| abstract |
The present invention provides an IR-absorbing naphthalocyanine dye of formula (I): wherein M is selected from Ga(A1); A1 is an axial ligand selected from OH, halogen (preferably Cl), OR3, a hydrophilic ligand and/or a ligand suitable for reducing cofacial interactions; R1 and R2 may be the same or different and are selected from hydrogen or C1-12 alkoxy (preferably C1-6 alkoxy); R3 is selected from C1-12 alkyl, C5-12 aryl, C5-12 arylalkyl or Si(Rx)(Ry)(Rz); and Rx, Ry and Rz may be the same or different and are selected from C1-12 alkyl, C5-12 aryl, C5-12 arylalkyl, C1-12 alkoxy, C5-12 aryloxy or C5-12 arylalkoxy; W is a hydrophilic group; n1 is 0, 1, 2 or 3; n2 is 0, 1, 2 or 3; n3 is 0, 1, 2 or 3; n4 is 0, 1, 2 or 3; provided that at least one of n1, n2, n3 or n4 is greater than 0. Dyes of this type are especially suitable for use in netpage and HyperlabelTM systems. |