Metal or metal alloy deposition composition and plating compound

A metal or metal alloy deposition composition, for electrolytic deposition of a metal or metal alloy layer, comprising

• a) at least one type of metal ions to be deposited,
• b) at least one plating compound comprising at least one structural unit represented by formula (1)
• wherein
• each R1 and R2 are independently selected from the group consisting of hydrogen and alkyl group;
• each X1 and X2 are independently selected from the group consisting of
• -a structural unit represented by formula (X-1)
• wherein
• Y1 is an alkanediyl group;
• each R11 is independently selected from the group consisting of hydrogen, alkyl group, aryl group, and alkaryl group;
• b is an integer ranging from 1 to 10;
• and
• -a structural unit represented by formula (X-2)
• wherein R21, R22, R23, R24 and R25 are independently selected from the group consisting of hydrogen, C1-C4-alkyl group;
• c is an integer selected from 1, 2, 3, 4, 5 and 6;
• d is an integer selected from 1 and 2;
• e is an integer selected from 1, 2, 3, 4, 5 and 6;
• with the proviso that at least one of X1 and X2 is a structural unit represented by formula (X-1);
• and a is an integer ranging from 1 to 10.