Teflate : an exotic ligand in organometallic chemistry

• Main Author: Crossman, Martin Charles
• Published: University of Leicester 1995
• Subjects: 540
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.674365

The work described within this thesis is concerned with the preparation and characterization of organometallic teflate (-OTeF5) complexes. Herein are reported a range of novel organometallic species utilizing metals from much of the transition series. The cyclopentadienyl complexes, Cp2M(OTeF5)2 [M = Ti , Zr, Hf , Mo ,W] are readily prepared by halide/teflate metathesis reactions of Cp2MCI2 with HOTeF5, and are considered as the first high valent organometallic teflate compounds. Fluoride/teflate metathesis may also be exploited with the carbonyl fluorides and carbonyl phosphine fluorides of osmium and iridium. This route provides evidence for the first instance of an Ir-OTeF5 bond. Non-metathetical methods for introducing the OTeF5 ligand are examined with the oxidation reactions of xenon bisteflate with ; M2(CO)10 [M = Mn , Re], M3(CO)12 [M = Ru , Os], lr4(CO)12 and Ru(CO)3(PPh3)2. This new procedure for preparing low valent metal teflate compounds is assessed and compared with the analogous xenon difluoride reactions. Protonation of Os3(CO)12 in a strong acid (AHF) results in the formation of a hydride bridged cation, [Os3(CO)12H]+. The crystal structure of [Os3(CO)12H] + [W2O2F9]- is reported. The reactivity of cis-(HO)2Tep4, a potential bidentate ligand of high electronegativity is investigated with a variety of compounds ; Cp2TiCl2, cis-(PEt3)2PtCl2 and MFe [M = Mo , W, Te].