Monomeric building blocks for labeling peptide nucleic acids

A nucleic acid-binding oligomer which has a structure of the general formula (III):

• in which:
• n is an integer of at least 3,
• x is an integer from 2 to n−1,
• each of the groups B1 to Bn is a nitrogen base as previously defined,
• each of the groups C1-Cn has the meaning (CR6R7)y, where R6 is hydrogen and R7 is selected from the group consisting of the side chains of naturally occurring alpha-amino acids, or R6 and R7 are independently selected from the group consisting of hydrogen, C1-C6-alkyl, aryl, aralkyl, heteroaryl, hydroxyl, C1-C6-alkoxy, C1-C6-alkylthio, NR3R4 and SR5, where R3 and R4 are as defined below and R5 is hydrogen, C1-C6-alkyl or C1-C6-alkyl which is substituted by hydroxyl, C1-C6-alkoxy or C1-C6-alkylthio, or R6 and R7 together form an alicyclic system or heterocyclic system, or C1-Cn is CO, CS or CNR3;
• each of the radicals D1-Dn has the meaning (CR6R7)2, where R6 and R7 are as defined before, and y and z are integers of from 0 to 10, where the sum of y+z is at least 2;
• each of the radicals G1-Gn−1 has the meaning —NR3CO, NR3CS—, —NR3—SO— or —NR3SO2 in any orientation, where R3 is as defined below;
• each of the radicals A1-An and E1-En is selected such that:
• (a) A1-An is a group of the formula (IIIa), (IIIb), (IIIc) or (IIId), and E1-En is N or R3N+, or
• (b) A1-An is a group of the formula (IIId), and E1-En is CH:
• in which:
• X is 0, S, Se, NR3, CH2 or C(CH3)2,
• Y is a single bond, O, S or NR4,
• p and q are in each case an integer of from 0 to 5,
• r and s are in each case integers of from 0 to 5,
• each of the radicals R8 and R9 is selected independently from the group consisting of hydrogen, hydroxyl, amine, halogen, C1-C4-alkoxy, C1-C4-alkylthio and unsubstituted or substituted C1-C4-alkyl, where the substituents are selected from hydroxyl, C1-C4-alkoxy or C1-C4-alkylthio groups;
• each of the radicals R3 and R4 is selected independently from the group consisting of hydrogen, C1-C4-alkyl which is unsubstituted or substituted by hydroxyl or C1-C4-alkoxy or C1-C4-alkylthio, hyroxyl, C1-C6-alkoxy, C1-C6-alkylthio and amine;
• Q′ and I′ are selected independently from the group consisting of NH2, CONH2, COOH, hydrogen, C1-C6-alkyl, O(C1-C6)-alkyl, an amine which is blocked by a protecting group, labeling groups, intercalators, chelators, peptides, proteins, carbohydrates, lipids, steroids, nucleosides, nucleotides, nucleoside-diphosphates, nucleosidetriphosphates, oligo-nucleotides, including oligoribonucleotides and oligodeoxyribonucleotides, oligonucleosides and soluble and insoluble polymers and also nucleic acid-binding groups, and
• X1 and Y1 is in each case an integer of from 0 to 10, with the compound being such that ruthenium (bipyridyl)3 is present at at least one nitrogen base and/or at a position in the peptide backbone.