Dehydrogenative homocoupling of primary alcohols to form
esters
and coupling of amines to form imines was accomplished using a class
of novel pincer ruthenium complexes. The reactivities of the ruthenium
pincer complexes for the direct coupling of amines to form imines
were enhanced by introducing an imine arm to the pincer ligand. Selective
oxidation of benzylamines to imines was achieved using aniline derivatives
as the substrate and solvent.
The electrostatic combination of a Keplerate cluster, [Mo(132)O(372)(CH(3)COO)(30)(H(2)O)(72)](42-) with cationic terminated poly(styrene) yields polyoxometalate-based supramolecular star polymers, which can further self-assemble into vesicular aggregates in CHCl(3)-MeOH mixed solvent.
Hydrogenation of esters under mild conditions was achieved using air-stable ruthenium PN 3 -pincer complexes containing an aminophosphine arm. High efficiency was achieved even in the presence of water. DFT studies suggest a bimolecular proton shuttle mechanism which allows H 2 to be activated by the relatively stable catalyst with a reasonably low transition state barrier.
The spherical micelle and vesicle composed of [PW12O40](3-) and poly(styrene-b-4-vinylpyridinium methyl iodide) are regarded as a model system to study spherical polymer brushes (SPBs) in solvents of various quality. The pure repulsions occur for the brush chains in the chloroform solution and chloroform/methanol mixture with a methanol volume ratio of 9.1%, where the grafted polystyrene chains have a relatively extended conformation. Further increase in the methanol concentrations leads to the presence of the intra/inter-brush van der Waals attractions. Transmission electron microscopy studies show that there is a coexistence of isolated and oligomeric SPBs and multi-SPB aggregates (MSAs) with the methanol content from 17% to 23%. Only MSAs are detected with the increasing methanol content. Both the corona and core shrink significantly in the isolated and oligomeric SPBs and MSAs. The full interpenetration of the grafted chains is observed between the cores in the oligomeric SPBs and MSAs.
Tetrafunctionalized calix[4]resorcinarene cavitands commonly serve as supramolecular scaffolds for construction of coordination-driven self-assembled capsules. However, due to the calix-like shape, the structural diversity of assemblies is mostly restricted to dimeric and hexameric capsules. Previously, we reported a spontaneous heteroleptic complexation strategy based on a pair of self-recognizable terpyridine-based ligands and Cd II ions. Building on this complementary ligand pairing system, herein three types of nanocapsules, including a dimeric capsule, a Sierpinśki triangular prism, and a cubic star, could be readily obtained through dynamic complexation reactions between a tetratopic cavitand-based ligand and various multitopic counterparts in the presence of Cd II ions. The dimeric capsular assemblies display the spacer-length-dependent self-sorting behavior in a four-component system. Moreover, the precise multicomponent selfassembly of a Sierpinśki triangular prism and a cubic star possessing three and six cavitand-based motifs, respectively, demonstrates that such self-assembly methodology is able to efficiently enhance architectural complexity for calix[4]resorcinarene-containing metallo-supramolecules.
Pincers do the trick: The conversion of ethanol to ethyl acetate and hydrogen was achieved using a pincer-Ru catalyst in a Pd-Ag membrane reactor. Near quantitative conversions and yields could be achieved without the need for acid or base promoters or hydrogen acceptors (see scheme).
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