Unusual hydrolysis reactions of cis-Bis((2,2′-biphenylylene) phosphochloridite ester)tetracarbonylmolybdenum(O)

Academic Article

Abstract

  • The hydrolysis of cis-Mo(CO) 4(2,2′-C 12H 8O 2PCl) 2 (1) in the presence of excess triethylamine and water yields [(C 2H 5) 3NH] 2[cis-Mo(CO) 4(2,2′-C 12H 8O 2PO) 2] (2). This complex is in equilibrium with [(C 2H 5) 3NH][cis-Mo(CO) 4(2,2′- C 12H 8O 2PO)(2,2′-C 12H 8O 2POH)] (3) and free triethylamine in solution. The hydrolysis of 1 with a stoichiometric amount of triethylamine and water yields only 3. A Scatchard plot for the reaction of 3 and triethylamine to form 2 at 25 °C gives an equilibrium constant of 5.8 × 10 -3 for the reaction. Fitting the variable-temperature 31P{ 1H} NMR spectra of a CD 2Cl 2 solution of 3 and 0.5 equiv of triethylamine using the gNMR program gives an activation energy of 47.4 kJ/mol for the reaction. The diastereomers of 3 crystallize with very different morphologies, allowing the X-ray crystal structures of both enantiomers to be determined. The 3R*JB* diastereomer crystallizes in the noncentrosymmetric P2 12 12 1 space group, but the 3R*S* diastereomer crystallizes in the centrosymmetric P2 1/c space group. The most interesting feature of the structures of 3R*R* and 3R*S* is the strong, intramolecular hydrogen bonding between the 2,2′-C 12H 8O 2-POH and 2,2′-C 12H 8O 2PO - ligands that result in short O-O distances in both enantiomers (2.520(6) Å in 3R*R* and 2.373(11) Å in 3R*S*). The hydrogen bonding in both diastereomers is asymmetric, in contrast to previous speculation in the literature.
  • Authors

    Published In

  • Organometallics  Journal
  • Digital Object Identifier (doi)

    Pubmed Id

  • 18337761
  • Author List

  • Byrd H; Harden JD; Butler JM; Jablonsky MJ; Gray GM
  • Start Page

  • 3239
  • End Page

  • 3245
  • Volume

  • 23
  • Issue

  • 13