Tantalum(V) fluoride complexes of thio- and seleno-ether ligands and a comparison with the TaX5 (X=Cl or Br) analogues

• Published in: Journal of fluorine chemistry Vol. 137; pp. 77 - 84
• Main Authors: Benjamin, Sophie L., Hyslop, Alison, Levason, William, Reid, Gillian
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2012
• Subjects: Cations; Crystal structure; Crystals; Iridium; Ligands; Moisture; NMR spectroscopy; Selenoether; Tantalum pentafluoride; Thioether; X-ray structures; X-rays; Thioether; Selenoether; Tantalum pentafluoride; X-ray structures
• ISSN: 0022-1139; 1873-3328
• DOI: 10.1016/j.jfluchem.2012.02.014

Synthesis and characterisation of the very rare examples of TaF5 complexes with soft donor ligands are reported, and the properties compared to analogues with TaCl5 and TaBr5. [Display omitted] ► Synthesis and characterisation of a series of neutral, soft donor (S or Se) complexes of tantalum pentafluoride. ► The first structurally characterised soft donor (thioether) complexes of TaF5. ► Comparisons of the chemistry of TaF5 with TaCl5 and TaBr5 with neutral S and Se ligands. ► Both six- and eight-coordination are found in TaF5 adducts, whereas TaCl5/TaBr5 favour six-coordination. Reaction of TaF5 with SMe2 and RS(CH2)2SR (R=Me, Et or iPr) in anhydrous CH2Cl2 solution produce colourless, extremely moisture sensitive crystals of [TaF4(SMe2)4][TaF6] and [TaF4{RS(CH2)2SR}2][TaF6] respectively, which contain eight-coordinate cations and octahedral anions, whereas TaF5 reacts with neat SR2 (R=Me or Et) to form six-coordinate [TaF5(SR2)]. Very unstable [TaF5(SeMe2)] and [(TaF5)2{μ-MeSe(CH2)2SeMe}] were isolated with the selenoether ligands and also contain six-coordinate tantalum species. Selected complexes of TaCl5 and TaBr5 have been prepared for comparison. The complexes have been characterised by IR, UV/visible and 1H and 19F{1H} NMR spectroscopies, and X-ray crystal structures are reported for [TaF4{MeS(CH2)2SMe}2][TaF6], [(TaCl5)2{μ-MeSe(CH2)2SeMe}] and [TaCl5(SeMe2)].