Halide Tungsten II Complexes of Tris 3,5-dimethylpyrazolyl hydroborate

CARBONYL HALIDE TUNGSTEN(II) COMPLEXES OF TRIS(3,5-DIMETHYLPYRAZOLYL)HYDROBORATE 

Submitted by SIMON THOMAS and CHARLES G. YOUNG Checked by BRADFORD BROCE and JOSEPH L. TEMPLETON  

In 1969, Trofimenko reported the first organometallic compounds to contain the tris(3,5-dimethylpyrazolyl)hydroborate ligand (Tp ) these included salts of the group 6 tricarbonyl anions, [Tp M(CO)3] (M = Cr, Mo, W). Since then the coordination and organometallic chemistry of scorpionate ligands has developed into an important subdiscipline of inorganic chemistry. In contrast to the very considerable synthetic utility of the tricarbonyl anions, carbonyl halide complexes have played only a limited role in the development of the group 6 chemistry of Tp.  

However, syntheses for carbonyl halide complexes of tungsten, e.g., Tp WX(CO)3 and Tp WX(CO)2, now available and a comprehensive account of the properties of these compounds has appeared. As expected, compounds of this type are valuable starting materials for low-valence organometallic and high-valence coordination compounds (upon oxidative decarbonylation). The acetonitrile-K A, C complexes, Tp WX(MeCN)(CO), reported by Thomas et al., are also valuable precursors for a variety of organometallic complexes the iodide is the most readily accessible derivative of this type. ° We report here syntheses for NEt4[Tp W(CO)3], the chloro, bromo, and iodo members 

School of Chemistry, University of Melbourne, Victoria 3010, Australia, t Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290. 

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