Preparation of trichloro- and tribromocyclopentadienyltungsten(IV)

Abstract

The thermal decarbonylation of (Ring)WX 3 (CO) 2 in refluxing toluene has led to the preparation of the CO-free compounds [(Ring)WX 3 ] 2 [Ring =h 5 -C 5 H 5 (Cp) and X=Cl (1a) or Br (1b); Ring= h 5 -C 5 H 4 Me (Cp%), X= Cl (2a) or Br (2b); Ring=h 5 -C 5 Me 5 (Cp*), X =Cl (3)]. The NMR properties of these molecules are consistent with diamagnetism and thereby indicate a different structure from that of the paramagnetic molybdenum analogues. Compounds 1a and 2a react with dppe to afford mononuclear 18-electron adducts, (Ring)WCl 3 (dppe) (Ring=Cp (4) or Cp% ( 5)). The X-ray structure of 5 shows a pseudo-fac-octahedral geometry with the dppe ligand occupying two equatorial (e.g. cis relative to Cp%) coordination sites. The X-ray structure of two by-products of the synthetic processes are also reported, e.g. Cp% 3 W 3 Cl 3 (m 2 -Cl) 2 (m 3 -O) ( 6) and [Cp*WCl 3 ] 2 (m-O) (7).

High oxidation state organomolybdenum and organotungsten chemistry in protic environments

“…[76,[124][125][126][127][128][129][130] which are convenient starting materials for further synthetic work. Reductive studies of cyclopentadienyl imido precursors in anhydrous solvents have given access to a number of organometallic derivatives containing ligands (alkenes, alkynes, .…”