There is provided a compound of Formula I
wherein X, Y and Z are each independently of each other an optional linker group; R
1
is a ring system; R
2
is selected from hydrocarbyl groups, oxyhydrocarbyl groups, cyano (—CN), nitro (—NO
2
) and halogens; R
3
and R
4
are independently selected from H and hydrocarbyl, ring A and B are independently optionally further substituted.
提供一种公式为I的化合物,其中X、Y和Z各自独立地为可选的连接基团;R1是一个环系;R2选择自烃基团、
氧烃基团、
氰基(—CN)、硝基(—
NO2)和卤素;R3和R4独立地选择自H和烃基团,环A和B独立地可选地进一步取代。