Patent ID: 6908726

Claim:
An infrared absorbing compound of the structure: in which: Y 1 , Y 2 , and Y 3 are each independently hydrogen, halo, alkyl, phenyl, substituted phenyl, phenylamino, diphenylamino, or phenylthio; R 1 , R 2 , R 3 , and R 4 are each independently hydrogen, alkyl, or SO 3 − , with the proviso that two of R 1 , R 2 , R 3 , and R 4 are SO 3 − ; R 5 and R 6 are each independently alkyl, aryl, aralkyl, hydroxyalkyl, alkoxyalkyl, aminoalkyl, carboxyalkyl, or sulfoalkyl; R 7 and R 8 are each independently hydrogen, alkyl, or halo; Ar 1 and Ar 2 are each independently phenyl or substituted phenyl; Z 1 , and Z 2 are each independently a benzo group or a naphtho group; Z 3 and Z 4 are each independently two hydrogen atoms, a cyclohexene residue, or a cyclopentene residue; X 1 and X 2 are each independently S, O, NH, CH 2 , or C(CH 3 ) 2 ; and n, and n 2 are each independently 0 to 4.