| abstract |
Imidio-s-heptazine derivatives represented by the formula (1): wherein R a , R b and R c independently with the provisos that at least one radical of R a , R b and R c is an imido radical, the radicals -NH 2 and -Cl are not jointly contained and that the radicals R 1 and R 2 in the imido radical is independent alkyl radicals, aryl radicals, phthal radicals, Tetrafluorphthalreste, Pyromellitreste are |