| abstract |
The present invention relates to a chelate of formula (I) which is suitable for labeling a bioactive substance in solution, characterized in that A is a reactive biomolecule binding group, Z <1> is hydrogen or a donor group d 'electrons, Z <2> is hydrogen or an electron donating group, Z <3> is hydrogen or an electron donating group, Z <4> is an electron donating group, Z <5 > is a substituent which contains a carboxylic acid group, a phosphoric acid group or a sulfonic acid group, X is a linker formed from one to ten parts, R <a>, R <b>, R <c> and R < d> are the same or different, and Ln is terbium, dysprosium, samarium or europium. |