CurlySMILES: annotation dictionary

An annotated SMILES notation is a SMILES notation enhanced by annotation code. Annotation code that has a two-character annotation marker, AM, can optionally be followed by an annotation dictionary. Such an annotation has the general format:

{AMk₁=v₁;k₂=v₂;...;k_n=v_n}

The annotation dictionary is a semicolon-separated list of key/value pairs, k_i/v_i, with i=1,2,...,n. Each value is separated from its key by an equal sign.

For example, the CurlySMILES notation

O{IMc=[Na+].[Cl-]}

encodes water that contains an impurity of sodium chloride. Here, IM marks an annotation specifying an impurity or dopant, which, in this case, is itself encoded by CurlySMILES (or simply SMILES) as indicated by key c in the annotation dictionary.

The CurlySMILES notation

[Na+].[Cl-]{dsc=O}

encodes sodium chloride dissolved in water, using the state and shape annotation marker ds to indicate dissolution, while the solvent is entered in SMILES code as the value of key c. Notice that both examples illustrate component annotations and apply to the whole structure.

See the complete list of keys and their associated values: annotation dictionary keys.