Abstract: The present invention relates to compounds of the general formula (I) wherein Z corresponds a to — a C1-C22-alkyl radical substituted by halogen, phosphonic acid or phosphonic acid ester groups —P(O)(OR1)2 (wherein the radicals R1 can be identical or different and correspond to a hydrogen atom or C1-C12-alkyl), sulphonic acid groups —SO3H, halosilyl radicals —SiHalnR23?n(R2?C1-C18-alkyl, n=an integer from 1 to 3), thiol groups or trialkoxysilyl radicals —Si(OR3)3 (R3?C1-C18-alkyl), — a C5-C12-cycloalkyl radical substituted by halogen, phosphonic acid or phosphonic acid ester groups—P(O) (OR1)2 (wherein the radicals R1 can be identical or different and correspond to a hydrogen atom or C1-C12-alkyl), sulphonic acid groups —SO3H, halosilyl radicals —SiHal?nR23?n(R2?C1-C18-alkyl, n=an integer from 1 to 3), thiol groups or trialkoxysilyl radicals —Si(OR3)3 (R3?C1-C18-alkyl), — a C6-C14-aryl radical or heteroaryl radical from the group of the thienyl, pyrryl, furyl or pyridyl radicals substituted by halogen, phosph