Abstract Metal complexes of salen ligands are an important class compounds, and they have been widely studied in the past. Among their successful catalytic applications, synthesis cyclic carbonates by coupling reaction epoxides with CO 2 has received increased attention; this is mostly due to importance using a greenhouse gas as feedstock for useful molecules. Herein most relevant past present research surrounding topic presented.

ConspectusAs Pasteur noted more than 150 years ago, asymmetry exists in matter at all organization levels. Biopolymers such as proteins or DNA adopt one-handed conformations, a result of the chirality their constituent building blocks. Even level elementary particles, due to parity violation weak nuclear force. While origin homochirality living systems remains obscure, does possibility its connection with broken symmetries larger smaller length scales, centrality biomolecular structure is...

It is possible to control the geometry and composition of metallasupramolecular assemblies via aspect ratio their ligands. This point demonstrated for a series iron- palladium-based coordination cages. Functionalized clathrochelate complexes with variable ratios were used as rod-like metalloligands. A cubic Fe(II)8L12 cage was obtained from metalloligand an intermediate ratio. By increasing length or by decreasing width ligand, self-assembly process resulted in clean formation tetrahedral...

Abstract Salen‐Metall‐Komplexe bilden eine wichtige Klasse von Verbindungen und wurden in der Vergangenheit ausführlich untersucht. Zu ihren katalytische Anwendungen, die es großer Zahl gibt, zählt auch Synthese cyclischer Carbonate durch Kupplung Epoxiden mit CO 2 , das als Atmosphärengas ein attraktiver Rohstoff für technische Verfahren ist. Wir berichten hier über wichtigsten früheren aktuellen Forschungsarbeiten zu diesem Thema.

A new class of Fe(II)4L4 capsules, based upon a tritopic trialdehyde subcomponent, is reported. One such capsule was prepared diastereoselectively through the incorporation chiral amine residue. This displaced by an achiral one, while maintaining stereochemistry cage framework (99% ee); this retained its even after 4 days at 90 °C. Mechanistic studies indicate memory displayed to be result effective stereochemical communication between metal centers mediated rigid 3-fold-symmetric faces, in...

Low molecular weight gels are formed by the self-assembly of a suitable small molecule gelator into three-dimensional network fibrous structures. The gel properties determined fiber structures, number and type cross-links distribution fibers in space. Probing these structures is difficult. Many reports rely on microscopy dried (xerogels), where solvent removed prior to imaging. assumption made that this has little effect but it not clear always (or ever) valid. Here, we use angle neutron...

A strategy for light-powered guest release from a tetrahedral capsule has been developed by incorporating azobenzene units at its vertices. new Zn

A series of large, optically active Fe(4)L(6) cages was prepared from linear 5,5'-bis(2-formylpyridines) incorporating varying numbers (n = 0-3) oligo-p-xylene spacers, chiral amines, and Fe(II). When a cage constructed the ligand bridged by one p-xylene spacer 1) bulky amine, both homochiral Fe(2)L(3) helicate were observed to coexist in solution due delicate balance between steric factors. In contrast, when less amine used, only observed. case larger 2, 3), long-range (>2 nm)...

We report the covalent post-assembly modification of kinetically metastable amine-bearing FeII2L3 triple helicates via acylation and azidation. Covalent prevented their reorganization to thermodynamically favored FeII4L4 tetrahedral cages, thus trapping system at non-equilibrium helicate structure. This functionalization strategy also conveniently provides access a higher-order tris(porphyrinatoruthenium)–helicate complex that would be difficult prepare by de novo ligand synthesis.

Three Zn(II)4L4 coordination cages, assembled from trisiminopyridine ligands, exhibit differences in their guest-binding selectivities and reactivity with tris(2-aminoethyl)amine (tren), which enabled the design of a molecular network that responded distinct ways to different chemical signals. When two these cages were present solution together, one them was observed selectively encapsulate chloroform, other cyclohexane. The guests could be released sequentially, specified order defined by...

Three isomeric zinc bisporphyrins have been prepared by covalently linking together two aminoporphyrins with an isophthalic acid derivative. The porphyrins differ in the substitution pattern on meso phenyl groups, that is, ortho, meta, or para. Titrations carried out UV-visible and 1H NMR spectroscopy used to map stabilities stoichiometries of complexes formed 1,4-diazabicyclo[2.2.2]octane (DABCO) chloroform. ortho- meta-substituted form 1:1 intramolecular sandwich complexes....

Abstract The creation of isolated chirotopic environments that mimic enzyme binding pockets has been a long-term goal in supramolecular chemistry. Metal–organic cages with enclosed and defined inner spaces have proven useful for this purpose. Here, we provide review recent progress on understanding, controlling the transmission stereochemistry within [M4(L)6] [M4(L)4] tetrahedral cages.

We describe a new dipeptide hydrogel based on an oligophenylene vinylene core. After gelation, the initial network evolves, expelling solvent and resulting in syneresis. this process effects bulk properties of material.

Abstract We describe two component hydrogels with networks composed of self-sorted fibres. The gelators are based on 1,4-distyrylbenzene (OPV3) and perylene bisimide (PBI) units. Self-sorted gels can be formed by a slow decrease in pH, which leads to sequential assembly. demonstrate self-sorting NMR, rheology small angle X-ray scattering (SAXS). Photoconductive xerogels prepared drying these gels. wavelength response the xerogel is different that PBI alone.

Sei mein Gast: Ein System auf der Basis selbstorganisierter ZnII-Komplexe lässt sich durch äußere chemische Reize steuern. Die Komplexe enthalten einen C3-symmetrischen Liganden, eine einzigartige Dreifachhelix 1 bildet. Durch Substitution am Liganden wird in Doppelhelix 2 überführt, die im Unterschied zu Gastmoleküle aufnehmen kann.

A metal template approach affords in high yield a tetra-Zn(salphen) macrocycle (3) which shows strong and cooperative self-assembly mediated by the formation of Zn(salphen) dimer units held together via μ(2)-phenoxo interactions. binding mode for tetranuclear Zn(4) 3 is supported comparison UV-vis fluorescence titration data recorded when compared with respective mononuclear dinuclear model compounds. dilution experiments carried out its Pd(4) analogue 4, as well comparative TEM studies...

The rate of pH change does not affect the primary assembly a gelator, but control mechanical properties gel.

Covalently crosslinked nanogels are widely explored as drug delivery systems and sensors. Radical polymerization provides a simple, inexpensive, broadly applicable approach for their preparation, although the random nature of reaction requires careful study final chemical composition. We demonstrate how different reactivities monomers influence total degree incorporation into polymer matrix role played by experimental parameters in maximizing efficiency. Nanogels based on...

A modular and general synthetic method is disclosed for nonsymmetrical heterobimetallic bis-salphen structures starting from a series of synthetically convenient monometalated triimine precursors. This methodology permits the introduction various combinations metal ions within framework potentially useful in multifunctional materials.

The synthesis and characterisation of a novel dual stimuli-responsive nanogel, based on thermoresponsive <italic>N-n</italic>-propylacrylamide an <sc>l</sc>-proline monomer acting as pH-switcher, is reported here.

Abstract The derivation and application of a statistical mechanical model to quantify stereochemical communication in metal–organic assemblies is reported. factors affecting the within between metal stereocenters were experimentally studied by optical spectroscopy analyzed terms free energy penalty per “incorrect” amine enantiomer incorporated, coupling stereocenters. These intra‐ inter‐vertex constants are used track degree across range (employing different ligands, peripheral amines,...

The use of olefin metathesis as a construction tool for multimetallic salen-based structures is described. approach involves mono- and diallyl-functionalized metallosalen complexes that can be directly coupled by leading to dimetallic species or mixtures linear cyclic oligomers. bis-allyl Ni(salen) has been studied in detail. At high concentration it possible selectively obtain di-Ni rather than heavier oligomers while under dilute conditions are preferentially obtained. A mono-allyl...

We describe the formation of structured liquids and gels from a functionalised dipeptide based on tetraphenylethylene. Tetraphenylethylene is well-known to be able undergo aggregation-induced emission. use emission data understand behaviour in water under variety conditions. The forms viscous solutions at high pH. Gels can formed by pH-trigger, but syneresis occurs. Addition calcium salt also leads gel with slight syneresis. sodium chloride self-supporting material, this not true rheological...

Abstract A metal‐templated, stepwise approach toward fully nonsymmetrical bis‐metallosalphen complexes is described. The synthesis comprises the selective monometalation of diimine precursors and subsequent introduction second metal ion by using various salicylaldehyde reagents. In case a bis‐Zn(salen) derivative, presence different peripheral substituents on two metallosalen units gave rise to large difference in kinetic stability, which was used selectively demetalate more labile site....

Abstract The derivation and application of a statistical mechanical model to quantify stereochemical communication in metal–organic assemblies is reported. factors affecting the within between metal stereocenters were experimentally studied by optical spectroscopy analyzed terms free energy penalty per “incorrect” amine enantiomer incorporated, coupling stereocenters. These intra‐ inter‐vertex constants are used track degree across range (employing different ligands, peripheral amines,...