Patent ID: 7002031

Claim:
A process for preparing silicon-bridged metallocene compounds of formula (I): (Cp)(SiR 1 2 )(Cp)ML q (I) wherein (SiR 1 2 ) is a divalent group bridging the two Cp rings, the R 1 groups, equal to or different from each other, are hydrogen atoms, or linear or branched, saturated or unsaturated C 1 –C 20 alkyl, C 3 –C 20 cycloalkyl, C 6 –C 20 aryl, C 7 –C 20 alkylaryl or C 7 –C 20 arylalkyl groups, two R 1 can optionally join to form a 3–7 membered ring; Cp, equal to or different from each other, 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; 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, equal to or different from each other, are monoanionic sigma ligands selected from the group consisting of linear or branched, saturated or unsaturated C 1 –C 20 alkyl, C 3 –C 20 cycloalkyl, C 6 –C 20 aryl, C 7 –C 20 alkylaryl and C 7 –C 20 arylalkyl groups, optionally containing one or more Si or Ge atoms; q is an integer ranging from 0 to 2, being equal to the oxidation state of the metal M minus 2; said process comprises the following steps: a) reacting, at a temperature of between −10° C. and 70° C., a ligand of formula (Y-Cp)(SiR 1 2 )(Cp-Y) with about 2 molar equivalents of an alkylating agent of formula TH w , L j B or LMgL′, wherein T is lithium, sodium or potassium, H is an hydrogen atom, w is 0 or 1, when w is 0 the compound TH w is metallic lithium, sodium or potassium, when w is 1 the compound of formula TH w is an hydride of lithium, sodium or potassium; L′ is an halogen atom selected from chlorine, bromine and iodine; B is an alkali or alkali-earth metal; and j is 1 or 2, j being equal to 1 when B is an alkali metal, and j being equal to 2 when B is an alkali-earth metal; the groups Y, the same or different from each other, are suitable leaving groups; b) after the reaction has been completed, adding at least q molar equivalents of an alkylating agent of formula L j B or LMgL′; and c) reacting, at a temperature of between −10° C. and 70° C., the product obtained from step b) with at least 1 molar equivalent of a compound of formula ML′ s , wherein s is an integer corresponding to the oxidation state of the metal and ranges from 3 to 6; and L′ is an halogen atom selected from chlorine, bromine and iodine.