Document Type

Article

Publication Date

Spring 3-29-2017

Publication Title

Journal of Organometallic Chemistry

Department

Chemistry

Abstract

The synthesis, characterization and catalytic activity of new ruthenium complexes of fluorinated triarylphosphines is described. The new ruthenium complexes [RuCl(ind)(PPh3){P(p-C6H4CF3)3}] and [RuCl(ind)(PPh3){P(3,5-C6H3(CF3)2)3}] were synthesized in 57% and 24% isolated yield, respectively, by thermal ligand exchange of [RuCl(ind)(PPh3)2], where ind = indenyl ligand η5-C9H7−. The electronic and steric properties of the new complexes were studied through analysis of the X-ray structures and through cyclic voltammetry. The new complexes [RuCl(ind)(PPh3){P(p-C6H4CF3)3}] and [RuCl(ind)(PPh3){P(3,5-C6H3(CF3)2)3}] and the known complex [RuCl(ind)(PPh3)2}] differed only slightly in their steric properties, as seen from comparison of bond lengths and angles associated with the ruthenium center. As determined by cyclic voltammetry, the redox potentials of [RuCl(ind)(PPh3){P(p-C6H4CF3)3}] and [RuCl(ind)(PPh3){P(3,5-C6H3(CF3)2)3}] are +0.173 and + 0.370 V vs. Cp2Fe0/+, respectively, which are substantially higher than that of [RuCl(ind)(PPh3)2] (−0.023 V). After activation through chloride abstraction, the new complexes are catalytically active in the etherification of propargylic alcohols (8–24 h at 90 °C in toluene, 1–2 mol% catalyst loading, 29–61% isolated yields). As demonstrated by a comparative study for a test reaction, the three precursor complexes [RuCl(ind)(PPh3){P(p-C6H4CF3)3}], [RuCl(ind)(PPh3){P(3,5-C6H3(CF3)2)3}] and [RuCl(ind)(PPh3)2}] differed only slightly in catalytic activity.

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