Version 1.3.9 of the Mobile Molecular DataSheet (MMDS) for iOS has just come out, and it brings a nice improvement to molecule sketching: there is now an action button for converting a selected terminal group into an inline abbreviation, which is automatically set to its molecular formula:

The action subsumes the selected atoms into an inline abbreviation, so the original chemical structure is preserved. Representing formulae within a molecular structure is a very common way to condense representations of a structure, and using this method ensures that the structural nuances are not lost, i.e. the abbreviation can be restored by re-expanding it, and the overall molecular formula for the structure is still calculated correctly.

The formula is composed using several simple meta-characters: in the above example, the phenyl group is rendered as C₆H₅, which is encoded internally as “C{6}|H{5}”. The curly braces (“{}”) surround the subscripts, and the vertical bar (“|”) separates groups, so that they can be rendered in reverse order when displayed backwards. The abbreviation can be edited by double-tapping on the abbreviation atom.

Another feature that was introduced with this version of MMDS is integration with the SPRESImobile app, from within the Search molecule submenu, as shown on the right. Selecting this destination will use the selected structure to search the SPRESI ChemReact database. The app is free, and is available from the iTunes AppStore. SPRESImobile is the result of a collaboration between InfoChem, Eidogen-Sertanty and Molecular Materials Informatics: if you have an iOS device, you should download it as soon as you have updated your copy of MMDS!