Non-heterocyclic oxonol infrared radiation sensitive compounds

Details Non-heterocyclic oxonol infrared radiation sensitive compounds Non-heterocyclic oxonol infrared radiation sensitive compounds

2000-06-08

2001-06-19

Raymond, Richard L. (Department: 1624)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

C546S348000, C558S390000, C558S401000, C558S403000

Reexamination Certificate

active

06248893

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to novel compounds that are infrared radiation sensitive. More particularly, this invention relates to novel non-heterocyclic oxonol compounds that are sensitive at 700 nm or higher wavelengths in water or water-miscible organic solvents.
BACKGROUND OF THE INVENTION
Particulate compounds that absorb at various wavelengths have been used in photographic silver halide materials for many years. For example, such compounds have been used as “filter” dyes to absorb electromagnetic radiation (“light”) from different regions of the electromagnetic spectrum, such as red, blue, green, ultraviolet and infrared regions. These filter dyes are often required to perform the function of absorbing light during exposure of the material so as to prevent or at least inhibit light of a particular region of the spectrum from reaching at least one of the radiation-sensitive layers of the material.
Particulate filter dyes can be designed with various features to facilitate their use and/or immobilization in photographic materials, as described for example in U.S. Pat. No. 5,213,956 (Diehl et al).
There is a need in the photographic industry for compounds that absorb in the near infrared and infrared regions of the electromagnetic spectrum for various purposes. Such materials can be used, for example, to absorb heat and to initiate or facilitate imaging in lithographic printing plates. However, such compounds (that is, IR dye sensitizers) must be compatible with other components of imaging formulations used in such printing plates.
Organic dye salts, by nature, are often partially soluble in water or alcoholic coating solvents and are thus preferred as IR dye sensitizers in lithographic plate imaging compositions. However, many such salts have been found to be unacceptable because of insufficient solubility, because they react with the charged polymer to form hydrophobic products that can result in scummed or toned images, or because they offer insufficient thermal sensitization in imaging members. In particular, there is a need to have IR dye sensitizers that are compatible with thiosulfate polymers, such as those described in copending and commonly assigned U.S. Ser. No., 09/156,833 filed Sep. 18, 1998, now U.S. Pat. No. 5,985,514.
SUMMARY OF THE INVENTION
We have discovered that certain non-heterocyclic oxonol compounds are useful as infrared radiation absorbing compounds in lithographic printing plates and other imaging elements describes herein. These novel compounds are soluble in water or water-miscible organic solvents, absorb radiation and have a &lgr;
max
greater than 700 nm as measured in water or a water-miscible organic solvent. These compounds are also represented by Structure DYE shown as follows:
wherein R is a secondary or tertiary amine containing no heterocyclic group, R
1
and R
2
are independently carbocyclic aromatic groups, and M
+
is a monovalent cation.
These compounds have been found not only to have the desired infrared radiation absorption characteristics but also to be soluble in water or water-miscible organic solvents that are often used to formulate and coat lithographic printing plate imaging compositions. In addition, these compounds are compatible with negatively charged polymers that may be present in those compositions (for example, anionic polymers used for imaging such as those described in U.S. Ser. No. 09/156,833 noted above, now U.S. Pat. No. 5,985,514). In other words, no precipitates are formed when such compounds and polymers are mixed.
A preferred use of the compounds of this invention in printing plates is described in copending and commonly assigned U.S. Ser. No. 09/444,695 filed on Nov. 22, 1999 by DoMinh et al.
The compounds can also be used as filter dyes that are compatible with components in color and black-and-white photographic silver halide layers, and that do not adversely affect the sensitometric properties of such layers. We have also found that the compounds have desirable raw stock keeping.
DETAILED DESCRIPTION OF THE INVENTION
The compounds of this invention are oxonol infrared radiation sensitive dyes (“IR dyes”) that comprise a methine linkage conjugated with 2 carbocyclic or aliphatic groups, one of which is negatively charged. They are soluble in water or any of the water-miscible organic solvents that are commonly useful for preparing heat-sensitive lithographic imaging compositions (for example, methanol, ethanol, isopropanol, 1-methoxy-2-propanol, methyl ethyl ketone, tetrahydrofuran, acetonitrile, butyrolactone and acetone). Preferably, the IR dyes are soluble in either water or methanol, or a mixture of water and methanol. Solubility in water or the water-miscible organic solvents means that the oxonol IR dye can be dissolved at a concentration of at least 0.5 g/l at room temperature.
The oxonol IR dyes are sensitive to radiation in the near-infrared and infrared regions of the electromagnetic spectrum. Thus, they generally have a &lgr;
max
at or above 700 nm (preferably a &lgr;
max
of from about 750 to about 900 nm, and more preferably a &lgr;
max
of from about 800 to about 850 nm).
The oxonol IR dyes can be synthesized using general procedures described by Hamer in
The Cyanine Dyes and Related Compounds,
Interscience Publishers, 1964. A preferred synthetic method is described below.
The oxonol IR dyes of this invention can be represented by Structure DYE shown as follows:
wherein R is a secondary or tertiary amine. The nitrogen atom of this amine group can be substituted, for example, with one or more substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms (methyl, ethyl, isopropyl, t-butyl, hexyl, dodecyl, aminoethyl, methylsulfonaminoethyl and other groups readily apparent to one skilled in the art), substituted or unsubstituted aryl groups (such as phenyl, naphthyl, xylyl, m-carboxyphenyl and others than would be readily apparent to one skilled in the art), or a ═C(N<)— group.
Preferably, R is a secondary amine having at least one phenyl substituent, or at least one substituted or unsubstituted alkyl group having 1 to 3 carbon atoms.
R
1
and R
2
are independently substituted or unsubstituted carbocyclic aromatic groups having from 5 to 12 atoms in the aromatic ring. Preferably, R
1
and R
2
represent the same aromatic carbocyclic group. Useful aromatic groups include, but are not limited to, substituted or unsubstituted phenyl groups or substituted or unsubstituted naphthyl groups. These aromatic groups can be substituted with one or more amino, methoxy, carboxy, sulfo, sulfonamido or alkylsulfonyl groups. Preferably, when R
1
and R
2
are substituted, they each have one or more of the same substituents.
The oxonol IR dyes of this invention contain no heterocyclic groups in R, R
1
or R
2
.
M
+
is a suitable monovalent cation such as an alkali metal ion (lithium, sodium or potassium), an ammonium ion, a trialkylammonium ion (such as trimethylammonium, trimethylammonium or tributylammonium ions), a tetraalkylammonium ion (such as tetramethylammonium ion), pyridinium ion or tetramethyl guanidinium ion.
Examples of oxonol IR dyes of this invention include, but are not limited to, the following compounds:
Further oxonol IR dyes are defined in reference to Structure DYE wherein R
1
and R
2
are each a phenyl group, as follows:
IR Dye
R
M
+
DYE 13

DYE 14

DYE 15

DYE 16

DYE 17
Oxonol IR Dye 2 was prepared using the following synthetic scheme that is generally useful for all of the compounds of this invention.
A sample of Intermediate A (23.6 g, 0.1 moles) and trimethoxypropene (33 g) were added into acetic acid (200 ml). The solution went homogeneous and then after 15 minutes at room temperature a yellow solid began to separate from the mixture. The resulting Intermediate B was collected by filtration after 1 hour (21 g, 70%). Intermediate B was used without further purification in the next step.
A sample of Intermediate B (30.5 g, 0.100 moles) and N-(1-cyclopentenyl-1-yl)-diphenylammonium tetrafluoroborate (16 g, 0.05 moles)

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