Patent ID: 8012458

Claim:
A process comprising combining in an organic solvent a lanthanide ester and a compound represented by the formula wherein R 1 is heteroaryl; R 2 is aminoalkyl; resulting in a solution of tris-amidato-lanthanide chelate represented by structure III wherein Ln 3+ designates lanthanide, R 1 is heteroaryl; R 2 is aminoalkyl; and, addition of a neutrally charged coordinating ligand to the solution of tris-amidato-lanthanide chelate providing a lanthanide chelate represented by structure I or structure II as shown below: wherein Ln 3+ designates lanthanide, R 1 is heteroaryl; R 2 is aminoalkyl; M is tri-phenyl phosphine oxide, M′ is 1,10-phenanthroline, a=1 or 2; and the neutrally charged coordinating ligand is tri-phenyl phosphine oxide or 1,10-phenanthroline.