Demos > Mechanism Matching

The ability to match molecules is an important part of any chemical software system. ChemDoodle uses advanced graph isomorphism algorithms to quickly and completely compare two structures (or groups of structures). Isomorphism algorithms provide accurate comparison information regardless of how the user drew the correct structure (as opposed to SMILES comparison, for instance). In addition, ChemDoodle also allows for superstructure and substructure matching, query matching and similarity between structures. This allows us to create advanced chemical systems, please see our ChemStack demo for a nice example.

Beyond structural comparisons, ChemDoodle provides the ability to compare movement of electrons within and between structures, in essence we can compare mechanism drawings. This demo shows off this feature. Draw any of the mechanisms shown to the right and when drawn correctly, they will be marked as a MATCH!. If only part of the mechanism is drawn, it will be marked as a PARTIAL MATCH!. Note that the Br₂ mechanism uses single electron pushers and the last two mechanisms are identical, but use different representations of the benzene ring to show they should match each other. You can add your own mechanisms for matching by drawing them in the sketcher and clicking either of the two blank components below the sketcher.

You can control whether CIP stereochemical configurations are enforced in matching by selecting the Enforce Stereochemistry in Matching checkbox above the sketcher. Note this will correctly match double bonds using CIP configurations so E→E and Z→Z, while you may confusingly see cis or trans input have partial matches with the opposite cis/trans configuration in larger structures because CIP is not the same as cis/trans.

Imagine using these algorithms in your own educational eBook or in an advanced reaction database! Enjoy! Contact iChemLabs today for details.