A facile precursor route to transition metal molybdates using a polyzwitterionic matrix bearing simultaneously charged moieties and complexing groups

Abstract

An unconventional but easily accessible precursor route involving the thermal treatment of hybrid precursors containing an ampholytic polymer matrix is developed to prepare multimetallic oxides of catalytic interest such as transition metal molybdates. A copolymer of diallyldimethylammonium chloride and a functionalized maleamic acid bearing an amine group suited for cation complexation was designed, synthesized and used as a matrix to stabilize inorganic species generated in solution from Ni(NO3)(2)center dot 6H(2)O, Co(NO3)(2)center dot 6H(2)O and/or Mn(NO3)(2)center dot 4H(2)O together with (NH4)(6)Mo(7)O(24)center dot 4H(2)O. UV-vis-NIR as well as C-13-NMR studies suggest that the interactions between the cations and the polymer in solution are mainly electrostatic. Only minor complexation interactions take place under certain conditions. Homogeneous hybrid blends were prepared from these solutions. The presence of a complexing amine group in addition to the charged betaine moieties in the polymer permits stabilization of more than stoichiometric amounts of the metal species in the blends. XRD measurements suggest that the homogeneity in the solid state can be kept up to about 1.5 mol of each metal that is incorporated ( anionic as well as cationic) per mol of repeat units of the copolymer. The blends were calcined under air at 600 degrees C to produce the simple as well as mixed nickel, cobalt and manganese molybdates. Characterization of the final phases by XRD and Raman spectroscopy indicates that the alpha- as well as the beta-molybdate phases can be prepared, and that the mixed structures are solid solutions of the simple NiMoO4, MnMoO4 and CoMoO4. If the precursors engaged are homogeneous, the pH of the precursor solution, the amount of metal that is incorporated in the matrix, and the nature of the polymer matrix seem to exert only a minor influence on the nature of the final phase, which demonstrates the versatility and facile applicability of the method

Effect of a new hydrophobically modified polyampholyte on the formation of inverse microemulsions and the preparation of gold nanoparticles

“…The alternating character of copolymers made from diallylammonium and maleamate ion pairs has been shown before [39]. The molar masses of such copolymers are typically moderate in the order of 20,000 g/mol [45].…”

“…In the context described above, this work aimed at the synthesis of a new polyampholyte with a medium long hydrophobic side chain, which is sufficient for self-organizing the polymer like classical polysoap [3,4,12,39], and its incorporation into inverse microemulsions droplets, which can be used as a template for the synthesis of inorganic particles with colloidal dimensions. For this purpose, a new alternating copolymer of the cationic monomer (N,N-diallyl-N,N-dimethylammonium chloride) and the weak anionic monomer octylmaleamic acid is synthesized, and incorporated in a SDS-based microemulsion.…”

NiMoO4 preparation from polyampholytic hybrid precursors: Benefiting of the memory effect in the oxidative dehydrogenation of propane

“…that are responsible for good performance. In continuation with some previous work, the possibility envisaged here is the formation of mixed oxides (Ni Mo O) through the thermal degradation of hybrid precursors made from the association of an organic copolymer matrix and inorganic ions [10,11].…”

Solid‐State Reactions

“…Recently, investigations were undertaken for using more elaborate polymer structures: these consisted of polyampholytes resulting from the association of monomers bearing carboxylic acid and amine moieties. This approach has been validated to obtain several transition metal molybdates, starting from inorganic precursors and a copolymer matrix made from diallylammonium and (functionalized) maleic or maleamic acid units [125,126]. Depending on the substituents present on the main chain, these polymers offer the advantage of tunable properties such as the solubility in various polar media, the number and nature of functional groups of each type, the presence of selected substituents able to induce controlled steric hindrance, cation complexation, or superstructures in the solid state.…”