Cp[subscript 2]TiCI[subscript 2]: Synthesis, Characterization, Modeling and Catalysis

As an alternative to the traditional metallocene laboratory targets, students synthesize Cp[subscript 2]TiCl[subscript 2], bis([eta][superscript 5]-cyclopentadienyl)dichloridotitanium(IV), from the mildly moisture-sensitive cis-TiCl[subscript 4](thf)[subscript 2]. Air-free handling techniques are emphasized, but the (mostly) air-stable, diamagnetic product is then easily characterized by NMR spectroscopy as well as mass spectrometry and infrared (IR) spectroscopy. This student-generated product is then used as (1) a starting material in the production of the difluoride analogue, Cp[subscript2]TiF[subscript 2], and (2) a catalyst for "in situ" formation of allyl zinc bromide for use in a simple, model Barbier reaction. An additional supplement is also included in which students model the title compound with varying hapticities of the cyclopentadienyl rings. These data are aligned with experimental NMR and IR spectra to support and explain students' findings.