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Three rigid-rod conjugated organic−inorganic hybrid nanodumbbells (Bu4N)4[O18Mo6N(C6H4)NMo6O18] (1), (Bu4N)4[O18Mo6N(C12H8)NMo6O18] (2), and (Bu4N)4[O18Mo6N(C14H12)NMo6O18] (3) bearing terminal polyoxometalate (POM) cages, with different lengths of approximately 2−3 nm and different substituents on the rod, have been synthesized via one-pot reaction of octamolybdate and the appropriate aromatic diamine dihydrochloride with N,N′-dicyclohexylcarbodiimide (DCC) as a dehydrating agent. These complexes have been characterized with UV−vis, IR, 1H NMR, ESI mass spectrometry, cyclic voltammetry, differential pulse voltammetry, and X-ray single-crystal diffraction techniques. The influence of the rod length and substituents on properties of these complexes has been investigated. In addition, the self-assembly of these nanorods has also been explored.

Four novel fluoro-functionalized arylimido-substituted hexamolybadates, (n-Bu4N)2[Mo6O18(NAr)] (Ar = 2-CH3-4-FC6H3 (1), 3-CH3-4-FC6H3 (2), 4-FC6H4 (3), or 2-FC6H4 (4)), in which fluorinated phenylimido group linked to an Mo of hexamolybdate by a Mo−N triple bond, have been prepared via the DCC (N,N′-dicyclohexylcarbodiimide) dehydrating protocol of the reaction of α-octamolybdate ion with 2-methyl-4-fluoroaniline hydrochloride, 3-methyl-4-fluoroaniline hydrochloride, 4-fluoroaniline hydrochloride, or 2-fluoroaniline hydrochloride in anhydrous acetonitrile. All these compounds have been characterized by elemental analysis, UV−vis, IR, 1H NMR, and single-crystal X-ray diffraction analyses. The preliminary biological activity test indicated that these compounds display potent herbicidal activity, in particular against the roots of some tested plants (such as Brassica campestris L., Eclipta prostrata L., Echinochloa crusgallis L., and Cirsium japonicum DC.).

A novel naphthylimido derivative of hexamolybdate, (Bu4N)2[Mo6O18N(Naph-1)] (1), was synthesized for the first time by the reaction of octamolybdate ion and 1-naphthyl amine hydrochloride with DCC (N,N‘-dicyclohexylcarbodiimide) as a dehydrating agent. The ultraviolet−visible absorption spectrum shows the lowest energy electronic transition of 1 occurs at 383 nm, which is dramatically red-shifted compared to that of [Mo6O19]2- and other monosubstituted phenylimido hexamolybdates reported in the literature. Moreover, cyclic voltammetry studies on compound 1 show the reversible reduction wave at −0.53 V, which is cathodically shifted relative to that of [Mo6O19]2-. Another interesting characteristic of 1 is that the cluster anions form supramolecular 1D chains via C−H···O hydrogen bonding interactions.

A novel organic−inorganic hybrid solid, (n-Bu4N)2[Mo6O17(NAr)2] (Ar = o-CH3OC6H4) 1, has been prepared by refluxing of (n-Bu4N)2[Mo6O19] and appropriate o-anisidine in acetonitrile with N-N‘-dicyclohexylcarbodiimide (DCC) as the dehydrating agent. Compound 1 has been characterized by single-crystal X-ray diffraction. Both of the two terminal o-anisidido ligands are linked, respectively, to an Mo atom of the hexamolybdate in a terminal fashion and exhibit an almost linear coordination mode of the Mo⋮N triple bond character. The two o-anisidido aryl rings on the hexamolybdate cluster lie in the cis position, allowing π−π stacking of phenyl ring among the anions. In the crystal, the cluster anions of 1 aggregate into an interesting 1D double chain along the a-axis through π−π stacking and C−H···O hydrogen-bonding interactions. Compared to the hexamolybdate parent, this solid has a smaller optical band gap of 2.25 eV from UV−visible-near-IR reflectance spectroscopy studies. It has also been characterized by 1...