X-RAY STRUCTURE OF (HB(ME2PZ)3)WVIO2(MU-O)WIVO(CO)(HB(ME2PZ)3), A MOLECULE CONTAINING RARE CIS-[WO(CO)]2+ AND SYN-[WVIWIVO3(MU-O)]2+ MOIETIES [HB(ME2PZ)3-=HYDROTRIS(3,5-DIMETHYL-1-PYRAZOLYL)BORATE]

The study of high-valent organometallic oxo complexes has intensified in recent years, and a timely review by Bottomley and Sutin has appeared.2Interest in this area stems from the extensive use of metal oxides as catalysts for organic reactions and the likely involvement of organometallic oxo intermediates in these reactions.3The majority of known species are polynuclear cyclopentadienyl and alkyl complexes of oxophilic early transition metals or cluster µ-3oxo carbonyls of the group 8 and 94metals.2In contrast, noncluster oxo carbonyl complexes are extremely rare. In the early 1980strans-MO2(CO)4(M = MO, W),5,6and MO2(CO)2(M = Cr, Mo, W)6,7were identified by matrix isolation techniques and CrO2(CO)38was obtained in the gas phase. Later that decade the stable oxo carbonyl-W(IV) complex WOCl2-(CO)(PMePh2)2, formed by reaction of WOCl2(PMePh2) 3with CO9or oxidative addition of CO2to WCl2(PMePh2)4,10was reported by Mayer and co-workers. In addition to their relevance to catalysis, complexes containing such electronically disparate ligands are of intrinsic interest. Mixed-valence compounds also attract considerable current interest and early-transition-metal compounds of this type have been exhaustively reviewed.11Approximately 18 dinuclear mixed-valence complexes of tungsten are known, but only the complexes L2WIV(µ-S)2WVIS2(L = C5H5or MeC5H4-)12contain the metal in oxidation states of +4 and +6. We report here the synthesis and X-ray structure of the mixed-valence oxocarbonyl complex |FIB(Me2pz)3jWVI02-0)W,v0(C0)|HB(Me2pz)3| [1; HB(Me2pz)3' = hydrotris(3,5-dimethyl-l-pyrazolyl)borate], formed upon oxidative hydrolysis of NEt4[|HB(Me2pz)3|W(CO)3]. © 1990, American Chemical Society. All rights reserved.