Molcano: Molecular Language for Chemical Assembly Notation
摘要
Molecular design operates through fragment-based reasoning, yet many widely used molecular encodings rely on atom-level representations. This misalignment makes fragment-by-fragment construction and scaffold-centered designs hard to realize, especially for fused-ring systems. We present MOLCANO, a molecular language that represents molecules as chemically interpretable fragments linked by explicit junction tags, supporting single-bond, face-to-face, and even substructure-level connections for versatile scaffold assembly. It facilitates the construction of chemically complex structures while maintaining interpretability throughout the generation process. We validate MOLCANO across three open datasets spanning small-molecule drugs and organic electronic materials, covering de novo generation, superstructure growth/decoration, and medicinal-chemistry scaffolding. This also integrates with reinforcement learning for goal-oriented optimization of properties and with large language models for interactive, text-guided editing. By aligning computational representations with chemists’ modular reasoning, MOLCANO broadens the accessible chemical design space and accelerates molecular innovation in drug discovery, materials science, and beyond.