is halogen or r 4 is chloroacetyl c 1 4 alkyl substituted or unsubstituted c 6 10 aryl or substituted or unsubstituted heteroaryl b if r 12 and r 13 together form a chemical bond and r 11 is hydrogen and r 9 and r 10 together form a chemical bond then r 4 r 5 r 6 r 7 r 8 x and y are as defined in item a and c if r 10 and r 11 and r 12 and r 13 together form a chemical bond then y is a stripped oxygen or sulfur and if r 7 r 8 and r 9 stand for an unshared electron pair then a positive cation forms a salt with the thus formed anion or r 7 is hydrogen c 1 4 alkyl substituted or unsubstituted c 6 10 aryl x r 5 r 6 r 7 is halogen or x represents a stripped oxygen or sulfur atom and if r 4 r 5 and r 6 stand for a lone electron pair then a positive cation forms a salt with the thus formed anion or r 5 and r 6 stand for an unshared electron pair or x is a stripped nitrogen atom and r 4 is chloroacetyl c 1 4 alkyl substituted or unsubstituted c 6 10 aryl or substituted heteroaryl if y and x are stripped oxygen or sulfur and r 5.