Highly Strained Heterometallacycles of Group4 Metallocenes with Bis(diphenylphosphino)methanide Ligands

• Published in: Chemistry : a European journal 2013-06, Vol.19 (23), p.7568-7574
• Main Authors: Haehnel, Martin, Hansen, Sven, Priebe, Jacqueline B, Spannenberg, Anke, Arndt, Perdita, Brückner, Angelika, Rosenthal, Uwe
• Format: Article
• Language: English
• Subjects: Alkynes; Aromaticity; Bonding; Chemistry; Ligands; Metallocenes; Metalorganic compounds; Stabilization; X-rays
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201300218

A study of the coordination chemistry of different bis(diphenylphosphino)methanide ligands [Ph2PC(X)PPh2] (X=H, SiMe3) with Group4 metallocenes is presented. The paramagnetic complexes [Cp2Ti{[kappa]2-P,P-Ph2PC(X)PPh2}] (X=H (3a), X=SiMe3 (3b)) have been prepared by the reactions of [(Cp2TiCl)2] with [Li{C(X)PPh2}2(thf)3]. Complex 3b could also be synthesized by reaction of the known titanocene alkyne complex [Cp2Ti(η2-Me3SiC2SiMe3)] with Ph2PC(H)(SiMe3)PPh2 (2b). The heterometallacyclic complex [Cp2Zr(H){[kappa]2-P,P-Ph2PC(H)PPh2}] (4aH) 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){[kappa]2-P,P-Ph2PC(X)PPh2}] (5aCl and 5bCl) in very good yields. Complexes 3a, 4aH, and 5aCl have been characterized by X-ray crystallography. Complex 3a has also been characterized by EPR spectroscopy. The structure and bonding of the complexes has been investigated by DFT analysis. Reactions of complexes 4aH, 5aCl, and 5bCl did not give the corresponding more unsaturated heterometallacyclobuta-2,3-dienes. [PUBLICATION ABSTRACT]