申请人:EASTMAN KODAK COMPANY
公开号:EP1220024A2
公开(公告)日:2002-07-03
This invention provides a photographic element comprising at least one silver halide emulsion layer in which the silver halide is sensitized with a compound of the formula (a):
Δ-(t)m-XY' (a)
XY'-(t)m -Δ (b)
Δ-(t)m-XY'-(t)m-Δ (c)
wherein Δ is protective group that is eliminated during development of the photographic element, t is a timing group, m is an integer from 0 to 3, and XY' is a fragmentable electron donor moiety in which X is an electron donor group and Y' is a leaving proton H or a leaving group Y, with the proviso that if Y' is a proton, a base, β-, is present in the emulsion or is covalently linked directly or indirectly to X, and wherein:
1) X-Y' has an oxidation potential between 0 and about 1.4 V;
2) the oxidized form of X-Y' undergoes a bond cleavage reaction to give the radical X• and the leaving fragment Y'; and
3) the radical X• has an oxidation potential <-0.7V.
本发明提供了一种感光元件,它包含至少一个卤化银乳剂层,其中的卤化银是用式(a)化合物感光的:
Δ-(t)m-XY' (a)
XY'-(t)m -Δ (b)
Δ-(t)m-XY'-(t)m-Δ (c)
其中,Δ 是在感光元件显影过程中消除的保护基团,t 是定时基团,m 是 0 至 3 的整数,XY'是可破碎的电子供体分子,其中 X 是电子供体基团,Y'是离去质子 H 或离去基团 Y,但如果 Y'是质子,则在乳剂中存在碱 β-,或直接或间接地与 X 共价连接,并且其中:
1) X-Y' 的氧化电位在 0 至约 1.4 V 之间;
2) X-Y'的氧化形式发生键裂反应,生成自由基 X- 和离去片段 Y';以及
3) 自由基 X- 的氧化电位<-0.7V。