Synthetically expedient water-dispersible IR dyes

1. An IR-absorbing naphthalocyanine dye of formula (I), said dye being contained in an water-based inkjet ink:

wherein

M is selected from Si(A 1 )(A 2 ), Ge(A 1 )(A 2 ), Ga(A 1 ), Mg, Al(A 1 ), TiO, Ti(A 1 )(A 2 ), ZrO, Zr(A 1 )(A 2 ), VO, V(A 1 )(A 2 ), Mn, Mn(A 1 ), Fe, Fe(A 1 ), Co, Ni, Cu, Zn, Sn, Sn(A 1 )(A 2 ), Pb, Pb(A 1 )(A 2 ), Pd and Pt

A 1 and A 2 are axial ligands, which may be the same or different, and are selected from —OH, halogen or; —OR 3 ;

R 1 and R 2 are selected from H or C 1-12 alkoxy;

R 3 is selected from C 1-12 alkyl, C 1-12 aryl, C 5-12 arylalkyl or Si(R x )(R y )(R z ); and

R x , R y and R z may be the same or different and are selected from C 5-12 alkyl, C 5-12 aryl, C 5-12 arylalkyl, C 1-12 alkoxy, C 5-12 aryloxy or C 5-12 arylalkoxy;

W is selected from a sulfonic acid group (including salts thereof) or a sulfonamide 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.

2. The dye of claim 1 , W is —SO 3 H or —SO 3 Z, wherein Z is Li, Na or K.

3. The dye of claim 1 , wherein W is —SO 2 NR p R q , wherein R p and R q are independently selected from H, C 1-18 alkyl, C 6-12 arylalkyl, C 6-12 aryl or —(CH 2 CH 2 O) e R e , wherein e is an integer from 2 to 3 and R e is H, C 1-8 alkyl or C(O)C 1-8 alkyl.

4. The dye of claim 1 , wherein W is —SO 2 NHR p and R p is of formula (V):

wherein:

R j is H, C 1-12 alkoxy or —(OCH 2 CH 2 ) d OR d ;

d is an integer from 2 to 3; and

R d is H, C 1-8 alkyl or C(O)C 1-8 alkyl.

5. The dye of claim 1 , wherein R 1 and R 2 are both H.

6. The dye of claim 1 , wherein R 1 and R 2 are both C 1-18 alkoxy.

7. The dye of claim 1 , wherein M is Si(A 1 )(A 2 ), Ge(A 1 )(A 2 ), Ga(A 1 ), Al(A 1 ), Mn(A 1 ), Fe(A 1 ) or Sn(A 1 )(A 2 ).

8. The dye of claim 1 , wherein M is Al(A 1 ).

9. The dye of claim 8 , wherein A 1 and/or A 2 is Cl or OH.