Bridged Dinuclear Tripodal Tris(amido)phosphane Complexes of Titanium and Zirconium as Diligating Building Blocks for Organometallic Polymers

Abstract

AbstractAppropriate bridging ligands allow for the preparation of bimetallic titanium and zirconium precursors to transition‐metal‐containing polymers using the formally trianionic P(CH2NArR)3 ligand (where ArR = Ph, and 3,5‐Me2C6H3 for a and b, respectively). Lithiation of the known amidophosphane ligand precursors P(CH2NHArR)3 (1a,b) with 3 equiv. of nBuLi cleanly provided the diethyl ether adducts P(CH2NArR)3Li3(OEt2)1.5 (2a,b). The THF adduct P(CH2NPh)3Li3(THF)5 (2a‐THF) was characterized by X‐ray crystallography. Protonolysis reactions were used to prepare the mononuclear titanium complexes P(CH2NArR)3TiOC6H4tBu (4a,b) and dinuclear species [P(CH2NPh)3TiNMe2]2‐μ‐4,4′{O[3,3′,5,5′‐(C6H2Me2)2]O} (5a), [P(CH2NPh)3Ti]2(μ‐O) (6a), and P(CH2N‐3,5‐Me2C6H3)3Ti‐μ‐O‐Ti(NMe2)3 (7b), from P(CH2NArR)3TiNMe2. The reactions of 1a,b with Zr(NEt2)4 afforded metal complexes of the type P(CH2NArR)3ZrNEt2 (8a,b). The chloride complexes P(CH2NArR)3ZrCl(THF) (9a,b) were prepared by treatment of HNEt3Cl with 1 or 2. The complexes 9a,b reacted with cyclopentadienyllithium (C5H5Li) to produce P(CH2NArR)3ZrCp (10a,b), which were also prepared by the reactions of the lithium salts 2a,b with CpZrCl3. The dilithium salt of the fulvalene dianion (Li2C10H8) reacts with 9a,b to produce the dinuclear complexes trans‐[P(CH2NArR)3Zr]2(μ‐η5:η5‐C10H8) (10a,b), respectively. The facile preparation of transition‐metal‐containing polymers from the bridged dinuclear complexes was illustrated by the reaction of 6a with half an equivalent of [Rh(CO)2(μ‐Cl)]2, which precipitated polymeric Cl(CO)Rh[P(CH2NPh)3Ti]2(μ‐O). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)