A 13C and 19F NMR spectroscopic investigation of the complexes (I), obtained by the reaction of hydrazines and hydrazones with WOF4, shows the existence of isomerism which is due to different orientations of substituents of the coordinated hydrazine.

The reactions of ß2 15 2 with the tungsten hexafluoride or oxide tetrafluoride in the presence of NEt3 in acetonitrile solution have been investigated by multinuclear NMR spectroscopy. The formation of the hydrazido(2-) complex [WOF5(NNMe2)]" and of the complex [WF4(NNMe2)(NHNMe2)]• containing both hydrazido(l-) and hydrazido(2-) ligands was observed. The last one exists as two isomers which involve the dimethylhydrazido(l-) ligand bound in 2 (the major isomer) and 1 forms. The equilibrium between these isomers exists with K -4.7, but no exchange is observed at the temperatures from 248 to 303 K. Complexes [WF4(NNMe2)(T/2-NRNMe2)]' (R = Me, Et) were obtained by reaction of [WOF4(??2-NRNMe2)]" with 1,1-dimethylhydrazine and by the reaction of [WOFs(NNMe2)]-with trimethyl-and 1,1-dimethylethylhydrazine, respectively. No isomers were observed for the two last complexes.

The initial stage of the reaction of hydrazines and hydrazones complex formation with tungsten oxotetrafluoride has been investigated by n.m.r. Neutral complexes of the [WOF4L] type (L  CH3NHNHCH3, (CH3)2NNHCH3, C2H5(CH3)NN(CH3)C2H5, C2H5(CH3)NNHCH3, PhCH3NN(CH3)2, CH3RNNC(CH3)2 R  CH3, C2H5, Ph) have been investigated. The complexes are pentagonal bipyramids with both nitrogen atoms of η2‐coordination with the organic ligands in the equatorial plane. Isomerism of neutral complexes has been found which is due to different orientations of substituents of coordinated hydrazine (hydrazone). An influence of the orientation of substituents to the relative stability of the isomers has been found.