An NMR spectroscopic study of the binding of alkali metal cations and methanol by cis-Mo(CO)4{Ph2P(CH2CH2O) nCH2CH2PPh2-P,P′} (n = 4, 5) metallacrown ethers. The X-ray crystal structures of cis-Mo(Co)4{Ph2P(CH2CH2O) 4CH2CH2PPh2-P,P′}·MeOH

Academic Article

Abstract

  • The equilibrium constants for the binding of Li and Na by the cis-Mo(CO) {Ph P(CH CH O) CH CH PPh -P,P′} (n = 4 (1), 5 (2)) metallacrown ethers have been determined by fitting the NMR data from titrations to a one-to-one binding model using non-linear least squares techniques. These show that 1 has an approximately equal affinity for Li and Na but that 2 has a much larger affinity for Na than for Li . The X-ray crystal structures of cis-Mo(CO) {Ph P(CH CH O) CH CH PPh -P,P′}·MeOH, 3, (a, 13.602(2); b, 16,211(2); 8.394(2) Å ; β, 101.26(1)°; monoclinic; P2 /n; Z, 4) and cis-Mo(CO) {Ph P(CH CH O) CH CH PPh -P,P′}·H O, 4, (a, 13.228(3); b, 20.336(4); c, 14.837(1) Å; β, 108.68(1)°; monoclinic; P2 /c; Z, 4) have been determined. Both the methanol in 3 and the water in 4 are hydrogen bonded to ether oxygens in the metallacrown ether rings. In wet acetonitrile-d , the binding of the methanol to the metallacrown ether ring in 3 slows proton exchange between water and methanol so that coupling between the hydroxyl and methyl protons is observed. This coupling disappears when LiBF is added to the solution. + + + + + + 4 2 2 2 n 2 2 2 4 2 2 2 4 2 2 2 1 4 2 2 2 4 2 2 2 2 1 3 4
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    Author List

  • Gray GM; Fish FP; Duffey CH
  • Start Page

  • 229
  • End Page

  • 240
  • Volume

  • 246
  • Issue

  • 1-2 SPEC. ISSUE