Pyridinium compounds, a synthesis method therefor, metal or metal alloy plating baths containing said pyridinium compounds and a method for use of said metal or metal alloy plating baths

A compound comprising a building block according to formula (I)

• wherein each A represents a unit independently selected from the following formulae (A1) and (A2)
• wherein
• Ra1, Ra2, Ra3 and Ra5 are each selected independently from the group consisting of C1-C12-alkanediyl and —(CH2)c—[CH(Ra6)—CH2—O]d—(CH2)e— wherein c is an integer ranging from 0 to 3;
• d is an integer ranging from 1 to 100;
• e is an integer ranging from 1 to 3;
• each Ra6 is independently from each other selected from the group consisting of hydrogen, alkyl, aryl and aralkyl;
• each Ra4 is independently selected from the group consisting of alkanediyl, arenediyl and —(CH2)f—[CH(Ra7)—CH2—O]g—(CH2)h—, wherein f is an integer ranging from 0 to 3;
• g is an integer ranging from 1 to 100;
• h is an integer ranging from 1 to 3;
• each Ra7 is independently from each other selected from the group consisting of hydrogen, alkyl, aryl and aralkyl;
• each X1 and X2 are independently selected from the group consisting of
• wherein Z is selected from —CH2—, O, S;
• z and z′ are integers independently ranging from 1 to 6, each Ra8 and Ra9 are independently selected from the group consisting of hydrogen, alkyl, aryl, aralkyl and —CH2—CH2—(OCH2CH2)y—OH wherein y is an integer from 1 to 4;
• each Y1, Y2 and Y3 are independently selected from the group consisting of O and) N(Ra10) wherein each Ra10 is independently selected from the group consisting of hydrogen, alkyl, aryl and aralkyl;
• a is an integer ranging from 1 to 40;
• and
• each D is independently selected from the group consisting of —CH2—CH(OH)—CH2—, —CH2—CH(SH)—CH2—, —(CH2)i—[CH(Rd1)—CH2—O]j—(CH2)k— and —CH2—CH(OH)—(CH2)l—[CH(Rd2)—CH2—O]m—(CH2)n—CH(OH)—CH2—
• wherein i is an integer ranging from 0 to 3;
• j is an integer ranging from 1 to 100;
• k is an integer ranging from 1 to 3;
• each Rd1 is independently from each other selected from the group consisting of hydrogen, alkyl, aryl and aralkyl;
• l is an integer ranging from 1 to 3;
• m is an integer ranging from 1 to 100;
• n is an integer ranging from 1 to 3;
• each Rd2 is independently from each other selected from the group consisting of hydrogen, alkyl, aryl and aralkyl.