+ninstructs to repeat the monomer unit n times by connecting the O-atom of one unit to the open bond at the Si atom of the next unit. Another illustration has been given with poly(3-hexylthiophene). Ring molecules that are based on a structural repeat unit, can be encoded with OPAM
+r. Metal-ligand systems such as complexes with ambidentate ligands can be encoded with OPAM
+L. Sets of molecules can be encoded with OPAM
+Y, for example, classes of alkyl-substituted compounds with
 Axel Drefahl: CurlySMILES: a chemical language to customize and annotate encodings of molecular and nanodevice structures. Journal of Cheminformatics 2011, 3:1.
 Axel Drefahl: CurlySMILES: molecular detail annotation [www.axeleratio.com/csm/proj/operatann.htm].