Properties and x-ray structure of bis(triphenylphosphine)nitrogen(1+) cis-tricarbonylhydridotris(triphenyl phosphite)ferrate(1-), an unexpected structural isomer
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The preparation of [PPN] [HFe(CO)3P(OPh)3] (1) has been carried out by using an alcoholic hydroxide reaction with Fe-(CO)4P(OPh)3; the same synthesis was reported earlier for trans-HFe(CO)3PR3- salts. After spectral and chemical differences were observed between the anion of 1 and all other HFe(CO)3PR3- anions, which have been shown to exist in a trans configuration of H and PR3(TBP geometry), an X-ray structural determination was performed. 1 crystallizes in the triclinic system, space group PĪ, with cell parameters a = 10.491 (3) Å, b = 13.963 (4) Å, c = 18.687 (6) Å, a = 108.19 (2)°, β = 105.47 (2)°, ϒ= 93.16 (2)°, V = 2478 (1) Å3, and Z=2. The hydride ligand was located in the axial position of a distorted trigonal bypyramid, but curiously the P(OPh)3ligand is in the equatorial plane, cis to the hydride. Unique properties of 1 include its air stability and its rigidity as the cis isomer. The spectral properties of 1 including ion pairing and isotopic H/D exchange effects were examined. In contrast to other anion trigonal-bipyramidal complexes that show equatorial CO⋯Na+interaction, an axial CO—Na+site interaction was observed for 1. Hydrogen/deuterium substitution in this anion revealed a large v(MH) to v(CO) coupling to the trans carbonyl group. © 1987, American Chemical Society. All rights reserved.
author list (cited authors)
Ash, C. E., Kim, C. M., Darensbourg, M. Y., & Rheingold, A. L.