A compound of the formula or (I*) in which X is NR, S, O or PR; R is aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl; A is -NR 6 R 7, -P R 8 R 9, -PR 10 R 11, -S 2 R 12, -S R 13, -SR 14 or -OR 15; R 1, R 2, R 3 are each independently aryl, heteroaryl, alkyl, cycloalkyl, heterocycloalkyl, a crosslinkable or polymerizable group attached via a spacer, where at least one of the R 1, R 2, R 3 radicals comprises at least two carbon atoms, or OR 22, R 4, R 5 are each independently alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, a crosslinkable or polymerizable group attached via a spacer, an A group or a group with donor or acceptor action; n, m are each independently 0, 1, 2, 3; R 6, R 7 together with the nitrogen atom form a cyclic radical which has 3 to 10 ring atoms, which may be unsubstituted or substituted by one or more substituents selected from alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl and a group with donor or acceptor action, and/or may be fused to one or more further cyclic radicals having 3 to 10 ring atoms, where the fused radicals may be unsubstituted or substituted by one or more substituents selected from alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, a crosslinkable or polymerizable group attached via a spacer, and a group with donor or acceptor action; R 22 is independently SiR 23 R 24 R 25, aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl, a crosslinkable or polymerizable group attached via a spacer, optionally substituted by an OR 28 group, R 28 is independently SiR 23 R 24 R 25, aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl, a crosslinkable or polymerizable group attached via a spacer, R 8, R 9, R 10, R 11, R 12, R 13, R 14, R 15, R 23, R 24, R 25 are each independently aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl, a crosslinkable or polymerizable group attached via a spacer, or two units of the general formula and/or (I*) are bridged to one another via a linear or branched, saturated or unsaturated bridge optionally interrupted by at least one heteroatom or via O, where this bridge in the general formula and/or (I*) is in each case attached to the silicon atoms instead of R 2. X is NR, S, O or PR; R is aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl; A is -NR 6 R 7, -P R 8 R 9, -PR 10 R 11, -S 2 R 12, -S R 13, -SR 14 or -OR 15; R 1, R 2, R 3 are each independently aryl, heteroaryl, alkyl, cycloalkyl, heterocycloalkyl, a crosslinkable or polymerizable group attached via a spacer, where at least one of the R 1, R 2, R 3 radicals comprises at least two carbon atoms, or OR 22, R 4, R 5 are each independently alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, a crosslinkable or polymerizable group attached via a spacer, an A group or a group with donor or acceptor action; n, m are each independently 0, 1, 2, 3; R 6, R 7 together with the nitrogen atom form a cyclic radical which has 3 to 10 ring atoms, which may be unsubstituted or substituted by one or more substituents selected from alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl and a group with donor or acceptor action, and/or may be fused to one or more further cyclic radicals having 3 to 10 ring atoms, where the fused radicals may be unsubstituted or substituted by one or more substituents selected from alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, a crosslinkable or polymerizable group attached via a spacer, and a group with donor or acceptor action; R 22 is independently SiR 23 R 24 R 25, aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl, a crosslinkable or polymerizable group attached via a spacer, optionally substituted by an OR 28 group, R 28 is independently SiR 23 R 24 R 25, aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl, a crosslinkable or polymerizable group attached via a spacer, R 8, R 9, R 10, R 11, R 12, R 13, R 14, R 15, R 23, R 24, R 25 are each independently aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl, a crosslinkable or polymerizable group attached via a spacer,