Hipassia M. Moura

Hydrothermal synthesis (HTS) designates the use of hot liquid water as medium for chemical reactions. The technique is very well established for generating crystalline inorganic materials. Recently it was shown that HTS can also be used to prepare organic compounds, which are all bearing a high content in aromatics and heterocyclics. The technique is environmentally friendly for using solely water as medium, especially in comparison to conventional syntheses of such compounds. Here we present HTS of organic compounds in a fashion that allows for implementing it in the classroom. First, we show how HTS can be used as an example to introduce the timely concepts of green chemistry and sustainable syntheses. Second, we review organic cyclocondensation reactions including reaction equilibrium and enthalpic/entropic driving forces as well as real-life examples of cyclocondensation products, as HTS is especially amenable to cyclocondensations. Third, as liquid high-temperature water is well suited to review the temperature-dependence of certain physicochemical features, we provide interactive plots for exploring these data. Fourth, we develop a classroom friendly HTS of a simple organic colorant, that can be performed simple in kitchen pressure cookers. Fifth, at the hand of this classroom experiment we show how measures for the green-ness of a chemical synthesis, such as the Ecoscale are used.

Hydrothermal synthesis (HTS) designates the use of hot liquid water as medium for chemical reactions. The technique is very well established for generating crystalline inorganic materials. Recently it was shown that HTS can also be used to prepare organic compounds, which are all bearing a high content in aromatics and heterocyclics. The technique is environmentally friendly for using solely water as medium, especially in comparison to conventional syntheses of such compounds. Here we present HTS of organic compounds in a fashion that allows for implementing it in the classroom. First, we show how HTS can be used as an example to introduce the timely concepts of green chemistry and sustainable syntheses. Second, we review organic cyclocondensation reactions including reaction equilibrium and enthalpic/entropic driving forces as well as real-life examples of cyclocondensation products, as HTS is especially amenable to cyclocondensations. Third, as liquid high-temperature water is well suited to review the temperature-dependence of certain physicochemical features, we provide interactive plots for exploring these data. Fourth, we develop a classroom friendly HTS of a simple organic colorant, that can be performed simple in kitchen pressure cookers. Fifth, at the hand of this classroom experiment we show how measures for the green-ness of a chemical synthesis, such as the Ecoscale are used.

Energy storage will be a primordial actor of the ecological transition initiated in the energy and transport sectors. As such, innovative approaches to design high-performance electrode materials are crucial for the development of the next generation of batteries. Herein, a novel dual redox-active and porous polyimide network (MTA-MPT), based on mellitic trianhydride (MTA) and 3,7-diamino-N-methylphenothiazine (MPT) monomers, is proposed for applications in both high energy density lithium batteries and symmetric all-organic batteries. The MTA-MPT porous polyimide was synthesized using a novel environmentally-friendly hydrothermal polymerization method. Rooted in its dual redox proprieties, the MTA-MPT porous polyimide exhibits a high theoretical capacity making it a very attractive cathode material for high energy density battery applications. The cycling performance of this novel electrode material was assessed in both high energy density lithium batteries and light-weight symmetric all-organic batteries, displaying excellent rate capability and long-term cycling stability.

PBI dyes@SiO₂ hybrid materials are generated by hydrothermal synthesis. They exhibit solution-like fluorescence and photocatalytic activity. An in-depth materials formation study reveals a network of PBI-linked POSS-type cages.

We report on the hydrothermal polymerization (HTP) of porous polyimide (PI) networks using the medium H₂O and the comonomers 1,3,5-tris(4-aminophenyl)benzene (TAPB) and pyromellitic acid (PMA).

Biogenic metal oxides (M_xO_y) feature structures as highly functional and unique as the organisms generating them. They have caught the attention of scientists for the development of novel materials by biomimicry. In order to understand how biogenic M_xO_y could inspire novel technologies, we have reviewed examples of all biogenic M_xO_y, as well as the current state of understanding of the interactions between the inorganic M_xO_y and the biological matter they originate from and are connected to. In this review, we first summarize the origins of the precursors that living nature converts into M_xO_y. From the point-of-view of our materials chemists, we present an overview of the biogenesis of silica, iron and manganese oxides, as the only reported biogenic M_xO_y to date. These M_xO_y are found across all five kingdoms (bacteria, protoctista, fungi, plants and animals). We discuss the key molecules involved in the biosynthesis of M_xO_y, the functionality of the M_xO_y structures, and the techniques by which the biogenic M_xO_y can be studied. We close by outlining the biomimetic approaches inspired by biogenic M_xO_y materials and their challenges, and we point at promising directions for future organic-inorganic materials and their synthesis.

Multiple synthetic strategies were performed in order to tether a zirconium-based catalyst to the 2D and 3D molecular sieves for olefin polymerizations. The anchoring of fluorene silane to the mesoporous MCM-41 was performed in order to obtain a stable catalyst for olefin polymerization (1@MCM-41). Using spectroscopic methods, this system was shown to have the metal center locked on a face down conformation with the surface. Also, immobilized zirconium complexes have been prepared on three different types of aminopropyl-modified supports (2@magadiite, 2@MCM-41 and 3@MCM-48). The advantage of this latter method of immobilization would be the reduction of the steric effect caused by the support: the catalyst, distant from the surface, is more exposed to the monomer and this situation may lead to an increase in the catalytic activity compared to 1@MCM-41. However, a medium size chain as a spacer between the support and the metallocene is still flexible enough to bend and predisposes the metal center to interact with the support surface; this effect is more evident when the nature of the support is of fixed pore dimensions. These supported catalysts exhibited activity for ethylene polymerization, resulting in linear PEs with high melting temperatures. In order to retain a metallocene assembled as in a homogeneous environment, a multi-step reaction was investigated (4@magadiite) but it led to the leaching of the organic moieties from the surface during catalyst preparation. The best catalytic performance was achieved when homogeneous Oct-amido catalyst (5) was reacted with the surface of magadiite and n-alkyl-AlPO-kan.

Novel hybrid mesoporous and functionalized materials with controllable surface area and pore dimensions with functional basic sites (–NH₂) were synthesized from magadiite and [Al]-magadiite as layered silicate precursors. The variable pore structure and properties of these materials were investigated in these solids by using different CTA⁺/Na⁺ (CTA⁺ = cetyltrimethylammonium cation) molar ratios in the pre-modification step with aminopropyltriethoxysilane (APTS) and tetraethoxysilane (TEOS). Characterizations were carried out by different techniques to probe the effects of the amounts of interlayer surfactant in the synthesis of the pillared and/or grafted materials. The crystalline structures of magadiite and [Al]-magadiite layers were maintained as evidenced by FT-IR and SAED and contain pillars and aminopropyl groups in the interlayer space. The hybrid solids were compared to the pillared forms (H. M. Moura, F. A. Bonk and H. O. Pastore, Eur. J. Mineral., 2012, 24, 903) and to the aminopropyl-grafted forms and presented the properties of both solids with the CO₂ adsorption capability improved considerably.