Aminotroponiminate and a related diimine as ligands for tungsten complexes

Reaction of N-isopropyl-2-(isopropylamino)troponimine, {(i-Pr)(2)ATI}H, with fac-[W(CO)(3)(NCMe)(3)] yield the complex tungsten-tetracarbonyl-N,N'-diisopropyl-1,2-diimino-3,5-cycloheptadiene (1), in which the ligand is tautomerized from the enamino to the imino isomer. As a result of the rearrangement the conjugate 10pi electron system of the ligand is destroyed. Further, treatment of compound 1 with an excess of KH in THF leads to the ionic complex [K(THF)(2)][W-Pr)(2)ATI}W(CO)(4)] (2). In the presence of diglyme the corresponding complex [K(diglyme)(2)]{(i-Pr)(2)ATI}-W(CO)(4)] (3) is obtained. All compounds have been characterized by spectroscopic methods. Complex 1 has also been investigated by single crystal X-ray diffraction.