Generation of benzenoid structures using artificial intelligence


Benzenoids are a subfamily of hydrocarbons (molecules composed only of hydrogen and carbon atoms) whose carbon atoms form hexagons. The electronic properties of these molecules, particularly conductivity and magnetism, suggest that they could be used in nanoelectronics, however their synthesis is complex. To solve this problem, a team of researchers from the Institute of Molecular Sciences of Marseille and the Laboratory of Informatics and Systems (CNRS / University of Aix-Marseille) has developed an application that, regardless of the number of cycles, generates all the structures associated with a searched property. Research : ” BenzAI: a program for designing benzenoids with defined properties using constraint programming ” has been published since Journal of Chemical Information and Modeling ».

Benzenoids belong to the family of PAHs (polycyclic aromatic hydrocarbons). PAHs are hydrocarbons whose carbon atoms form rings of different sizes. They are the subject of numerous studies in different fields (organic synthesis, molecular nanoelectronics, interstellar chemistry, etc.) due to their energy stability, their molecular structures or their optical spectra. Their physicochemical properties depend on their size and structure.

Therefore, the electronic properties of benzenoids, molecules formed from hexagonal carbon rings fused into a honeycomb structure, depend on how these hexagons are arranged in the structure. Being able to predict the electronic properties according to the arrangement that the hexagons can assume would allow the chemist to direct his syntheses towards relevant systems.

It is therefore necessary to generate all the possible arrangements of the N hexagons that constitute it and to predict the properties of each of them in order to preserve only the relevant systems in nanoelectronics, and this for each family of benzenoids. If the task is simple when N is small (3 solutions for N = 3), from N = 7, computer processing becomes essential.

BenzAI software

Yannick Carissan and Denis Haguebaum-Reignier of the Marseille Institute of Molecular Sciences, as well as Nicolas Prcovic, Cyril Terrioux and Adrien Varet of LIS, Laboratory of Computer Science and Systems (CNRS / University of Aix-Marseille) are the researchers of the team. They have developed BenzAI, a free and open source calculation software, which allows you to:

  • generate benzenoid structures based on different criteria (number of hexagons / carbon atoms / hydrogen atoms, structural properties, presence or absence of one or more units, etc.),
  • analyze their electronic structure,
  • provide infrared spectra stored in an external database.

BenzAI will thus allow to order the molecules of interest which will have the desired properties once inserted into the devices.

This PPC (Constraint Programming) approach will allow synthesis chemists to focus their efforts on relevant systems such as molecular magnets intended for information storage.

Link to download BenzAI, open and free software:

Sources of the article:

Adrien Varet, Nicolas Prcovic, Cyril Terrioux, Denis Hagebaum-Reignier and Yannick Carissan
BenzAI: A program for designing benzenoids with defined properties using constraint programming
Journal of Chemical Information and Modeling


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