A compound including: a binding portion including a dithio C1-C16 alkyl moiety; an end portion including an unsubstituted C6-C40 aryl group, an unsubstituted C2-C10 alkyl group, or an unsubstituted C7-C50 aryl alkyl group; and a hydrophilic linker including oxygen, the hydrophilic linker connecting the binding position and the end portion. The binding portion and the linker are connected by an ester linkage. A composition comprising a quantum dot coordinated with the compound.