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 10 π 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 ][{( i ‐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.