TY - JOUR
T1 - Axially asymmetric metal alkyls. Part 5. Synthesis and reduction to ZrIII species of group 4 metallepines [ML(η-C5H5)2] [L = (2-CHRC6H4)22-, R = H, M = Ti, Zr, or Hf)], isomers of [ZrL(η-C5H5)2] (R = SiMe3), and...
T2 - ... meso-[M{1,8-(CHSiMe3)2C10H6}(η-C5H5)2](M = Zr or Hf); X-ray crystal structures of [TiL(η-C5H5)2](R = H) and λ- and δ-RS-[ZrL(η-C5H5)2](R = SiMe3)
AU - Engelhardt, Lutz M.
AU - Leung, Wing Por
AU - Papasergio, Rocco I.
AU - Raston, Colin L.
AU - Twiss, Paul
AU - White, Allan H.
PY - 1987/10
Y1 - 1987/10
N2 - Treating [MCl2(η-C5H4R′)2] with a di-Grignard reagent and/or a dilithium reagent based on (2-CHRC6H4)22–(L) yields the metallacycles [ML(η-C5H4R′)2](R = R′= H, M = Ti, Zr, or Hf; R = H, R′= SiMe3, M = Zr)(5), and a mixture of diastereoisomers of λ-RS- and δ-RS-[ZrL(η-C5H5)2](R = SiMe3)(6a), and λ-RR-and δ-SS-[ZrL(η-C5H5)2](R = SiMe3)(6b). Compound (6a) was readily converted to (6b) by photolysis in hexane. The ‘strained’ metallacycles meso-[M{1,8-(CHSiMe3)2C10H6}(η-C5H5)2](M = Zr or Hf)(7) were prepared from an intrinsically unstable dilithium reagent. Reduction of (5),(6a) and (6b), and (7) chemically and electrochemically shows that the generated d1 species are stable at ca. 20 °C except for M = Hf, and that for (5)[and possibly (6a) and (6b)] reduction is associated with metal–carbon bond rupture. The structures of (5)(M = Ti) and (6a) have been established from single-crystal X-ray diffraction data [Ti–Cα 2.207Å, Cα–Ti–Cα 87·8°, dihedral angle between phenyl groups, φ 62.2°; Zr–Cα 2.338Å, Cα–Zr–Cα 98.3(2)°, φ 73.6°].
AB - Treating [MCl2(η-C5H4R′)2] with a di-Grignard reagent and/or a dilithium reagent based on (2-CHRC6H4)22–(L) yields the metallacycles [ML(η-C5H4R′)2](R = R′= H, M = Ti, Zr, or Hf; R = H, R′= SiMe3, M = Zr)(5), and a mixture of diastereoisomers of λ-RS- and δ-RS-[ZrL(η-C5H5)2](R = SiMe3)(6a), and λ-RR-and δ-SS-[ZrL(η-C5H5)2](R = SiMe3)(6b). Compound (6a) was readily converted to (6b) by photolysis in hexane. The ‘strained’ metallacycles meso-[M{1,8-(CHSiMe3)2C10H6}(η-C5H5)2](M = Zr or Hf)(7) were prepared from an intrinsically unstable dilithium reagent. Reduction of (5),(6a) and (6b), and (7) chemically and electrochemically shows that the generated d1 species are stable at ca. 20 °C except for M = Hf, and that for (5)[and possibly (6a) and (6b)] reduction is associated with metal–carbon bond rupture. The structures of (5)(M = Ti) and (6a) have been established from single-crystal X-ray diffraction data [Ti–Cα 2.207Å, Cα–Ti–Cα 87·8°, dihedral angle between phenyl groups, φ 62.2°; Zr–Cα 2.338Å, Cα–Zr–Cα 98.3(2)°, φ 73.6°].
UR - http://www.scopus.com/inward/record.url?scp=51149216609&partnerID=8YFLogxK
U2 - 10.1039/DT9870002347
DO - 10.1039/DT9870002347
M3 - Article
SP - 2347
EP - 2357
JO - Journal of the Chemical Society, Dalton Transactions
JF - Journal of the Chemical Society, Dalton Transactions
SN - 1470-479X
IS - 10
ER -