Claims
- 1. A radiation-sensitive composition exhibiting upon exposure an internal gain comprising, in admixture,
- a compound containing a conjugated .pi.-bonding system capable of forming a tridentate chelate with cobalt(III), said compound being defined by one of the formula:
- Z.sup.2 --N.dbd.N--Z.sup.3,
- Z.sup.4 --CH.dbd.N--NH--Z.sup.5 or
- Z.sup.6 --CH.dbd.N--Z.sup.7
- wherein Z.sup.2, Z.sup.3, Z.sup.4, Z.sup.5, Z.sup.6 and Z.sup.7 are independently chosen from anong 2-hydroxy, carboxy or amino substituted naphthyl or phenyl; 2-pyridyl; 2-quinolinyl; 2-thiazolyl; 2-benzothiazolyl; 2-oxazolyl; and 2-benzoxazolyl groups, and are each capable of forming chelate ligands, and
- an inert cobalt(III) complex capable of being reduced by a cobalt(II) complex containing said chelating compound, whereby the cobalt(II) converts to a stable cobalt(III) complex,
- and a photoreductant capable of forming spontaneously when exposed to activating radiation, or upon subsequent application of heat, a reducing agent capable of reducing said inert cobalt(III) complex,
- less than 50 mole percent of any acid anions of said composition being those having pKa values greater than 3.5.
- 2. A composition according to claim 1 in which said photoreductant is chosen from the class consisting of quinone, disulfide, diazoanthrone, diazonium salt, diazophenanthrone, aromatic azide, acyloin, aromatic ketone, aromatic carbazide and diazosulfonate photoreductants.
- 3. A radiation-sensitive composition comprising, in admixture,
- (1) a compound containing a conjugated .pi.-bonding system capable of chelating with cobalt(III) said compound being selected from the group consisting of nitroso-arols, dithiooxamides, formazans, aromatic azo compounds, hydrazones and Schiff bases;
- (2) an inert cobalt(III) complex capable of being reduced by a cobalt(II) complex containing said chelating compounds, whereby the cobalt(II) converts to a stable cobalt(III) complex; and
- (3) a quinone photoreductant which is capable, spontaneously or upon subsequent application of heat, for photoreducing said inert complex, and which incorporates one or more labile hydrogen atoms;
- less than 50 mole percent of any acid anions of said composition being those having pKa values greater than 3.5.
- 4. A composition according to claim 3 in which said labile hydrogen atoms are attached to a carbon atom which is also bonded to the oxygen atom of any oxy substituent or the nitrogen atom of an amine substituent with the further provision that the carbon to hydrogen bond is the third or fourth bond removed from at least one quinone carbonyl bond.
- 5. An image-forming element as defined in claim 1 wherein said coating is a composite coating comprising two contiguous layers, one of which contains said quinone photoreductant and the other of which contains said cobalt(III)complex and said compound containing said II bonding system.
- 6. An image-forming element exhibiting upon exposure an internal gain, comprising
- a support, and
- as a coating thereon a radiation-sensitive layer comprising, in admixture,
- a compound containing a conjugated .pi.-bonding system capable of forming a tridentate chelate with cobalt(III), said compound being defined by one of the formulas:
- Z.sup.2 --N.dbd.N--Z.sup.3,
- Z.sup.4 --CH.dbd.N--NH--Z.sup.5 or
- Z.sup.6 --CH.dbd.N--Z.sup.7
- wherein Z.sup.2, Z.sup.3, Z.sup.4, Z.sup.5, Z.sup.6 and Z.sup.7 are independently chosen from among 2-hydroxy, carboxy or amino substituted naphthyl or phenyl; 2-pyridyl; 2-quinolinyl; 2-thiazolyl; 2-benzothiazolyl; 2-oxazolyl; and 2-benzoxazolyl groups, and are each capable of forming chelate ligands,
- an inert cobalt(III) complex capable of being reduced by a cobalt(II) complex containing said chelating compound, whereby the cobalt(II) converts to a stable cobalt(III) complex,
- and a photoreductant capable of forming spontaneously when exposed to activating radiation, or upon subsequent application of heat, a reducing agent capable of reducing said inert cobalt(III) complex,
- less than 50 mole percent of any acid anions of said coating being those having pKa values greater than 3.5.
- 7. An image-forming element according to claim 6 in which said photoreductant is chosen from the class consisting of quinone, disulfide, diazoanthrone, diazonium salt, diazophenanthrone, aromatic azide, acyloin, aromatic ketone, aromatic carbazide and diazosulfonate photoreductants.
- 8. An image-forming element according to claim 7 wherein said photoreductant is a quinone, and further including an adjuvant capable of producing a labile hydrogen atom for reduction of said photoreductant.
- 9. An image-forming element according to claim 8 in which said labile hydrogen atoms are attached to a carbon atom which is also bonded to the oxygen atom of an oxy substituent or the nitrogen atom of an amine substituent with the further provision that the carbon to hydrogen bond is the third or fourth bond removed from at least one quinone carbonyl bond.
- 10. An image-forming element according to claim 8 in which said adjuvant is present in a concentration of at least 0.5 mole per mole of said photoreductant.
- 11. An image-forming element comprising
- a support, and
- as a coating thereon, a radiation-sensitive layer comprising, in admixture,
- (1) a compound containing a conjugated .pi.-bonding system capable of chelating with cobalt(III), said compound being selected from the group consisting of nitroso-arols, dithiooxamides, formazans, aromatic azo compounds, hydrazones and Schiff bases;
- (2) an inert cobalt(III) complex capable of being reduced by a cobalt(II) complex containing said chelating compound, whereby the cobalt(II) converts to a stable cobalt(III) complex; and
- (3) a quinone photoreductant which is capable, spontaneously or upon subsequent application of heat, of photoreducing said inert complex, and which incorporates one or more labile hydrogen atoms,
- less than 50 mole percent of any acid anions of said coating being those having pKa values greater than 3.5.
- 12. An image-forming element according to claim 11 in which said labile hydrogen atoms are attached to a carbon atom which is also bonded to the oxygen atom of any oxy substituent or the nitrogen atom of an amine substituent with the further provision that the carbon to hydrogen bond is the third or fourth bond removed from at least one quinone carbonyl bond.
RELATION TO OTHER APPLICATIONS
This is a division of application Ser. No. 627,416, filed Oct. 30, 1975, now U.S. Pat. No. 4,075,019 which application is a continuation-in-part application of U.S. Ser. No. 461,172 filed Apr. 15, 1974, now abandoned.
US Referenced Citations (13)
Foreign Referenced Citations (1)
Number |
Date |
Country |
908299 |
Oct 1962 |
GBX |
Non-Patent Literature Citations (4)
Entry |
DoMinh, "A Novel Gain Imaging Process", Unconventional Photographic Systems, Symposium IV, 11/20/1975. |
Endicott, J. F., et al., J. Am. Chem. Soc., 87, pp. 3348-3357, 8/1965. |
Lalor, G. C., J. Inorganic Nuclear Chem. 30, pp. 1783-1789, 1969. |
Color Index, 3rd Ed., vol. 4, Society of Dyers and Colorists, 1971, pp. 4020, 4049, 4051, 4064. |
Divisions (1)
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Parent |
627416 |
Oct 1975 |
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Continuation in Parts (1)
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461172 |
Apr 1974 |
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