JPH06130541A - Silver halide photographic emulsion - Google Patents

Abstract

PURPOSE:To provide the spectral hypersensitizer capable of effectively enhancing spectral sensitivity of the silver halide photographic emulsion by specifying the compound to be added. CONSTITUTION:The silver halide emulsion contains the thiosali-cylic acid derivative having a group of a chelating agent in the molecule and it is represented by formula in which Z is H, a metal ion, or acyl; each of R<1> and R<2> is, independently, H, alkyl, or alkoxy; and X is a bonding group necessary to form a 15-, 18-, or 12-membered ring. This compound is obtained by (1) formylating a benzocrown-ether as a main starting nucleus by the Wills-Meier reaction, (2) nitrating and (3) oxidizing the formyl group with KMnO4, (4) reducing the obtained nitrobenzoic acid derivative with Fe to obtain an anthranylacid derivative, (5) diazotizing this amino form, (6) allowing the product to react with potassium xanthate, and finally, (7) reducing this product with sodium hydrosulfite.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION Spectral sensitization is a particularly important technique in the production of silver halide photographic emulsions. Spectral sensitizers are organic dyes called cyanine and merocyanine, and are also known as color sensitizers. In recent years, demands for using a laser light source and increasing sensitivity have been increasing, and it has become difficult to sensitize a dye alone. It is known that a combination of a dye and another organic compound increases the efficiency as compared with the case of using the dye alone, and is called supersensitization or supersensitization. An organic compound having such properties is called a supersensitizer. For supersensitization, J aggregates of dyes are often used, and use of this technology is very effective for supporting a laser light source with high sensitivity.

[0002]

2. Description of the Related Art The mechanism of supersensitization is, for example, James, TH, T.
he Theory of the photographic process P.259-261, Ma
cmillan Publishing (New York 1977) and Sturge J.
M., Neblettes Handbook of Photography P.92-96, Lit
ton Education Publishing (NewYork 1977), Gilman, J
rPB, Photographic Science and Engineering 18 418
-428 (1974) JW Mitchell., J. Imag.sci 30 102 (1986)
Etc. in detail.

The contents can be roughly classified into the following three types. (1) Addition of a supersensitizer increases the light absorption of the dye (including the formation of J-aggregates). (2) To promote the adsorption of dye on the surface of silver halide grains. (3) Electron transfer from the photoexcited dye to the silver halide conduction band occurs, but the dye sensitized hole is trapped by the supersensitizer. This is the so-called hole trapping theory. In order for supersensitization to occur by the mechanism (3), the oxidation potential of the supersensitizer (hereinafter referred to as Eox) must be smaller than that of the sensitizing dye. One of the well-known compounds satisfying this condition is a dialkylaminostyryl-based compound.
With the exception of dialkylaminostyryl bases, most of this type of supersensitizer is the sensitizing dye itself, and many combinations of two or more sensitizing dyes fall into this hole trapping mechanism.

However, there are compounds known to trap dye holes even though Eox is greater than that of the dye. For example Tani T, Photographi
In C science and Engineering 23 240 (1979), 4-hydroxy-6-methyl-1,3,3a, 7-tetraazaindene (TAI) traps dye holes and causes supersensitization. Proven using. Further, JP-A-51-81613 discloses that a benzotriazole derivative serves as a supersensitizer, but it seems that such a high effect is not obtained.

Further, JP-A-51-77224 reports that 1-phenyl-5-mercaptotetrazole (PMT) causes supersensitization. Although not described in detail, the mechanism of supersensitization seems to be (3) or both (1) and (3). Further, JP-A-63-1598
40, it is reported that good results can be obtained by combining a heterocyclic mercapto compound represented by PMT with a chelating agent such as EDTA. This method has a markedly higher effect than the method described above, but it is difficult to control the addition amount of the chelating agent and the heterocyclic mercapto compound because they are different from each other in terms of their ease of adsorption to the AgX surface. In addition, according to the mechanisms of both (1) and (3), naturally, the chelating agent and the mercapto compound should be closer to each other on the AgX surface, so that the effect of supersensitization should be higher.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an effective supersensitizer for silver halide photographic emulsion.

[0007]

Means for Solving the Problems As a result of intensive studies by the present inventors, they found that thiosalicylic acid derivatized 2 having a chelating moiety in the molecule is an effective supersensitizer. It was

[0008]

[Chemical 2]

(In the formula, Z is a hydrogen atom, a metal ion or an acyl group, and R ¹ and R ² may be the same or different,
Each represents a hydrogen atom, an alkyl group, or an alkoxy group, and X is a divalent linking group, which forms a 15, 18, or 21-membered ring. )

Representative specific examples of the supersensitizer of the present invention are shown below.

[0011]

[Chemical 3]

[0012]

[Chemical 4]

[0013]

[Chemical 5]

[0014]

[Chemical 6]

[0015]

[Chemical 7]

[0016]

[Chemical 8]

[0017]

[Chemical 9]

[0018]

[Chemical 10]

[0019]

[Chemical 11]

[0020]

[Chemical 12]

[0021]

[Chemical 13]

[0022]

[Chemical 14]

[0023]

[Chemical 15]

[0024]

[Chemical 16]

The compound of the present invention is synthesized by formylating benzocrown ether as a mother nucleus by Vilsmeier reaction,
Then, it is nitrated, the formyl group is oxidized with KMnO ₄ , and the resulting nitrobenzoic acid derivative is reduced with Fe to obtain an anthranilic acid derivative. The amino compound was diazotized, reacted with potassium xanthate, and then reduced with sodium hydrosulfite to obtain the desired compound 2 of the present invention. The benzocrown ether which is a mother nucleus is, for example, Synthesis 680 (1986), Tetrahedron Letters (Tetrahedron Lett.) 26 2705 (1985), Chemical Communication (Chem.commun) 268 (1986), Journal of Polymer. Science (J.PolymerSci.A-1) 9
817 (1971), Journal of American Chemical
Society (J. Amer. Chm. Soc.) 95 , 3842 (1973) Chemical Communication (Chem.commun) 414 (1975), 639 (19)
76), 640 (1976). In addition, the formylation of benzocrown ether is described in the Journal of
Chemical Society (JCS Dalton) p. 1696 (197)
8 years). The synthesis examples of representative compounds of the present invention are shown below.

Synthesis Example (Synthesis of Exemplified Compound 3) Journal of Chemical Society (JCS Dalton)
Benzo-1 synthesized by the method of page 1696 (1978)
10 g of 5-crown-5-4-aldehyde was dissolved in 70 ml of chloroform and the outside was cooled with a dry ice-methanol bath, and the fuming nitric acid (SG =
1.50) 10 ml was added dropwise. Then, the mixture was stirred at room temperature for 4 hours. The reaction solution was poured into water and extracted with chloroform. The chloroform layer was washed with water, dried and evaporated under reduced pressure to obtain 10 g of a crude nitro compound as a yellow solid. PMR (CDCl ₃ ) δ,
10.43 (1H, s, -CHO) 7.58 (1H,
s, 6th), 7.37 (1H, s, 3rd), 4.20-
4.29 (4H, m), 3.70-3.79 (8H,
m)

10 g of the crude nitro aldehyde compound was finely crushed and suspended in 7.8 ml of 35% NaOH,
Heat to an internal temperature of 70 ° C. 10 g of potassium permanganate was dissolved in 60 ml of water while stirring well, and the internal temperature was 73-80 ° C.
It was dripped at. (Time required 2 hours) After reacting at the same temperature for 4 hours,
The mixture was allowed to cool, the insoluble material was filtered off, and the filtrate was acidified with concentrated hydrochloric acid.
The precipitated crystals were collected by filtration, washed with water and dried. 7.9 g (yellow solid)
mp109-111 ° C PMR (DMSO) δ7.53
(1H, S) 7.26 (1H, S) 4.21-4.1
8 (4H, m) 3.79-3.73 (4H, m) 3.6
2- (8H, S) CMR (DMSO / NaOH) δ16
6.6, 151.5, 150.0, 141.9, 12
1.9, 121.8, 108.8, 70.4, 69.
4, 69.1, 68.1

Next, iron powder 15 g, water 15 ml, dioxane 3
2 ml of acetic acid was added to 0 ml of the mixture while heating and stirring, and 15 minutes later, the mixture was heated to reflux, and 7.1 g of crude nitro compound was added to 50 ml of dioxane.
Dissolve in ml and add dropwise. (Required time 10 minutes) After refluxing for 1 hour and allowing to cool, insoluble matter was filtered using Celite 520A. Dioxane was distilled off from the filtrate under reduced pressure to obtain 5.3 g of a crude amino compound.

5.2 g of this amino compound was added to 0.98 g of potassium hydroxide and 1.22 g of sodium nitrite together with 30 parts of water.
Dissolve it in ml and add it dropwise to a mixture of concentrated hydrochloric acid (12 ml) and water (16 ml) kept at an internal temperature of 0-5 ° C (time required: 20 minutes).
After stirring for 0 minutes, 4.4 g of potassium acetate was added to adjust the pH to 5 or less, and this diazonium salt was added dropwise to a solution of 7.28 g of potassium ethylxanthate dissolved in 30 ml of water at an internal temperature of 35 ° C. (required time). After stirring for 1 hour (room temperature), the mixture was acidified with concentrated hydrochloric acid, washed with water and dried. The crystals were dissolved in 50 ml of 10% sodium carbonate and refluxed, and 5.6 g of sodium hydrosulfite was added, and the mixture was refluxed for 1 hour. The reaction product was acidified with concentrated hydrochloric acid under cooling, the precipitated crystals were washed with water, dried and then separated by column chromatography with a mixed solution of chloroform: methanol = 1: 1. The desired fraction was concentrated to give pale yellow crystals. Yield 3.1g m
_{p240~242 ℃ PMR (DMSO-d 6} ) δ7.19 (1H, S)
7.61 (1H, S) 4.34 to 4.30 (4H, m)
4.04-3.95 (4H, m) 3.90-3.85
(8H, m) CMR (DMSO -d 6) δ170.
4, 157.9, 148.0, 133.3, 120.
4, 114.1, 99.5, 69.8, 68.6, 6
7.6, 66.4

The sensitizing dye used in the present invention is preferably a cyanine dye represented by the following chemical formulas 17, 18 and 19.

[0031]

[Chemical 17]

[0032]

[Chemical 18]

[0033]

[Chemical 19]

In the formula, R ³ and R ⁴ may be the same or different and each represents an alkyl group or a sulfoalkyl group, and R ⁵ represents a hydrogen atom, an alkyl group or an aryl group.
R ⁶ and R ⁷ may be the same or different and each represents an alkyl group or an aryl group. D is composed of 3 methylene groups to form a 6-membered ring. This 6-membered ring may be substituted with a lower alkyl group. E is composed of two methylene groups to form a 5-membered ring, and the 5-membered ring may be substituted with a lower alkyl group. Z ₁ or Z _{2 is} 5-
Or a 6-membered ring nitrogen-containing heterocyclic compound, for example, thiazole, benzothiazole, naphthothiazole, oxazole, benzoxazole, naphthoxazole, quinoline, benzoquinoline, benzimidazole, selenazole, benzoselenazole, indolenine, benzoindolenine, thiazoline, It forms an oxazoline ring and the like. X
^- is an anion, denotes chlorine anion, bromine anion, the tosylate anion. Also, n is 0, 1, 2, or 3.

The sensitizing dyes represented by Chemical formulas 17, 18 and 19 are well known compounds and are described in US Pat.
No. 457,078, No. 3,619,154, No. 3,6
82,630, 3,690,891, 3,69
No. 5,888, No. 4,030,932, No. 4,36
It can be synthesized by the method described in 7,800. Examples of the sensitizing dyes represented by Chemical formulas 17, 18 and 19 are shown below, but are not limited to these examples.

[0036]

[Chemical 20]

[0037]

[Chemical 21]

[0038]

[Chemical formula 22]

[0039]

[Chemical formula 23]

[0040]

[Chemical formula 24]

[0041]

[Chemical 25]

[0042]

[Chemical formula 26]

[0043]

[Chemical 27]

[0044]

[Chemical 28]

[0045]

[Chemical 29]

[0046]

[Chemical 30]

The amount of the cyanine dye added is usually an amount sufficient for spectral sensitization, that is, 10 ^-6 to 10 ^-10 mol per mol of silver halide.
^-3 mol range, particularly preferably 5 x 10 ^-6 to 1
It is in the range of × 10 ^-4 mol. Further, the addition of the sensitizing dye to the silver salt emulsion is usually carried out in a suitable solvent (eg water, methanol, DM
(F, N-methylpyrrolidone, etc.) and then added as a solution.

The supersensitizer of the present invention may be added before, after, or at the same time as the addition of the sensitizing dye, and the addition method is preferably a solution. The solvent used may be the same as that used for the sensitizing dye, but in the case of water, it is effective to add a small amount of caustic.

Supersensitizer 2 and sensitizing dye 1 of the present invention
When 7, 7, or 19 is used together, the molar ratio of the supersensitizer to the sensitizing dye is 40/1 to 1/10, preferably 5/1 to 1/5.

The silver halide in the photographic emulsion used in the method of the present invention may be any of silver chloride, silver bromide, silver chlorobromide, silver iodobromide, etc., but especially silver bromide or iodoodor. Silver iodide (particularly, silver iodide content of 10 mol% or less) is highly effective. The emulsion binder is gelatin, but part or all of it is replaced with natural polymers such as gelatin derivatives, albumin, agar, gum arabic, and alginic acid, or synthetic polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylamide. May be.

The silver halide emulsion used in the present invention may be coarse grains, fine grains or mixed grains thereof, and these can be prepared by a known method, single jet method or double jet method. Further, the crystal structure of the silver halide grains may be uniform even in the inside, or may have a so-called layered structure in which the inside and the outside are different. It may be of the surface or internal latent image type. These are James' The theory of photog
raphic process "(MacMillan), Glafkides" Phot
It can be prepared by a generally accepted method such as an ammonia method, a neutral method, an acidic method or the like, which is also described in the books such as “graphic chemistry” (Fountain Press).

The average diameter of the silver halide grains is not particularly limited, but 0.04 μm to 2 μm is particularly preferable. The particle size distribution may be narrow or wide. The silver halide emulsion may or may not be physically ripened. The silver halide emulsion may or may not be chemically sensitized. As the method of chemical sensitization, those described in the above-mentioned publications can be used. An antifoggant such as tetraazaindene may be added to the photographic emulsion spectrally sensitized by the method of the present invention for storage stability. Further, the film can be hardened with a commonly used hardener.

In the photographic emulsion sensitized by the present invention, a surfactant such as anionic or nonionic surfactant can be used as a coating aid or for the purpose of preventing static charge. The support on which the emulsion is coated may be paper, film, glass plate, metal plate, or the like. Hereinafter, the present invention will be described in detail with reference to examples.

[0054]

Example 1 Using a double jet method, the average particle size was 0.7 μm.
A cubic AgBr emulsion of was prepared. That is, AgNO ₃ and KBr aqueous solution were simultaneously added while the gelatin aqueous solution was well stirred and pAg was kept constant. This emulsion contains 0.38 mol AgBr / Kg and about 45 g gelatin. From the emulsion thus prepared, 2 kg was sampled, and 1% by weight of sodium thiosulfate (5
6.7 ml of water salt) was added, and the mixture was aged at a temperature of 50 ° C. for 1 hour.
Further, divide the emulsion into 100 g portions, and add 0.1% of the sensitizing dye.
Methanol solution and 5 ml of 10 ^-2 mol / l methanol solution of supersensitizer were added, and each of them was dried on a cellulose acetate film provided with a gelatin subbing layer to give a film thickness of about 4 μm. Coating was carried out to prepare a photographic light-sensitive material.

Each sample was exposed with a tungsten bulb (color temperature 2854 ° K) for 10 seconds through a continuous wedge and a color filter. The color filter is a blue filter (Fuji Photo Film BPN-45),
I used a yellow filter (minus blue, Toshiba glass filter). After exposure, 2 with methol and ascorbic acid developer
It was developed at 0 ° C. for 10 minutes. The composition of the developer is as follows.

Metol 2.5 g Ascorbic acid 10 g KBr 1.0 g Nabox 35.0 g Water was added to make 1 l (pH 9.8).

The photographic speed is represented by the reciprocal of the exposure amount required to give a photographic density of fog + 0.1. Blue sensitivity and minus blue sensitivity are the relative sensitivities obtained using the above filters, respectively. Addition amount is mmol / A
gBr mol.

[0058]

[Table 1]

[0059]

[Table 2]

[0060]

[Table 3]

As is clear from the sensitivity values in Tables 1 to 3,
The supersensitizer of the present invention alone increases the intrinsic sensitivity (blue sensitivity), but when it is used in combination with the sensitizing dye, the intrinsic sensitivity and spectral sensitivity are further increased.

Example 2 An emulsion comprising octahedral silver bromide grains having an average grain size of 0.7 μm was prepared and sulfur-sensitized in the same manner as in Example 1. This was similarly exposed and developed to prepare Tables 4 and 5.

[0063]

[Table 4]

[0064]

[Table 5]

Example 3 The amount of dye was fixed at 0.24 mmol / mol AgBr and the amount of the supersensitizer was fixed at 1.3 molmol / mol AgBr, and evaluation was conducted in the same manner to prepare Table 6.

[0066]

[Table 6]

[0067]

[Chemical 31]

[0068]

[Chemical 32]

Example 4 An average particle size of 0.3 μm was obtained using a conventional double-mix method.
A cubic silver chloride emulsion was prepared. That is, the aqueous solution of silver nitrate and the aqueous solution of potassium chloride were simultaneously added while the aqueous gelatin solution was well stirred. This emulsion is 0.29 / Kg
It contains moles of silver chloride and about 45 g of gelatin. 2 Kg of the emulsion thus obtained was added to 1% of 0.1% sodium thiosulfate.
3.3 ml was added, and sulfur sensitization was performed at 50 ° C. for 1 hour. Further, the emulsion was divided into 50 g each, and 2 ml of a 0.1% dye-methanol solution was added, and further 10 ^-2 ml / l of a supersensitizer methanol solution was added, and these were each provided with a gelatin undercoat layer. It was coated on the film so that the film thickness would be 4 μ after drying. The exposure and development were the same as in Example 1.

[0070]

[Table 7]

Example 5 Cubic silver iodobromide (silver iodide 1 mol%) having an average particle size of 0.6 μ was prepared. Sulfur sensitization was performed in the same manner as in Example 1. This photosensitive material was exposed and developed in the same manner as in Example 1.

[0072]

[Table 8]

[0073]

By using the supersensitizer of the present invention together with a sensitizing dye, supersensitization occurs and the spectral sensitivity can be effectively increased.

Claims (1)

[Claims] 1. A silver halide photographic emulsion comprising a compound of the following chemical formula 1. [Chemical 1] (In the formula, Z is a hydrogen atom, a metal ion, or an acyl group,
R ¹ and R ² may be the same or different and each represents a hydrogen atom, an alkyl group or an alkoxy group, X is a divalent linking group and forms a 15, 18 or 21 membered ring. )