A New Class of Organic−Inorganic Hybrid Materials: Hydrothermal Synthesis and Structural Characterization of Bimetallic Organophosphonate Oxide Phases of the Mo/Cu/O/RPO32- Family

Hybrid Cu-Containing Compounds Based on Lacunary Strandberg Anions: Synthesis under Mild Conditions, Crystal Structure, and Magnetic Properties

A one-pot reaction of a copper source (metallic powder Cu⁰ or Cu²⁺ salts) and bpy (bpy = 2,2'-bipyridine) in the presence of (NH₄)₂HPO₄ and (NH₄)₆Mo₇O₂₄·4H₂O yields heterometallic hybrid compounds of the general type {[Cu(bpy)_n(H₂O)_m]_p[P₂Mo_xO_y]}. The structures exhibit a number of phosphomolybdate POMs including not only a common Strandberg anion [P₂Mo₅O₂₃]^6- but also its unprecedented bi- and trilacunary derivatives [P₂Mo₃O₁₈]^8- and [P₂Mo₂O₁₅]^8-. The structural determinants including the metal source (copper powder vs copper salts), counterion of the salts, and stoichiometry of the reagents were examined. An ex situ EPR study revealed the formation of different Cu^II complexes in the reaction mixture depending on the copper precursor. The obtained compounds have been found to possess selectivity toward the sorption of methylene blue in a mixture of organic dyes. DC magnetic measurements of 1-3 indicate rather strong antiferromagnetic metal-metal exchange interactions. Compound 1 exhibits field-induced slow magnetic relaxation in AC magnetic measurements, which is a rarely observed phenomenon among Cu(II) complexes.

From Simplicity to Complexity in Grafting Dawson-Type Polyoxometalates on Porphyrin, Leading to the Formation of New Organic-Inorganic Hybrids for the Investigation of Third-Order Optical Nonlinearities

Four new organic-inorganic hybrids, [N(C₄H₉)₄]₅H[{HNC₂O(CH₂O)₃P₂V₃W₁₅O₅₉}C₄₄N₄H₂₉O₃] (TPPOH-1POM), [N(C₄H₉)₄]₁₀H₂[{HNC₂O(CH₂O)₃P₂V₃W₁₅O₅₉}₂C₄₄N₄H₂₈O₂] (TPPOH-2POM trans), [N(C₄H₉)₄]₁₀H₂[{HNC₂O(CH₂O)₃P₂V₃W₁₅O₅₉}₂C₄₄N₄H₂₈O₂] (TPPOH-2POM cis), and [N(C₄H₉)₄]₁₅H₃[{HNC₂O(CH₂O)₃P₂W₁₅V₃O₅₉}₃C₄₄N₄H₂₇O] (TPPOH-3POM), have been synthesized by covalently grafting the Dawson-type polyoxometalate (POM) [N(C₄H₉)₄]₅[H₄P₂W₁₅V₃O₆₂] onto new porphyrins N-[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]-4-[10,15,20-tris(4-hydroxyphenyl)porphyrin-5-yl]benzamide (TPPOH-1Tris), 4,4'-[5,15-bis(4-hydroxyphenyl)porphyrin-10,20-diyl]bis[ N-[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]benzamide] (TPPOH-2Tris trans), 4,4'-[10,15-bis(4-hydroxyphenyl)porphyrin-5,20-diyl]bis[ N-[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]benzamide] (TPPOH-2Tris cis). and 4,4',4″-[20-(4-hydroxyphenyl)porphyrin-5,10,15-triyl]tris[ N-[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]benzamide] (TPPOH-3Tris), respectively, in N, N-dimethylacetamide under nitrogen. The hybrid compounds were thoroughly characterized by elemental analysis, FT-IR, NMR (¹H, 2D NOESY, ³¹P, and ⁵¹V), ESI-MS, MALDI-TOF-MS, UV-vis, and fluorescence spectroscopy. All porphyrins and their corresponding hybrids exhibited remarkable third-order nonlinear-optical responses under laser irradiation, with the intensity of light at focus E₀ being 4.2 μJ at wavelength 532 nm, pulse duration τ = 6 ns, and repetition rate 10 Hz. The molecular second hyperpolarizability (γ) values of the hybrids (TPPOH-1POM, TPPOH-2POM trans, TPPOH-2POM cis, TPPOH-3POM) were calculated to be 8.48 × 10^-28 esu, 8.94 × 10^-28 esu, 10.16 × 10^-28 esu, and 8.93 × 10^-28 esu, while the molecular second hyperpolarizability (γ) of their corresponding porphyrin precursors (TPPOH-1Tris, TPPOH-2Tris trans, TPPOH-2Tris cis, and TPPOH-3Tris) were 7.19 × 10^-28 esu, 8.09 × 10^-28 esu, 9.07 × 10^-28 esu, and 7.24 × 10^-28 esu, respectively. The γ values of the cis forms were found to be superior to those of all other compounds, indicating the significant role of the greater dipole moment and low symmetry of the cis form compared to other compounds. It was also found that the fluorescence intensity was decreased by 81.52%, 90.37%, 93.93%, and 84.62% for the hybrids TPPOH-1POM, TPPOH-2POM trans, TPPOH-2POM cis, and TPPOH-3POM with respect to their corresponding precursors, respectively, which reveals the Dawson-type POM as a strong quencher. This quenching phenomenon not only indicates again unequivocally the formation of hybrid compounds but also may imply a photoinduced electron/energy-transfer process favored from a porphyrin moiety to a Dawson-type POM moiety.

Syntheses and characterization of phosphonates and diphosphonates of molybdenum, A4[(MoO3)5(O3PR)2]·xH2O, A2[Mo2O5(O3PR)2] and A2[Mo2O5(O3P-R-PO3)] (A = K, Rb, Cs, Tl, NH4)

Cs₄[(MoO₃)₅(O₃PPh)₂]·6H₂O and K_1.5(H₃O)_0.5[Mo₂O₅(O₃PPh)₂] are molecular and non-molecular phenylphosphonates of molybdenum that contain discrete [(MoO₃)₅(O₃PPh)₂]⁴⁻ and layered [Mo₂O₅(O₃PPh)₂]²⁻ anions respectively.

Controllable assembly, characterization and catalytic properties of a new Strandberg-type organophosphotungstate

A new Strandberg-type organophosphotungstate was assembled under hydrothermal conditions and displayed good fluorescence properties and catalytic activity.

Sonochemical synthesis of two new copper(II) complexes with azo ligands derived from anthranilic acid and β-naphtol

Nanostructures of two new copper(II) complexes, (CuL1), 0.5EtOH. 1.5H2O (1), [H2L1=5-(4-Carboxy phenyl azo) anthranilic acid], (Cu(L2)2) (2), [HL2=1-(4-Carboxy phenyl azo) 2-naphtol] have been synthesized by the reaction of H2L1 and HL2 with Cu(OAc)2 · H2O through sonochemical process. Calcination of the nano-sized compounds 1-2 yield CuO nanoparticles at 550-450°C under air atmosphere. Metallic copper nanoparticles were prepared by direct calcination of compound 2 in surfactant at 180°C. These nanostructures were characterized by X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM). Thermal stability of compounds 1-2 was studied by thermal gravimetric (TG) and differential thermal analyses (DTA).

Controlled assembly of hybrid architectures based on carboxylic acid ligands and [(O3PCH2PO3)Mo6O22]12−

Polyanion 2a with a reverse symmetrical “crown-type” structure is composed of two {(HO₃PCH₂PO₃)Mo₆O₁₈(CH₃CO₂)₂} subunits and a linking bridge.

Construction of organic-inorganic hybrid molybdophosphonate clusters with copper-bipyridine

An organic-inorganic hybrid polyoxomolybdate with formula as [Cu(2,2'-bpy)(H2O)]2[Cu(2,2'-bpy)(H2O)3][(O3PCCH3(OH)PO3)2Mo(VI)4O11(H2O)2]·7H2O (1) (2,2'-bpy=2,2'-bipyridine) has been successfully synthesized constructing by diphosphonate H2O3PC(CH3)(OH)PO3H2 (1-hydroxyethylidene-1,1-bisphosphonic acid, noted as HEDP or etidronate) under conventional aqueous solution. 1 was characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, thermogravimetric (TG) analysis, and X-ray photoelectron spectroscopy (XPS). Each anion cluster of 1 can be regarded as the fusion of two [{Cu(2,2'-bpy)(H2O)}(O3PCCH3(OH)PO3)Mo(VI)2O6](2-) subunits with an additional six-coordinated [Cu(2,2'-bpy)](2+) coordination cation linking on one side and there exist weak π-π interactions among the bipyridine groups. The XPS spectra indicate that the oxidation states of Mo and Cu in 1 are +6 and +2, respectively. Photoluminescence properties of 1 and the free 2,2'-bipyridine ligand have been both analyzed, showing that the presence of ligand-to-metal-charge-transfer (LMCT) transitions and metal-ligand coordination have an important effecting on the photoluminescence.

Porphyrin-POSS molecular hybrids

Porphyrin-POSS hybrid: Porphyrin-POSS molecular hybrid composites (see scheme; POSS = polyhedral oligomeric silsesquioxanes) were synthesized and structurally characterized, allowing the realization of truly homogenous dispersion of basic functional building blocks between organic and inorganic components at the molecular level. These materials allow the optimization of aggregation/association behavior and thus the functional optical properties of the porphyrinato zinc compounds.

Amphiphilic properties of dumbbell-shaped inorganic-organic-inorganic molecular hybrid materials in solution and at an interface

Five novel dumbbell-shaped polyoxometalate (POM)-based inorganic-organic-inorganic molecular hybrids are investigated both in polar solvents and at interfaces for potential amphiphilic properties, which are compared with those of conventional surfactants. These hybrids with the general formula {P(2)V(3)W(15)}(2)-bis(TRIS)-linker are formed by linking two Wells-Dawson-type clusters, [P(2)V(3)W(15)O(62)](9-), with different linear bis(TRIS) linker ligands between the two TRIS moieties. Laser light scattering (LLS) studies reveal the presence of self-assembled vesicular structures in water/acetone mixed solvents, and the vesicle size increases with increasing acetone content, suggesting a charge-regulated process. The elastic constants, which are used to calculate the bending energy during vesicle formation, reveal that the organic ligands play an important role in determining the self-assembly process and that the hybrids do demonstrate amphiphilic behavior at the water/air interface. Furthermore, it is shown that some of the hybrids form monolayers at the interface, with an average molecular area that can be correlated with their organic linkers, as determined from their π-A isotherms. Finally, the hybrids not only display amphiphilic behavior akin to that of a surfactant but also exhibit an unusually high entropy contribution to vesicle formation as a result of their unique large, polar head groups, complex organic linkers, and their special molecular architectures as well as because of the involvement of the amphiphilic tetrabutylammonium (TBA) counterions.

Coordination assemblies of polyoxomolybdate cluster framework: from labile building blocks to stable functional materials

Polyoxomolybdates, an important branch in polyoxometalates chemistry, present complicated solution chemistry and unmatched physicochemical properties, which endows us with both great opportunities and considerable challenges in creating new functional materials. This perspective highlights the recent development on the coordination assembly of transition-metal-substituted heteropolymolybdates by using labile lacunary heteropolymolybdates as inorganic multidentate ligands. A series of strategies have been used to stabilize the lacunary heteropolymolybdate building blocks. Finally, we introduce some researches on the modification of polymolybdates by organic groups in aqueous media, which may shed light on the green chemistry of the functionalization of polyoxomolybdates.

Sonochemical synthesis of nano-scale mixed-ligands lead(II) coordination polymers as precursors for preparation of PbO and PbBr(OH) nano-structures; thermal, structural and X-ray powder diffraction studies

Nano-structures of two new lead(II) two-dimensional coordination polymers, [Pb(2)(2-pyc)(2)(I)(2)](n) (1) and [Pb(2)(2-pyc)(2)(Br)(2)](n) (2), {2-Hpyc=2-pyridinecarboxilic acid } were synthesized by a sonochemical method that produce the coordination polymers at nano-size. The new nano-structures were characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analyses. Compounds 1 and 2 were structurally characterized by single crystal X-ray diffraction and consist of two-dimensional polymeric units. The thermal stability of compounds 1 and 2 were studied by thermal gravimetric and differential thermal analyses. PbO and PbBr(OH) nano-structures were obtained by calcination of the nano-structures of compounds 1 and 2 at 400 degrees C, respectively.