemistry of polypyridines has resulted in the elimination of the most serious drawbacks concerning qtpy synthesis, consequently giving rise to a renewed interest in this class of compounds. Herein, we endeavor to define the essential aspects of quaterpyridine chemistry and provide the reader with a perspective on the ways in which this field has begun to flourish.

Condensation of 1-methyl-2-imidazolecarboxaldehyde with 2-(1-methylhydrazinyl)pyridine results in the synthesis of new, tridentate Schiff-base ligand L , which readily reacts with CoCl 2 to form a monometallic [Co L Cl 2 ] complex that, upon reduction, functions as active hydrosilylation catalyst. The ligand and the [Co L Cl 2 ] catalyst have been characterized spectroscopically (MS, NMR, FTIR) and by single crystal X-ray diffraction techniques. The results of preliminary catalytic experimentation show that the cobalt complex can induce hydrosilylation and dehydrogenative silylation of olefins, depending upon the hydrosilane substrate used.

Consideration of the crystal structures of four new 2,2′;6′,2′′-terpyridine derivatives in terms of the weak lattice interactions which can be discerned through calculation of their Hirshfeld surfaces shows that despite the common feature of stacking of the near-planar aromatic entities, specific interactions beyond dispersion within the stacked arrays are relatively uncommon. This is in accord with what is seen in the same analysis of the structures of known analogues, which provides context for the present work. That this is not simply a consequence of the transoid array of the N-donors in these free ligands is seen from extension of the Hirshfeld surface analysis to the structures of protonated species where cisoid arrays are seen.

Two new Zn4L6 cages composed of diamine subcomponents containing either naphthalene diimide (NDI) or porphyrin moieties are described. Their structural differences allow these cages to exhibit distinct interactions with different chemical stimuli, yielding different supramolecular products. The electron-poor NDI subunits of the first cage were observed to thread through electron-rich aromatic crown-ether macrocycles, forming mechanically-interlocked species up to a [3]catenane, whereas the porphyrin ligands of the second cage interacted favourably with C70, causing it to be bound as a guest. When mixed, the two cages were observed to form a dynamic combinatorial library (DCL) of seven constitutionally distinct mixed-ligand Zn4L6 cages. The DCL was observed to reconstitute in opposing ways when treated with either the crown ether or C70: the electron-rich macrocycle templated the formation of heteroleptic catenanes, whereas C70 caused the DCL to self-sort into homoleptic structures.

Porous materials are widely used in industry for applications that include chemical separations and gas scrubbing. These materials are typically porous solids, although the liquid state can be easier to manipulate in industrial settings. The idea of combining the size and shape selectivity of porous domains with the fluidity of liquids is a promising one and porous liquids composed of functionalized organic cages have recently attracted attention. Here we describe an ionic-liquid, porous, tetrahedral coordination cage. Complementing the gas binding observed in other porous liquids, this material also encapsulates non-gaseous guests-shape and size selectivity was observed for a series of isomeric alcohols. Three gaseous chlorofluorocarbon guests, trichlorofluoromethane, dichlorodifluoromethane and chlorotrifluoromethane, were also shown to be taken up by the liquid coordination cage with an affinity that increased with their size. We hope that these findings will lead to the synthesis of other porous liquids whose guest-uptake properties may be tailored to fulfil specific functions.

We report on the characterization of two imine type ligands containing photoresponsive azobenzene units as side groups and their transition metal ions complexes. The ligands, both free and in their complexes undergo trans- > cis photoisomerization after irradiation with UV light, but binding of metal ions reduces both the photoisomerisation reaction rates and cis isomer concentrations in the photostationary states. The greatest diminution in the photoisomerisation rate was observed for the complex containing Cd(II), the heaviest among the various transition metal ions tested in this study.

This work describes, for the first time, the application of combined pressure and temperature stimuli in disulfide metathesis reactions. In the system studied, above a pressure of 0.2 GPa, equimolar amounts of symmetric disulfides bis 4-chlorophenyl disulfide [(4-ClPhS)2 ] and bis 2-nitrophenyl disulfide [(2-NO2 PhS)2 ] react to give the heterodimeric product 4-Cl-PhSSPh-2-NO2 . In contrast to experiments conducted in solution at atmospheric pressure or in mechanochemical experiments under ball-mill grinding conditions, there is no necessity to use a base or thiolate anion as a catalyst for the exchange reaction under investigated conditions. Single-crystal and powder X-ray diffraction revealed also that, despite the high-pressure conditions of this reaction, the heterodimeric-disulfide product unexpectedly crystallizes into the low-density polymorph A. This counterintuitive result contrasts with the high-pressure stability of the higher-density polymorph B, confirmed by its compression up to 2.8 GPa with no signs of a phase transition.

Cage compounds are very attractive structures for a wide range of applications and there is ongoing interest in finding effective ways to access such kinds of complex structures, particularly those possessing dynamic adaptive features. Here we report the accessible synthesis of new type of organic cage architectures, possessing two different dynamic bonds within one structure: hydrazones and disulfides. Implementation of three distinct functional groups (thiols, aldehydes and hydrazides) in the structure of two simple building blocks resulted in their spontaneous and selective self-assembly into aromatic cage-type architectures. These organic cages contain up to ten components linked together by twelve reversible covalent bonds. The advantage provided by the presented approach is that these cage structures can adaptively self-sort from a complex virtual mixture of polymers or macrocycles and that dynamic covalent chemistry enables their deliberate disassembly through controlled component exchange.

We report the synthesis and characterization of a coordination architecture with a Fe(II) center obtained by subcomponent self-assembly in water. The complex is based on very rare hemi-iminal ligands spontaneously generated from commercially available materials. The complex can be further transformed into another species by oxidation reaction of both the metal center and organic ligand.