An NMR spectroscopic study of the reactions of (2-(2-methoxyethoxy)ethyl)diphenylphosphine with rhodium(I) olefin complexes

Academic Article

Abstract

  • The reactions of Ph P(CH CH O) CH (I) with [(cod)Rh(μ-Cl)] and [(coe) Rh(μ-Cl)] (cod = 1,5-cyclooctadiene, coe = cis-cyclooctene) and of Ph PMe with [(coe) Rh(μ-Cl)] have been studied using P and C NMR spectroscopy. These studies indicate that the two Rh complexes give quite different reaction products. The reaction of I with [(cod)Rh(μ-Cl)] at a Rh/I ratio of 1/1 yields (cod)RhPh P(CH CH O) CH -PCl (II). Increasing the Rh/I ratio in this solution to 1/2 results in the formation of ClRhPh P(CH CH O) CH -P (III), but not of any complexes with two I's coordinated to Rh. A complex with two I's attached to the Rh can be formed by first reacting II with AgBF to form [(cod)RhPh P(CH CH O) CH -P,O]BF (IV) and then by reacting IV with a second equivalent of I to form [(cod)RhPh P(CH CH O) CH -P ]BF (V). The reaction of [(coe) Rh(μ-Cl)] with Ph PMe yields [(coe)(Ph PMe)Rh(μ-Cl)] (VI) at a Rh/Ph PMe ratio of 1/1, [(Ph PMe) Rh(μ-Cl)] (VII) at a Rh/Ph PMe ratio of 1/2 and ClRh(Ph PMe) (VIII) at a Rh/Ph PMe ratio of 1/3. The reaction of [(coe) Rh(μ-Cl)] with I gives a different product, [Ph P(CH CH O) CH -P,ORh(μ-Cl)] (IX) at a Rh/I ratio of 1/1, but similar products at Rh/I ratios of 1/2, [Ph P(CH CH O) CH -P Rh(μ-Cl)] (XI) and 1/3, III. The differences in the reaction products are due to the fact that the bidentate cod ligand coordinates much more strongly to the Rh than do either the bridging chlorine or the monodentate coe ligand. Thus, the reactions of [(cod)Rh(μ-Cl)] with phosphines initially involve displacement of the bridging chloride, but those of [(coe) Rh(μ-Cl)] with phosphines initially involve loss of the coe ligand. The weak Rh-coe bond allows I to function as a chelating P/O-ligand in IX. © 1990. 2 2 2 2 3 2 2 2 2 2 2 2 2 2 2 2 3 2 2 2 2 3 3 4 2 2 2 2 3 4 2 2 2 2 3 2 4 2 2 2 2 2 2 2 2 2 2 2 3 2 2 2 2 2 2 2 3 2 2 2 2 2 3 2 2 2 2 2 31 13
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    Author List

  • Sen Reddy VV; Varshney A; Gray GM
  • Start Page

  • 259
  • End Page

  • 266
  • Volume

  • 391
  • Issue

  • 2