Patent ID: 6933400

Claim:
A complex having one of the formulae I a to d, where the variables are defined as follows: M is an element of groups 6 to 10 of the Periodic Table of the Elements in the oxidation state +2 to +4; Nu is selected from the group consisting of O, S and N—R 7 ; R 1 to R 7 to are selected from among hydrogen, C 1 -C 18 -alkyl, substituted or unsubstituted, C 2 -C 18 -alkenyl, substituted or unsubstituted, having from one to 4 isolated or conjugated double bonds; C 3 -C 12 -cycloalkyl, substituted or unsubstituted, C 7 -C 13 -aralkyl, C 6 -C 14 -aryl, unsubstituted or substituted by one or more identical or different substituents selected from the group consisting of C 1 -C 8 -alkyl, substituted or unsubstituted, C 3 -C 12 -cycloalkyl, C 7 -C 13 -aralkyl, C 6 -C 14 -aryl, halogen, C 1 -C 6 -alkoxy, substituted or unsubstituted, C 6 -C 14 -aryloxy, SiR 8 R 9 R 10 and O—SiR 8 R 9 R 10 ; five- and six-membered nitrogen-containing heteroaryl radicals, unsubstituted or substituted by one or more identical or different substituents selected from the group consisting of C 1 -C 8 -alkyl, substituted or unsubstituted, C 3 -C 12 -cycloalkyl, C 7 -C 13 -aralkyl, C 6 -C 14 -aryl, halogen, C 1 -C 6 -alkoxy, C 6 -C 14 -aryloxy, SiR 8 R 9 R 10 and O—SiR 8 R 9 R 10 ; where adjacent radicals R 1 to R 7 may be joined to one another to form a 5- to 12-membered non-aromatic ring; L 1 is an uncharged, organic or inorganic ligand, L 2 is an organic or inorganic anionic ligand, where L 1 and L 2 may be joined to one another by one or more covalent bonds, z is an integer from 1 to 3, R 8 to R 10 are identical or different and are selected from the group consisting of hydrogen, C 1 -C 8 -alkyl, C 3 -C 12 -cycloalkyl, C 7 -C 13 -aralkyl and C 6 -C 14 -aryl.