Described herein is an aqueous composition including tin ions and at least one compound of formula I where X1, X2 are independently selected from a linear or branched C1-C12 alkanediyl, R11 is a monovalent group of formula —(O—CH2—CHR41)m—OR42, R12, R13, R14 are independently selected from H, R11, and R40; R15 is selected from H, R11, R40 and —X4—N(R21)2, X4 is a divalent group selected from (a) a linear or branched C1 to C12 alkanediyl, and (b) formula —(O—CH2—CHR41)o—, R21 is selected from R11 and R40, R40 is a linear or branched C1-C20 alkyl, R41 is selected from H and a linear or branched C1 to C5 alkyl, R42 is selected from H and a linear or branched C1-C20 alkyl, n is an integer of from 1 to 6, m is an integer of from 2 to 250, and o is an integer of from 1 to 250.