Ditungsten Hexa alkoxides

Submitted by ERIN M. BRODERICK, SAMUEL C. BROWNE, and MARC J. A. JOHNSON  

Chemical Sciences and Engineering Division, Aigonne National Laboratory, 9100 South Cass Avenue, Aigonne, IL 60439. 

The checkers dried their solvents by distillation under nitrogen from sodium benzophenone. 

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Insertion of phenyl isocyanate into the metal-oxygen bonds of dimolybdenum or ditungsten hexa-alkoxides " " affords dinnclear derivatives containing two bridging carbamate ligands, as shown in Eq. (2.294) ... 

In addition to the examples of simple addition products already described, dimolybdenum and ditungsten hexa-alkoxides, M2(OR)6(M=M), which are coordinatively unsaturated, react reversibly with donor ligands (L) such as amines and phosphines to form molecules of the type M2(OR)eL2, by simple addition of 2L to M2(OR)e without replacement of any of the alkoxo ligands, according to Eq. (2.300) ... 

The reactions with hydrocarbon solutions of M2(OR>6 (M = Mo, W) compounds with CO are complex, and exhibit some remarkable differences depending on the nature of M and R as well as on the reactions conditions. Novel products have been isolated in the carbonylation of triply bonded dimolybdenum and ditungsten hexa-alkoxides and their adducts as is shown by the reactions described below (Eqs 2.354-2.360). For example, the reactions of terf-butoxides M2(OBu )e with one equivalent of CO in hydrocarbon solvent proceed smoothly at room temperature and attnospheric pressure in two stages ° ° as shown by Eqs (2.354) and (2.355) ... 

Reactions between ditungsten hexa-alkoxides and alkynes have led to a remarkable variety of products, depending on the nature of the alkoxide, the alkyne, and the reaction conditions, as illustrated by Eqs (2.366), (2.368)-(2.370). 

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