Borata-Alkene Derived Syntheses of (F₅C₆)₂B-Substituted Bis(indenyl) Group 4 Metal Complexes

Abstract

An indene based borata-alkene was used as a reagent for the synthesis of B­(C6F5)2-functionalized group 4 bent-metallocene complexes. The respective borata-alkene was prepared by HB­(C6F5)2 hydroboration of dimethylbenzofulvene followed by deprotonation with lithium tetramethylpiperidide. Treatment of CpTiCl3 or CpZrCl3 with the borata-alkene gave the respective [(C6F5)2B-indenyl]­CpMCl2 bent-metallocene complexes. Both were characterized by X-ray diffraction. The boryl-functionalized metallocenes gave active ethene or propene polymerization catalysts, respectively, upon activation with triethylaluminum.

The BC bond: some recent developments

“…In this case, η 5 -indenyl coordination to zirconium was favoured to give the boryl-functionalized bent metallocene complex 23 . 15 In the presence of AlEt 3 complex 23 gave an active ethylene and propene polymerization catalyst.…”

Borata‐Alkene Species as Nucleophilic Reservoir

“…[51] Erker and co‐workers also observed that indene based borata‐alkene species 4 could be used as ligand to react with CpZrCl 3 towards the formation of bent‐metallocene complex [(C 6 F 5 ) 2 B‐indenyl]CpZrCl 2 ( 36 ) (Figure 5). [52a] Characterization by X‐ray diffraction and NMR concluded that a short B−C bond length (1.505(4) Å) is present in the complex indicating some slight residual borata fulvene character in the structure of the bent‐metallocene complex 36 . The same authors have described the synthesis and complete characterization by X‐ray diffraction of a rhodium complex 37 containing a P/C=B chelate ligand, in a distorted square‐planar coordination geometry at rhodium (Figure 5).…”