Bonded- and discreted-Lindqvist hexatungstate-based copper hybrids as heterogeneous catalysts for the one-pot synthesis of 2-phenylquinoxalines via 2-haloanilines with vinyl azides or 3-phenyl-2H-azirines

One bonded- and one discreted-Lindqvist hexatungstate-based copper hybrids (Cu-POMs) ([Cu2(O)OH(phen)2]2[W6O19]·6H2O (1) and [Cu2(phen)4Cl] [HW6O19]·2H2O (2) (phen = 1,10-phenanthroline)) were controllably synthesized and routinely characterized. Cu-POMs 1-2 consisted of identical [W6O19] unit and similar copper-phen complexes, the two units are bonded via four Cu-O chemical bonds in compound 1; however, compound 2 is discreted and stabilized by intermolecular electrostatic interactions. Importantly, these Cu-POMs catalysts were first applied in the novel reaction for the preparation of 2-phenylquinoxalines via the one-pot coupling and oxidation reactions of 2-haloanilines with vinyl azides or 3-phenyl-2H-azirines under mild conditions, and Cu-POMs 1 showed higher catalytic performance in good yields (79-84%). The reactions exhibit some functional group tolerance and allow for the preparation of a number of 2-phenylquinoxalines.

Two novel bi-functional hybrid materials constructed from POMs and a Schiff base with excellent third-order NLO and catalytic properties

The first polyoxometalates modified by a porphyrin-resembling planar Schiff base have been successfully designed and synthesized under hydrothermal conditions. The third-order NLO responses indicated that they are excellent third-order NLO materials. Their catalytic performances are also investigated.

Crystal structures and spectral properties of two polyoxometalate-based inorganic-organic compounds from silver-azine building blocks with bis-bidentate and tridentate ligands

Two polyoxometalate-based inorganic-organic hybrid compounds constructed from silver(I)-L species and saturated Keggin type polyoxoanion, [Ag2L2(1)]2(SiMo12O40)·1.5DMF·0.5CH3OH⋅H2O 1 and [{Ag4L2(2)(DMF)5}(SiMo12O40)] 2 (L(1) = phenyl 2-pyridyl ketone azine, L(2) = 3-phenyltriazolo[1,5-a]pyridine), have been synthesized and structurally characterized by IR, UV, elemental analysis, XRPD and complete single crystal structure analyses, where the ligands L(1) and L(2) are bis-bidentate and tridentate azines synthesized with the same materials under different conditions. The structure of 1 exhibits a dinuclear double-helicate with [SiMo12O40](4)(-) anions as counter ions, where all of the Ag centers coordinate to bis-bidentate chelating ligands. Compound 2 displays a two-dimensional sheet formed by the Ag-organic infinite chains and the [SiMo12O40](4)(-) alternately arranged in a "rail-like" fashion. The luminescent properties of 1 and 2 in the solid state were investigated.

Spontaneous resolution through helical association of a Cu-azamacrocyclic complex with Lindqvist-type isopolyanion

Anionic metathesis reaction between the perchlorate salt of a copper-tetraazamacrocycle complex and the tetrabutylammonium salt of Lindqvist-type isopolyoxometalates in acetonitrile leads to the formation of two new inorganic-organic hybrid solids formulated as [Cu(L)(MeCN)][W(6)O(19)] (1) and [Cu(L)(MeCN)][Mo(6)O(19)] (2). Interestingly, both ion-pair complexes crystallize in a chiral space group P2(1)2(1)2(1). Crystallographic analysis of the obtained compounds reveals the occurrence of spontaneous resolution during crystallization. Both the enantiomorphs of compound 1 have been structurally characterized, whereas the resolution of compound 2 is rather poor.

Tris(4,4'-di-tert-butyl-2,2'-bipyridine-κN,N')molybdenum(II) μ(6)-oxido-dodeca-μ(2)-oxido-hexa-oxidohexa-molybdate(VI) acetonitrile tetra-solvate

The asymmetric unit of the title compound, [Mo(C(18)H(24)N(2))(3)][Mo(6)O(19)]·4CH(3)CN, comprises an [Mo(di-t-Bu-bipy)(3)](2+) cation (di-t-Bu-bipy is 4,4'-di-tert-butyl-2,2'-bipyridine), two halves of Lindqvist-type [Mo(6)O(19)](2-) anions (with each anion completed by the application of a center of inversion) and four acetonitrile solvent mol-ecules. The geometry around the metal atom of the cation resembles a distorted octa-hedron, with each of the three di-t-Bu-bipy ligands being almost planar [deviation from planarity < 6.3 (2)°]. Supra-molecular inter-actions, namely Mo=O⋯π, C N⋯π, C-H⋯O and C-H⋯N, along with electrostatic forces, mediate the crystal packing. Two of the tert-butyl groups are affected by rotational disorder which was modeled over two distinct positions with major site occupancies of 0.707 (9) and 0.769 (8).