Metallocene derivatives of early transition elements. Part 4. Synthesis and crystal structures of a series of zirconocene(IV) halides [Zr(η-C 5H4SiMe3)2X2] (X = Cl or Br) and [Zr{η-C5H3(SiMe3) 2-1,3}2X2] (X=F, Br, or I)

Antonio Antiñolo, Michael F. Lappert, Anirudh Singh, Duncan J.W. Winterborn, Lutz M. Engelhardt, Colin L. Raston, Allan H. White, Arthur J. Carty, Nicholas J. Taylor

Research output: Contribution to journalArticle

Abstract

A series of zirconocene(IV) halides, [Zr(η-C5H 4SiMe3)2X2] [X = Cl (1) or Br (2)] and [Zr{η-C5H3(SiMe3)2-1,3} 2X2] [X = F (3), Br (4), I (5), or Cl (6)], has been prepared, either by (i) substitutive procedures from ZrCl4 [involving the following ligand exchanges: Cl-/C5H 4SiMe3-, Cl-/C5H 3(SiMe3)2-, Cl-/Br -, Cl-/I-, or Cl-/NMe 2- followed by NMe2-/F-], or (ii), for complexes (3), (5), or (6), by oxidative addition to [Zr{η-C5H3(SiMe3)2-1,3} 2(CO)2]. The only νasym(ZrX2) vibration to be assigned with confidence is for X = F at 563 cm-1; 1H and 13C n.m.r. data are unexceptional. X-Ray structure determinations of complexes (1)-(5) have been carried out. Their molecular symmetry is close to 2, or crystallographically imposed 2 in (3), with the stereochemistry about the metal centre best described as distorted tetrahedral. The angle X-Zr-X is 93.70(7), 94.2(1), 100.5(3), 100.25(5), and 100.37(4)° for the halides (1)-(5), respectively; and the corresponding centroid-Zr-centroid angles are 129.1, 128.2, 131.4, 131.4, and 131.8°. Metal-halogen distances in (1) [2.505(2) and 2.476(2) Å] and (3) [2.212(6] Å are significantly longer than in the parent zirconocene(IV) halides [Zr(η-C5H5)2X2] (cf. 2.44 Å for X = Cl and 1.98 Å for X = F) as are [by ca. 0.04 Å (average)] the metal-centroid distances in (3)-(5).

Original languageEnglish
Pages (from-to)1463-1472
Number of pages10
JournalJournal of the Chemical Society, Dalton Transactions
Issue number6
DOIs
Publication statusPublished - Jun 1987
Externally publishedYes

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