Percepta: Interpreting nitro groups in Percepta vs. ChemSketch

Description
Different cheminformatics tools can represent nitro groups (–NO2) in alternative valence forms. Some drawing styles that look correct visually may trigger valence or charge warnings in other software or when used as input to prediction engines such as Percepta.

Solution

• In ChemSketch, draw nitro groups using the standard nitro template or a recommended valence form (typically –N(=O)=O with appropriate charges).
• Avoid uncommon or ambiguous representations (for example, missing charges or incorrect valence on nitrogen).
• If a structure imported from another tool shows nitro groups with warnings:
  • Clean the structure in ChemSketch (Structure → Clean or similar).
  • Re‑draw nitro groups using ChemSketch’s own nitro templates.
• Before sending structures to Percepta:
  • Run a quick structure check in ChemSketch to ensure there are no valence errors.
  • Save the structure as MOL/SDF or SMILES from ChemSketch, then load into Percepta.
• If warnings persist in Percepta:
  • Double‑check the nitro representation and charges.
  • Confirm that atoms are correctly typed (N vs N+, O vs O–).