s, substituted aryls, aralkyls, C1-6 heteroalkyls, substituted C1-6 heteroalkyls, C1-6 alkoxy, phenoxy and C1-6 heteroalkoxy; [0057] Ar is a moiety which when included in Formula (I) forms a multi-substituted aromatic hydrocarbon or a multi-substituted heterocyclic group; and [0058] Broadly, D is a moiety that is a leaving group, or a residue of a compound to be delivered into a cell.