Porous supramolecular templating

Since the discovery of the M41S materials with regular mesopore structure by Mobils scientists [1], many researchers have reported on the synthetic method, characterization, and formation mechanism. Especially, the new concept of supramolecular templating of molecular aggregates of surfactants, proposed as a key step in the formation mechanism of these materials, has expanded the possibility of the formation of various mesoporous structures and gives us new synthetic tools to engineer porous materials [2],... 

As described above, molecular and supramolecular templating methods have been very successfully applied for the syntheses of a large variety of microporous systems (e.g., zeolites, AlPOs) and mesoporous systems, respectively. Such approaches allow the design of the pore structure inside a crystal or particle. The simultaneous control about the pore structure at the micro and the macro scale during the formation process can be realized by the combination of at least two strategies. The combination of molecular templating with a sol-gel processing approach results in porous spheres [204]. 

Multimodal porous systems in the form of monolithic-shaped forms (bodies) were obtained from a process where a (true) liquid-crystal templating is combined with a sol-gel process [205]. One characteristic of such a process is the incompatibility of lyotropic surfactants with an alcohol, mostly an inherently produced alcohol, which is responsible for the phase separation during the sol-gel processing, stabilizing the resulting monolithic architecture of the monolith [206]. Different approaches use various components, namely, the alcohol source, the silicate sources (both are sometimes combined in one molecule), and molecular or supramolecular templating agents [207]. 

Compound 12 does not generate a CP, nevertheless it packs, forming a porous supramolecular network sustained only by noncovalent interactions. The excess of bpy employed in the synthesis very likely plays a templating role in the crystal... 

Many of the materials currently under development draw their inspiration from structures found in nature. That is, by mimicking the supramolecular architecture of natural materials, one can prepare complex materials capable of highly sophisticated functions. An important aspect of this work involves the selection of microorganism templates (e.g., diatomite) based on specific porous structures that may benefit targeted applications. 

The methods of soft chemistry include sol-gel, electrochemical, hydrothermal, intercalation and ion-exchange processes. Many of these methods are employed routinely for the synthesis of ceramic materials. - There have been recent reviews of the electrochemical methods, intercalation reactions, and the sol-gel technique. The sol-gel method has been particularly effective with wide-ranging applications in ceramics, catalysts, porous solids and composites and has given rise to fine precursor chemistry. Hydrothennal synthesis has been employed for the synthesis of oxidic materials under mild conditions and most of the porous solids and open-framework structures using organic templates are prepared hydro-thermally. The advent of supramolecular chemistry has started to make an impact on synthesis, mesoporous solids being well known examples. ... 

Hydrogen bonds (H-bonds) are ideal noncovalent interactions to construct supramolecular nanoporous architectures since they are highly selective and directional [16]. H-bonds are formed when a donor with an available acidic hydrogen atom interacts with an acceptor that carries available nonbonding electron lone pairs. The strength of the H-bond depends mainly on the solvent and number and sequence of the H-bond donors and acceptors. Various supramolecular polymer materials have been developed which use H-bonds as structural element to position molecules. After removal of these molecular templates, a porous material is obtained to fabricate molecule specific systems. 

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