Novel Imidazolium Salts and Carbene Metal Complexes Based Thereon for Use as Bioanalytical Markers for Biomolecules

Imidazolium salts of the general formula I,

• wherein b, l, m, n, and q, where applicable, are the same or different and each is independent of each other and zero or 1, and o, p, and r, where applicable, are zero;
• and
• X− is an anion;
• R is chosen from the group consisting of C5-C15-aryl and C4-C14-hetaryl and a is zero;
• R1 and R2 are the same or different and open chained, branched, or unbranched or are part of a ring or a ring system and are chosen from the group consisting of hydrogen, C1-C12-n-alkyl, C3-C12-branched alkyl, C3-C12-cycloalkyl, C2-C12-alkenyl, C7-C20-arylalkyl, and C5-C14-aryl,
• which itself is either the same or differently substituted by one or more branched or unbranched C1-C3-alkyl groups, wherein the cyclic and aromatic systems are single rings or several condensed, annelated, or isolated rings or form a ring system together with the imidazolium ring of the structure according to formula I;
• R3 is chosen from the group consisting of —NH2, —COOH, —CONH2, and —COOR″, wherein R″ is C1-C6-n-alkyl;
• R4 is hydrogen or R5, wherein R5 is an imidazolium ring of formula II,
• wherein q is zero or 1 and r is zero;
• and
• R6 is the same or different to R1 and R2 and chosen from the same group as R1 and R2.