Water-Soluble Tungsten Hydrides: Synthesis, Structures, and Reactions of (C5H4CO2H)(CO)3WH and Related Complexes

Faisal Shafiq, David J. Szalda, Carol Creutz, R. Morris Bullock

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Abstract

The water-soluble metal hydride (C5H4CO2H)(CO)3WH (1) was prepared and characterized. The crystal structure of this complex determined by X-ray diffraction shows it to be dimeric in the solid state, due to OH. . .O hydrogen bonds between the CO2H groups. The pKa of the W-H proton was determined to be 5.8 (±0.2) in water. While the CO2H site of (C5H4-CO2H)(CO)3WH is more acidic than the W-H proton in water, the order of thermodynamic acidity is inverted in organic solvents. Deprotonation of (C5H4CO2H)(CO)3WH with KH in THF, followed by counterion exchange, gives [(C5H4CO2H)(CO)3W] -NBu4+ (2). This anion is also dimeric through intermolecular hydrogen bonding of the CO2H groups, as shown by X-ray crystallography. The reaction of PMe3 or P(OMe)3 with (C5H4CO2H)(CO)3WH gives substitution of a CO ligand and formation of (C5H4CO2H)(PR3)(CO)2WH (R = Me, OMe). Reaction of PTA (PTA = phosphatriazaadamantane) with (C5H5)(CO)3WH gives (C5H5)(PTA)-(CO)2WH. This complex exists as an equilibrating cis/trans mixture in solution, but was crystallized as the trans isomer, as shown by X-ray crystallography. Water solubility of (C5H5)(PTA)(CO)2WH was negligible. The water-soluble metal-metal-bonded bimetallic complexes [(C5H4CO2H)(CO)3W]2, [(C5H4CO2H)(PMe3)(CO) 2W]2, and {(C5H4CO2H)[P(OMe)3]-(CO) 2W}2 were prepared by reaction of the metal hydrides with trityl radical (Ph3C).

Original languageEnglish
Pages (from-to)824-831
Number of pages8
JournalOrganometallics
Volume19
Issue number5
Publication statusPublished - Mar 6 2000

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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