title: Highly strained heterometallacycles of Group 4 metallocenes with bis(diphenylphosphino)methanide ligands.
abstract: A study of the coordination chemistry of different bis(diphenylphosphino)methanide ligands [Ph2PC(X)PPh2] (X = H, SiMe3) with Group 4 metallocenes is presented. The paramagnetic complexes [Cp2Ti{κ(2)-P,P-Ph2PC(X)PPh2}] (X = H (3 a), X = SiMe3 (3 b)) have been prepared by the reactions of [(Cp2TiCl)2] with [Li{C(X)PPh2}2(thf)3]. Complex 3 b could also be synthesized by reaction of the known titanocene alkyne complex [Cp2Ti(η(2)-Me3SiC2SiMe3)] with Ph2PC(H)(SiMe3)PPh2 (2 b). The heterometallacyclic complex [Cp2Zr(H){κ(2)-P,P-Ph2PC(H)PPh2}] (4 aH) has been prepared by reaction of the Schwartz reagent with [Li{C(H)PPh2}2(thf)3]. Reactions of [Cp2HfCl2] with [Li{C(X)PPh2}2(thf)3] gave the highly strained corresponding metallacycles [Cp2M(Cl){κ(2)-P,P-Ph2PC(X)PPh2}] (5 aCl and 5 bCl) in very good yields. Complexes 3 a, 4 aH, and 5 aCl have been characterized by X-ray crystallography. Complex 3 a has also been characterized by EPR spectroscopy. The structure and bonding of the complexes has been investigated by DFT analysis. Reactions of complexes 4 aH, 5 aCl, and 5 bCl did not give the corresponding more unsaturated heterometallacyclobuta-2,3-dienes.
authors.affiliation: Leibniz-Institut für Katalyse e. V. an der Universität Rostock, Albert-Einstein-Strasse 29 A, 18059 Rostock, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Haehnel
authors.forename: Sven
authors.initials: S
authors.lastname: Hansen
authors.forename: Jacqueline B
authors.initials: JB
authors.lastname: Priebe
authors.forename: Anke
authors.initials: A
authors.lastname: Spannenberg
authors.forename: Perdita
authors.initials: P
authors.lastname: Arndt
authors.forename: Angelika
authors.initials: A
authors.lastname: Brückner
authors.forename: Uwe
authors.initials: U
authors.lastname: Rosenthal