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A redox-responsive hybrid of polyoxometalate and conducting oligomer including its self-assemblies with controllable morphologies are reported. To this end, a hybrid molecule, containing a Lindqvist hexamolybdate as the polar head group and N,N′-bis(4′-amino-2,6-dimethylphenyl)-1,4-quinonediimine as the redox-responsive and aggregating group, is prepared. This hybrid exhibits redox-responsive behavior with controllable assembling morphological transition from spherical vesicles to short cylindrical vesicles. Besides, the hybrid-based self-assemblies are transferred to the surface, thus the surface wettability can be well-tuned owing to the morphological transitions of the self-assemblies. By marrying conducting materials with polyoxometalate chemistry, this research opens a new horizon of polyoxometalate-based self-assembled systems with potential applications in functional materials. [ABSTRACT FROM AUTHOR]

Most state-of-art transition-metal catalysts usually require organic ligands, which are essential for controlling the reactivity and selectivity of reactions catalyzed by transition metals. However, organic ligands often suffer from severe problems including cost, toxicity, air/moisture sensitivity, and being commercially unavailable. Herein, we show a simple, mild, and efficient aerobic oxidation procedure of amines using inorganic ligand-supported non-precious metal catalysts 1, (NH4) n[MMo6O18(OH)6] (M=Cu2+; Fe3+; Co3+; Ni2+; Zn2+, n=3 or 4), synthesized by a simple one-step method in water at 100 °C, demonstrating that the catalytic activity and selectivity can be significantly improved by changing the central metal atom. In the presence of these catalysts, the catalytic oxidation of primary and secondary amines, as well as the coupling of alcohols and amines, can smoothly proceed to afford various imines with O2 (1 atm) as the sole oxidant. In particular, the catalysts 1 have transition-metal ion core, and the planar arrangement of the six MoVI centers at their highest oxidation states around the central heterometal can greatly enhance the Lewis acidity of catalytically active sites, and also enable the electrons in the center to delocalize onto the six edge-sharing MO6 units, in the same way as ligands in traditional organometallic complexes. The versatility of this methodology maybe opens a path to catalytic oxidation through inorganic ligand-coordinated metal catalysis. [ABSTRACT FROM AUTHOR]

A series of aliphatic organoimido derivatives of hexamolybdate based on amantadine, namely (nBu4N)2-[Mo6O18(≡NC10H15)] (1), (nBu4N)2 {cis-[Mo6O17(≡NC10H15)2]} (2), (nBu4N)2{trans-[Mo6O17(≡NC10H15)2]} (3), and (nBu4N)2[Mo6O16- (≡NC10H15)3] (4), was synthesized in reasonable yield by dehydration with N,N'-dicyclohexylcarbodiimide (DCC). They were characterized by IR and UV/Vis spectroscopy, elemental analysis, ESI mass spectrometry, and single-crystal X-ray structure analysis. The spectral and structural similarities and differences between monosubstituted, cis-disubstituted, and transdisubstituted organoimido derivatives were elucidated and may provide guidance for related work on organoimido-functionalized Lindqvist-type polyoxometalates. In addition, trans-disubstituted and polysubstituted derivatives containing aliphatic organoimido ligands have not yet been reported, and the crystal structure of the trans isomer may lead us to a deeper understanding of disubstituted derivatives. Furthermore, proliferation and morphology of MCF-7 cells were studied with compound 1. The present results show that the DCC-dehydrating protocol could be an efficient approach to covalently graft bioactive ligands such as amantadine onto POMs and enhance their application in clinical cancer treatment. [ABSTRACT FROM AUTHOR]

Trifluoromethylation of tetraphenlyborate counterions was successfully used to improve the electrochemical stabilities and device performance of cationic iridium(III) complexes. Melioration of the thermal, photoluminescent, electrochemical, and electrophosphorescent characteristics was achieved. Interionic hydrogen bonds were first found between the aromatic hydrogen atoms in the ancillary ligands of cations and the fluorine atoms in the trifluoromethyl groups of the anions. The strong impact of the counterions on the charge transport in the devices was investigated. A compound with two trifluoromethyl groups in the tetraphenlyborate ion shows the highest photoluminescent efficiency, the best electrochemical stability, and the greatest performance in green-blue-emitting devices, with a high current efficiency of 12.4 cd A−1 and an emission peak at λ=480 nm. The efficiencies achieved are the highest reported for OLEDs with ionic complexes emitting in the blue-green region. [ABSTRACT FROM AUTHOR]

An inorganic-organic hybrid surfactant with a hexavanadate cluster as the polar head group was designed and observed to assemble into micelle structures, which further spontaneously coagulate into a 1D anisotropic structure in aqueous solutions. Such a hierarchical self-assembly process is driven by the cooperation of varied noncovalent interactions, including hydrophobic, electrostatic, and hydrogen-bonding interactions. The hydrophobic interaction drives the quick formation of the micelle structure; electrostatic interactions involving counterions leads to the further coagulation of the micelles into larger assemblies. This process is similar to the crystallization process, but the specific counterions and the directional hydrogen bonding lead to the 1D growth of the final assemblies. Since most of the hexavanadates are exposed to the surface, the 1D assembly with nanoscale thickness is a highly efficient heterogeneous catalyst for the oxidation of organic sulfides with appreciable recyclability. [ABSTRACT FROM AUTHOR]

Doubly modified: Polyoxometalates can incorporate a large number of differENt functionalities in a way that mixes the ligands in a one ‐ pot reaction. A class of mixed organoimido bifunctionalized hexamolybdates is presENted that involves two differENt moieties L1 and L2, namely, differing aromatic, aromatic and aliphatic, and aliphatic moieties. [ABSTRACT FROM AUTHOR]

The functionalization of polyoxometalates (POMs), especially with an amino group to yield organonitrogenous derivatives of POMs, is an efficient approach to the enrichment of their structures and the diversification of their properties for various applications. The mechanism for the formation of organonitrogenous-derivatized hexamolybdates was explored by investigating the monofunctionalization of the [Mo6O19]2− ion with methylamine using the density functional theory (DFT) method. The calculations show that the direct imidoylization of hexamolybdate with methylamine is both kinetically and thermodynamically unfavorable. However, this imidoylization was found to take place readily in the presence of dimethylcarbodiimide (DMC), for which the free-energy barrier was calculated to be +32.5 kcal mol−1 in acetonitrile. Moreover, various factors controlling the efficiency of the imidoylization were examined. The calculations show that [W5MoO19]2− has a relatively lower reactivity than [Mo6O19]2−, and that the imidoylization of [W6O19]2− is an unfavorable process. With respect to the effect of carbodiimides, it is found that the catalytic activity is directly proportional to the electron-withdrawing effects of the substituents. As to the reactivity of RNH2, the computation results indicate that the free-energy barriers of the substitution reactions are linearly correlated with the basicity constants (p Kb) of the amino groups. It is noteworthy that the introduction of the proton dramatically decreases the free-energy barrier of the imidoylization of [Mo6O19]2− catalyzed by DMC to 24.3 kcal mol−1 in acetonitrile. [ABSTRACT FROM AUTHOR]

An inorganic–organic hybrid surfactant with a hexavanadate cluster as the polar head group underwent stepwise assembly into micelles and finally, a 1D nanobelt structure with the cooperation of hydrophobic, electrostatic, and hydrogen‐bonding interactions; these last interactions are directional and lead to the anisotropic assemblies. The nanobelts are highly efficient heterogeneous catalysts for the oxidation of organic sulfides because most of the hexavanadates are exposed to the surface, showing its potential application in the petroleum industry and in environmentally benign chemistry. For more details see the Full Paper by T. Li, Y. Wei, T. Liu et al. on page 9589 ff. [ABSTRACT FROM AUTHOR]