Weixu Feng

Hetero-binuclear near-infrared (NIR) luminescent Zn–Nd complexes self-assembled from the benzimidazole-based ligands

With the compound [Zn(HL(1))(2)(Py)] (H(2)L(1)=2-(1H-benzo[d]imidazol-2-yl)-6-methoxyophenol), Py=pyridine) or [Zn(HL(2))(2)(Py)] (H(2)L(2)=2-(1H-benzo[d]imidazol-2-yl)-4-bromo-6-methoxyphenol) as the precursor, complexes [ZnLn(HL(1))(2)(Py)(NO(3))(3)] (Ln=Nd, 1; Ln=Gd, 2) or [ZnLn(HL(2))(2)(Py)(NO(3))(3)] (Ln=Nd, 3; Ln=Gd, 4) were obtained by the further reaction with Ln(NO(3))(3)·6H(2)O (Ln=Nd or Gd). The result of their photophysical properties shows that the strong and characteristic near-infrared (NIR) luminescence of Nd(3+) ions for complexes 1 and 3 with emissive lifetimes in microsecond range, has been sensitized from the excited state ((1)LC and (3)LC) of the benzimidazole-based ligands, and the involvement of heavy atoms (Br) at the ligand endows the enhanced NIR luminescent property.

Bis-15-crown-5-ether-pillar[5]arene K+-Responsive Channels

An artificial selective K+ channel is formed from the supramolecular organization on bis(benzo-15-crown-5- ether-ureido)-pillar[5]arene compound. This channel achieves a selectivity of SK+/Na+ = 5 for an initial transport rate of kK+ = 3.2 × 10-3 s-1. The cation-file diffusion occurs via selective macrocyclic-filters anchored on inactive supporting pillar[5]arene relays. The sandwich-type binding geometry of the K+ cation by two 15-crown-5 moieties sites is a key feature influencing channel efficiency.

Pyrene-box capsules for adaptive encapsulation and structure determination of unstable or non-crystalline guest molecules

“Pyrene-box” cages easily crystallize from aqueous solutions and readily encapsulate compounds of biological interest. These host–guest systems can be obtained under ambient conditions from 1,3,5,8-pyrenetetrasulfonate (PTS), guanidinium derivatives (G+) and biogenic guests bearing cationic groups. Out of the many examples of synthetic molecular capsules, Pyrene box cages are completely responding to the requirements of green chemistry: non-toxic, water soluble, cheap, commercially available compounds. The “Pyrene-Box” cages have been used for the in situ encapsulation of unstable or non-crystalline biogenic compounds, allowing the complete molecular structure determination of species that do not crystallize by themselves. The encapsulated guests have a reduced motional degrees of freedom which is obtained via their anchoring to the Pyrene box cages that allows at the same time to reduce a significant amount of disorder. In this highlight we discuss the recent developments of the encapsulation chemistry of the “Pyrene box” and the strategy behind its synthesis, together with further possible developments and the limitations of this biomimetic supramolecular cage system. The “Pyrene Box” shows great potential for future applications, ranging from fundamental studies of structure determination of unstable molecules to drug delivery vehicles.

Dynameric host frameworks for the activation of lipase through H-bond and interfacial encapsulation

A facile lipase activation has been achieved by direct addition of multivalent amide dynameric frameworks into the reaction aqueous solutions, through the combined effects of lipase-host matrices, H-bonds and interfacial interactions.

(E)-N'-(5-Bromo-2-hy-droxy-3-meth-oxy-benzyl-idene)-2-hy-droxy-benzohydrazide monohydrate.

The organic molecule of the title hydrate, C15H13BrN2O4·H2O, is roughly planar, with a mean deviation of 0.0939 (2) Å. The dihedral angle between the two aromatic rings is 8.2 (3)°. Intramolecular O—H⋯N and O—H⋯O hydrogen bonds are observed. In the crystal, N—H⋯O(water) and O(water)—H⋯O hydrogen bonds lead to a three-dimensional network.

Bis[μ-N'-(5-bromo-3-meth-oxy-2-oxido-benzyl-idene)-2-hydroxybenzohydra-zidato]bis[(N,N-dimethyl-formamide)-copper(II)].

The title compound, [Cu2(C15H11BrN2O4)2(C3H7NO)2], is derived from the reaction of N′-(5-bromo-2-hydroxy-3-methoxybenzylidene)-2-hydroxybenzohydrazide and copper nitrate in a dimethylformamide solution in the presence of sodium hydroxide. The compound can be regarded as a binuclear centrosymmetric complex. In the crystal, the CuII atom is fivefold surrounded and adopts a distorted square-pyramidal coordination environment. An intramolecular O—H⋯N hydrogen bond stabilizes the molecular conformation.

4-Bromo-2-meth­oxy-6-(1-phenyl-1H-benzimidazol-2-yl)phenol

The title compound, C20H15BrN2O2, crystallized with three independent molecules in the asymmetric unit. Intramolecular O—H⋯N hydrogen bonds induce coplanarity of the substituted benzene ring and the benzimidazole ring, with mean deviations from the planes of 0.0931 (10), 0.0448 (10) and 0.0083 (11) Å in the three molecules.