prov:value
| - R3 and R4 are identical or different and are a hydrogen atom, a halogen atom, a C1 -C10 -alkyl group, which may be halogenated, a C6 -C10 -aryl group, an --NR2 15, --SR15, --OSiR3 15, --SiR3 15 or --PR2 15 radical in which R15 is a halogen atom, a C1 -C10 -alkyl group or a C6 -C10 -aryl group,
|