Patent ID: 8685276

Claim:
Aqueous inkjet ink composition comprising at least one recrystallized luminescent lanthanide complex of the formula: M 3 [Ln(A) 3 ] wherein M is chosen from the alkali cations Li + , Na + , K + , Rb + and Cs + and mixtures thereof; Ln is chosen from the trivalent rare-earth cations of Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb and mixtures thereof; and wherein A is a dinegatively charged, tridentate 5- or 6-membered heteroaryl ligand selected from the group consisting of pyridine, imidazole, triazole, pyrazole, and pyrazine, bearing at least one carboxylic group, and wherein no excessive ligand A in free form is present in the aqueous inkjet composition.