A team from the Instituto de Ciencia Molecular (ICMol) at the Universitat de València has developed a new synthetic strategy to design porous materials capable of modifying their structure in a controlled manner in response to environmental molecules. The development originates from the ERC LIVINGPORE project, led by Carlos Martí-Gastaldo, head of the group and professor in the Department of Inorganic Chemistry at the UV, and proposes a modular platform based on synthetic amino acids that combines chemical stability with adaptive capacity, two properties that are difficult to integrate in this type of material.

The study, recently published in the journal Chem, introduces a new family of crystalline structures called MUV-X (Materials of Universitat de València), where X identifies the amino acid used. These materials are built from modified peptides and zinc metal centers. These architectures belong to the class of metal-organic frameworks (MOFs), porous solids with internal cavities capable of hosting small molecules.

Biological inspiration for dynamic materials

Some MOFs exhibit structural flexibility, allowing them to modify the size or shape of their pores in response to interacting molecules. However, integrating this dynamic behavior without compromising the chemical stability of the material has been one of the main challenges in the development of this type of porous architecture.

The ICMol-UV team addressed this issue by drawing inspiration from how proteins function, where rigid regions coexist with flexible segments that enable reversible conformational changes without loss of structural integrity.

“Proteins are capable of adapting to their environment while maintaining their structural integrity. Our goal was to transfer that balance between rigidity and flexibility to the design of synthetic materials,” explains Carlos Martí-Gastaldo, head of the FUNIMAT team.

Following this idea, the researchers designed molecular linkers based on amino acids modified with chemical units called pyrazoles. These allow the construction of rigid metal chains that act as structural elements, while the peptide backbone introduces controlled mobility.

According to the authors, this combination enables the integration of robustness and adaptability within the same material.

Three-dimensional architectures and layered materials

The study demonstrates that the nature of the amino acid used determines the final architecture of the material. Using alanine, the researchers obtained a three-dimensional network (MUV-A), whereas amino acids with bulkier side chains, such as phenylalanine or tyrosine, lead to stacked two-dimensional structures (MUV-F and MUV-Y).

This structural change occurs due to steric interactions between side chains, which determine how the molecular building blocks assemble during crystallization.

In addition to controlling the material’s shape, the type of amino acid also modulates its behavior in the presence of external molecules.

“The identity of the amino acid not only defines the final structure but also how the material responds to external molecules,” notes Natalia M. Padial, co-author of the study.

Selective response to solvents

Experiments show that some of these materials can reorganize their structure when interacting with certain solvents, modifying the size and shape of their pores.

In particular, the three-dimensional material MUV-A exhibits high structural flexibility, capable of expanding or contracting depending on the guest hosted within its pores. In contrast, the layered versions show more selective responses, governed by specific interactions such as hydrogen bonding or aromatic contacts.

The combination of structural experiments and computational simulations made it possible to identify the mechanisms governing these transformations, based on interactions between the guest molecules and the peptide backbone of the material.

High chemical and thermal stability

One of the most notable aspects of this work is the achieved stability. Unlike most peptide-based materials, which tend to degrade easily in water or lose their structure after solvent removal, these new networks retain their crystallinity and porosity even under acidic, basic, or moderately hydrothermal conditions.

The authors attribute this resistance to the presence of rigid metal pyrazolate units, known for generating particularly robust structures within reticular chemistry.

Towards programmable porous materials

According to the study, this strategy opens new possibilities for designing porous materials in which structural response can be programmed through the choice of amino acid.

“This strategy allows us to design materials that are simultaneously flexible and robust, in which we can precisely define the chemical environment of the pore through the selection of the amino acid. It is an important step towards porous platforms whose structural response can be rationally programmed depending on the molecule we aim to recognize,” says Víctor Carratalá, co-author of the study.

The researchers suggest that these materials could have future applications in molecular recognition, selective enantiomer separation, or the chemical activation of chiral molecules, thanks to the combination of stability and adaptability.

Referencia: Carratalá, V. et al. Synthetic Amino Acids for Programming Adaptive Response in Pyrazolate Peptide Frameworks. Chem (2026). https://doi.org/10.1016/j.chempr.2026.102992