Phthalamide-lanthanide complexes for use as luminescent markers

A compound having a structure according to Formula I:

• wherein,
• R1, R2, R4, R5, R6, R7, R10 and R20 are members independently selected from the group consisting of H, alkyl and substituted alkyl groups,
• wherein, two or more of R2, R4, R5, R7 and, when R3 is substituted alkyl, a substituent of R3 are optionally adjoined by at least one linker moiety to form at least one ring;
• R3, R8 and R9 are members independently selected from the group consisting of alkyl, substituted alkyl, aryl and substituted aryl groups;
• R11, R12, R13, R21, R22 and R23 are members independently selected from alkyl, substituted alkyl, H, —NR14R15, —NO2, —OR16, —COO17,
• wherein R14, R15, R16, and R17 are members independently selected from the group consisting of H, alkyl, and substituted alkyl, wherein R12 can optionally form a ring with R11, R13, or both, and R22 can optionally form a ring with R21, R23, or both, said rings being members independently selected from the group of ring systems consisting of cyclic alkyl, substituted cyclic alkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, heterocyclyl and substituted heterocyclyl ring systems;
• and
• Q1 is —OR18;
• Q2 is —OR19;
• wherein R18 and R19 are members independently selected from H, an enzymatically labile group, a hydrolytically labile group and a single negative charge;
• a is 0 or 1, with a proviso that when a is 0, N2′ is covalently attached directly to carbonyl group 2′;
• and
• z is 0 or 1, with a proviso that when z is 0, N1′ is covalently attached directly to carbonyl group 1′
• wherein said compound is covalently attached to a member selected from a receptor and a drug.