Stable, water-soluble near infrared dyes
The synthesis of stable, water-soluble tris and tetrakis aminium dyes. More particularly, carboxylic-acid modified tris and tetrakis dye intermediates, as well as salts and near-infrared dyes formed therefrom, as well as compositions including the dyes.
1. A compound of the formula:
where R is dimethylene or where R has the formula R 3 CH 2 CH 2 — and R 3 is methylene or a C 2 to C 10 polymethylene group of the formula —(CH 2 ) n — where 2≦n≦10.
2. A compound of claim 1 which has the formula:
3. A salt produced from the compound of claim 1 , the salt having the formula:
wherein R 1 =Na + , K + , NH 4 + , (CH 3 ) 4 N + , (CH 3 ) 3 NH + , (R 2 ) 3 NH + or R 2 NH 4 + , and
R 2 =CH 3 (CH 2 ) n , wherein n=2 to 10.
4. A dye produced from the salt of claim 3 , the dye having the formula:
wherein X=NO 3 − , SbF 6 − , PF 6 − , BF 4 − , I − , Cl − , Br − or CH 3 SO 3 − .
5. A water-soluble polymeric composition comprising a blend of the dye of claim 4 and a water-soluble polymer.
6. An aqueous composition comprising the dye of claim 4 , a water-soluble polymer and water.