Molecular Representations
Bar chart showing MolBERT ablation: combining MLM, PhysChem, and SMILES equivalence tasks gives best improvement

MolBERT: Auxiliary Tasks for Molecular BERT Models

MolBERT pre-trains a BERT model on SMILES strings using masked language modeling, SMILES equivalence, and physicochemical property prediction as auxiliary tasks, achieving state-of-the-art results on virtual screening and QSAR benchmarks.

Molecular Representations
Bar chart comparing nach0 vs T5-base across molecular captioning, Q/A, reaction prediction, retrosynthesis, and generation

nach0: A Multimodal Chemical and NLP Foundation Model

nach0 unifies natural language and SMILES-based chemical tasks in a single encoder-decoder model, achieving competitive results across molecular property prediction, reaction prediction, molecular generation, and biomedical NLP benchmarks.

Molecular Representations
Encoder-decoder architecture diagram for translating chemical names between English and Chinese with performance comparison bar chart

Neural Machine Translation of Chemical Nomenclature

This paper applies character-level CNN and LSTM encoder-decoder networks to translate chemical names between English and Chinese, comparing them against an existing rule-based tool.

Molecular Representations
Bar chart showing randomized SMILES generate more of GDB-13 chemical space than canonical SMILES across training set sizes

Randomized SMILES Improve Molecular Generative Models

An extensive benchmark showing that training RNN generative models with randomized (non-canonical) SMILES strings yields more uniform, complete, and closed molecular output domains than canonical SMILES.

Molecular Representations
Diagram showing SMILES string flowing through encoder to fixed-length fingerprint vector and back through decoder

Seq2seq Fingerprint: Unsupervised Molecular Embedding

A GRU-based sequence-to-sequence model that learns fixed-length molecular fingerprints by translating SMILES strings to themselves, enabling unsupervised representation learning for drug discovery tasks.

Molecular Representations
Bar chart comparing SMI-TED ROC-AUC scores against ChemBERTa, ChemBERTa-2, MoLFormer, and GROVER on BBBP and HIV

SMI-TED: Encoder-Decoder Foundation Models for Chemistry

SMI-TED introduces encoder-decoder chemical foundation models (289M parameters) pre-trained on 91 million PubChem molecules, achieving strong results across property prediction, reaction yield, and molecule generation benchmarks.

Molecular Representations
Bar chart comparing binding affinity scores across SMILES, AIS, and SMI+AIS hybrid tokenization strategies

SMI+AIS: Hybridizing SMILES with Environment Tokens

Proposes SMI+AIS, a hybrid molecular representation combining standard SMILES tokens with chemical-environment-aware Atom-In-SMILES tokens, demonstrating improved molecular generation for drug design targets.

Molecular Representations
Diagram showing Transformer encoder-decoder architecture converting SMILES strings into molecular fingerprints

SMILES Transformer: Low-Data Molecular Fingerprints

A Transformer-based encoder-decoder pre-trained on 861K SMILES from ChEMBL24 produces 1024-dimensional molecular fingerprints that outperform ECFP and graph convolutions on 5 of 10 MoleculeNet tasks in low-data settings.

Molecular Representations
Bar chart comparing Atom Pair Encoding vs BPE tokenization on MoleculeNet classification tasks

SMILES vs SELFIES Tokenization for Chemical LMs

Introduces Atom Pair Encoding (APE), a chemistry-aware tokenizer for SMILES and SELFIES, and shows it consistently outperforms Byte Pair Encoding in RoBERTa-based molecular property classification on BBBP, HIV, and Tox21 benchmarks.

Molecular Representations
Bar chart comparing SMILES-BERT accuracy against baselines on HIV, LogP, and PCBA tasks

SMILES-BERT: BERT-Style Pre-Training for Molecules

SMILES-BERT pre-trains a Transformer encoder on 18M+ SMILES from ZINC using a masked recovery task, then fine-tunes for molecular property prediction, outperforming prior methods on three datasets.

Molecular Representations
Visualization of tokenizer vocabulary coverage across chemical space

Smirk: Complete Tokenization for Molecular Models

Introduces Smirk and Smirk-GPE tokenizers that fully cover the OpenSMILES specification, proposes n-gram language models as low-cost proxies for evaluating tokenizer quality, and benchmarks 34 tokenizers across intrinsic and extrinsic metrics.

Molecular Representations
Bar chart showing SMILES Pair Encoding reduces mean sequence length from 40 to 6 tokens

SPE: Data-Driven SMILES Substructure Tokenization

Introduces SMILES Pair Encoding (SPE), a data-driven tokenization algorithm that learns high-frequency SMILES substrings from ChEMBL to produce shorter, chemically interpretable token sequences for deep learning.