Process for the preparation of metallocene compounds

A process for the preparation of cyclopentadienyl metallocene compounds of formula (I):

• (Cp)(ZR1m)n(A)rMLpL′q (I)
• wherein (ZR1m)n is a divalent group bridging Cp and A, Z being C, Si, Ge, N or P, and the R1 groups, same or different from each other, being hydrogen or linear or branched, saturated or unsaturated C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl or C7-C20 arylalkyl groups;
• Cp is a substituted or unsubstituted cyclopentadienyl group, optionally condensed to one or more substituted or unsubstituted, saturated, unsaturated or aromatic rings, containing from 4 to 6 carbon atoms, optionally containing one or more heteroatoms;
• A is —O—, —S—, —N(R2)—, wherein R2 is hydrogen, a linear or branched, saturated or unsaturated C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl or C7-C20 arylalkyl, or A has the same meaning of Cp;
• M is a transition metal belonging to group 3, 4, 5, 6 or to the lanthanide or actinide groups of the Periodic Table of the Elements (IUPAC version);
• the substituents L, same or different from each other, are monoanionic sigma ligands selected from the group consisting of linear or branched, saturated or unsaturated C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl and C7-C20 arylalkyl groups, optionally containing one or more Si or Ge atoms;
• the substituents L′, same or different from each other, are halogens or —OR5, wherein R5 has the same meaning of R1;
• m is 1 or 2;
• n ranges from 0 to 4;
• r is 0 or 1;
• n is 0 when r is 0;
• p ranges from 1 to 3;
• q ranges from 0 to 2, p+q being equal to the oxidation state of the metal M minus 2 when r=1, and minus 1 when r=0, and p+q being≦4;
• said process being characterized by comprising the following steps:
• (1) reacting a ligand of formula (Y—Cp)(ZR1m)n(A—Y)r with at least (1+r+p) molar equivalents of a compound of formula LjB or LMgL′, wherein Cp, A, Z, R1, m, n, p, r, L and L′ have the meaning reported above;
• the groups Y, the same or different from each other, are suitable leaving groups;
• B is an alkaline or alkaline-earth metal;
• and j is 1 or 2, j being equal to 1 when B is an alkaline metal, and j being equal to 2 when B is an alkaline-earth metal;
• and
• (2) reacting the product obtained from step (1) with at least 1 molar equivalent of a compound of formula ML′s, wherein M and L′ have the meaning reported above;
• s is an integer corresponding to the oxidation state of the metal and ranges from 3 to 6.