arXiv Machine Learning

On the limitations of molecular representations

The paper evaluates molecular representations used in cheminformatics and small‑molecule machine learning, such as fingerprints and learned embeddings. It finds that current state‑of‑the‑art embedding models do not outperform traditional fingerprints or physicochemical descriptors in capturing graph structure, 3D shape, or ADMET similarity. Additionally, fingerprints exhibit significant limitations, with 225 million to 4 billion molecules in the 10.8 billion‑molecule Enamine REAL database sharing non‑unique representations, which impacts virtual screening.

arXiv AI
4d ago

Benchmarking Pretrained Molecular Embedding Models For Molecular Representation Learning

The study benchmarked 28 pretrained molecular embedding models—including graph neural networks, text transformers, and hybrids—across 25 classification datasets using a controlled framework with hierarchical Bayesian Bradley‑Terry testing. Except for CheMeleon, none of the neural models surpassed the classical ECFP count fingerprint, and external validation with scaffold cross‑validation and Bayesian hierarchical t‑tests found no clear advantage for any embedding method. The authors recommend evaluating both ECFP fingerprints and CheMeleon embeddings in new QSAR/QSPR studies, emphasizing the need for rigorous evaluation standards in molecular representation learning.

By Mateusz Praski, Jakub Adamczyk, Wojciech Czech
arXiv Machine Learning
Sep 1

Structural Hierarchy and Geometry in Molecular Representation Learning

The paper investigates how explicitly supervising molecular embeddings with a molecule’s Bemis‑Murcko scaffold influences representation learning. Experiments compare Euclidean and Lorentz contrastive objectives under two augmentation strengths, showing that scaffold‑supervised models consistently group molecules by identical and related scaffolds. These embeddings also enhance property prediction on several tasks, though the magnitude of improvement varies with the target property and the geometry used.

By David Sulu, Lorenzo Di Fruscia, Jana M. Weber
arXiv AI
Aug 19

Domain-Adapted Molecular Language Models for Efficient Search of Make-on-Demand Libraries

The study evaluates four pretrained molecular language models on six virtual libraries covering drug discovery, organic materials, and catalysis. It finds that native embeddings vary widely in performance, while molecular fingerprints remain consistently strong. Fine‑tuning the models on library‑specific data markedly improves sample efficiency, with several adapted encoders outperforming others across all tasks.

By Henrik Wille, Luis-Finley Sch\"utz, Felix Strieth-Kalthoff
arXiv Machine Learning
Sep 29

WEECFP-SuRGE: A Position-Aware Substructure Encoding Method for Molecular Property Prediction

WEECFP-SuRGE introduces a position‑aware substructure encoding method that combines tokenized hierarchical Morgan fingerprints with graph‑distance‑dependent rotations applied at the input and within transformer self‑attention. The approach captures local chemistry, long‑range interactions, and molecular topology without requiring external pretraining or 3‑D conformer generation. Benchmarks on MoleculeNet and the Therapeutic Data Commons ADMET datasets show competitive performance, and a reconstruction procedure correctly identifies constitutional isomers for 92.6% of a 4,200‑molecule library.

By Robert Epps
arXiv Machine Learning
Jul 8

Multimodal Molecular Representation Learning with Graph Neural Networks, Deep & Cross Networks, and SMILES Embeddings

arXiv:2607. 05736v1 Announce Type: new Abstract: Molecular property prediction often relies on isolated data modalities, where continuous 3D graph neural networks (GNNs) struggle to efficiently capture long-range topological dependencies and exact macroscopic heuristics.

By Qiwei Han, Chi Zhou, Ruobing Wang, Zheng Ma