Preparation of transition-metal-alkyl-complexes carrying a bidentate, dianionic ligand

A process for the preparation of organometallic complexes of formula (I):

• (A)(ZR1m)n(A′)MLpL′q (I)
• wherein (ZR1m)n is a C1-C50 divalent group bridging A and A′, Z being C, Si, Ge, N, P, O or S;
• the R1 groups, the same or different from each other, are selected from the group consisting of hydrogen, linear or branched, saturated or unsaturated C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl and C7-C20 arylalkyl groups, two or more R1 groups optionally forming together one or more saturated, unsaturated or aromatic rings;
• m is 0, 1 or 2;
• n is an integer ranging from 1 to 8;
• A and A′, the same or different from each other, are divalent anionic groups selected from —O—, —S— and —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, optionally containing one or more atoms belonging to Groups 13-17 of the Periodic Table;
• 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;
• the substituents L, the 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′, the same or different from each other, are halogens or —OR3, wherein R3 is selected from the group consisting of hydrogen, linear or branched, saturated or unsaturated C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl and C7-C20 arylalkyl groups;
• p is an integer ranging from 1 to 3;
• q is an integer ranging from 0 to 2, p+q being equal to the oxidation state of the metal M minus 2, and p+q being ≦3;
• said process comprising the following steps:
• (1) reacting a ligand of formula (H—A)(ZR1m)(A′—H) with about (2+p) molar equivalents of a compound of formula LjB or LMgL′, wherein A, A′, Z, R1, m, n, p, L and L′ have the meaning reported above;
• 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 about 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.