Dihalogenated ferrocenes and processes for the preparation thereof

A compound of formula VI ##STR32## R.sub.1 is C.sub.1 -C.sub.8 alkyl, phenyl or phenyl substituted by from 1 to 3 C.sub.1 -C.sub.4 alkoxy substituents;

• R.sub.10 and R.sub.11 are identical or different and are C.sub.1 -C.sub.12 alkyl, C.sub.5 -C.sub.12 cycloalkyl, phenyl, C.sub.5 -C.sub.12 cycloalkyl substituted by C.sub.1 -C.sub.4 alkyl or by C.sub.1 -C.sub.4 alkoxy, or phenyl substituted by from one to three C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, --SiR.sub.4 R.sub.5 R.sub.6, halogen, --SO.sub.3 M, --CO.sub.2 M, --PO.sub.3 M,--NR.sub.7 R.sub.8, --(.sup.+ NR.sub.7 R.sub.8 R.sub.9)X.sup.- or C.sub.1 -C.sub.5 fluoroalkyl substituents;
• Hal is F, Cl, Br or I;
• and
• R.sub.12 and R.sub.13 are each independently of the other C.sub.1 -C.sub.12 alkyl, C.sub.5 -C.sub.12 cycloalkyl, phenyl, C.sub.5 -C.sub.12 cycloalkyl substituted by C.sub.1 -C.sub.4 alkyl or by C.sub.1 -C.sub.4 alkoxy, or phenyl mono- or poly-substituted by from one to three C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, --SiR.sub.4 R.sub.5 R.sub.6, halogen, --SO.sub.3 M, --CO.sub.2 M, --PO.sub.3 M, --NR.sub.7 R.sub.8, --(.sup.+ NR.sub.7 R.sub.8 R.sub.9)X.sup.- or C.sub.1 -C.sub.5 fluoroalkyl substituents;
• or the group --PR.sub.12 R.sub.13 is a radical of formula IV, IVa, IVb or IVc ##STR33## R.sub.4, R.sub.5 and R.sub.6 are each independently of the others C.sub.1 -C.sub.12 alkyl or phenyl;
• R.sub.7 and R.sub.8 are H, C.sub.1 -C.sub.12 alkyl or phenyl or R.sub.7 and R.sub.8 together are tetramethylene, pentamethylene or 3-oxa-1,5-pentylene;
• R.sub.9 is H or C.sub.1 -C.sub.4 alkyl;
• M is H or an alkali metal;
• X.sup.- is the anion of a monobasic acid.