The term ???alkanediyl??? when used without the ???substituted??? modifier refers to a non-aromatic divalent group, wherein the alkanediyl group is attached with two ??-bonds, with one or two saturated carbon atom(s) as the point(s) of attachment, a linear or branched, cyclo, cyclic or acyclic structure, no carbon-carbon double or triple bonds, and no atoms other than carbon and hydrogen.