ansa-metallocene derivatives XXXIX biphenyl-bridged metallocene complexes of titanium, zirconium, and vanadium: Syntheses, crystal structures and enantioseparation

Abstract

Chiral, biphenyl-bridged metallocene complexes of general type biph(3,4-R2CsH2)2MCI2 (biph = 1,1'-biphenyldiyI) were synthesized and characterized. For the dimethyl-substituted titanocenes and zirconocenes (R CH 3 ; M Ti, Zr). preparations with increafed overall yields and an optical resolution method were developed. The bis(2-tetrahydroindenyI) complexes (R,R = (CH 2)4; M = Ti, Zr) were obtained by an alternative synthetic route and characterized with regard to their crystal structures. Syntheses of the phenyl-substituted derivatives (R C 6 H 5; M Ti, Zr) and of a chiral, methyl-substituted vanadocene complex (R CH 3; M V) are also reported.

Towards a Library of “Early‐Late” Ti–Ru Bimetallic Complexes

“…According to well-known procedures for the resolution of titanium metallocenes, [14][15][16][17][18] we carried out the reaction of one equivalent of sodium bi- Scheme 1. naphtholate with 1 in THF at room temperature to afford the desired titanocene binaphtholate phosphane 7. However, a careful study of the 1 H NMR spectrum of the crude product revealed that a partial loss of the Cp(CH 2 ) 2 PPh 2 moiety occurs in this reaction.…”

Ansa-vanadocene complexes with short interannular bridges

“…This method was previously successfully used for preparation of tetramethylethano- [21] and biphenyl-bridged vanadocene dichlorides [22].…”

“…Previously some efficient routes for preparation of ansavanadocene complexes were developed by Brintzinger et al [20][21][22]. Such studies were focused particularly on the catalytic properties of ansa-metallocenes toward polymerization of a-olefins.…”

Enantioselective Hydrogenations with Chiral Titanocenes

“…Consecutive addition of chiral and non-chiral cyclopentadienyl anions to the titanium chloride results in asymmetric titanocenes with two different ligands. Separation of the enantiomers can be carried out by selective crystallization of the free isomeric compounds, or by complexation with optically pure compounds [21]. …”