Alkylimidotungsten Fluorides and Related Compounds

In this work, tungsten hexafluoride derivatives have been prepared containing the strong pi -donor ligands, the oxo, the imido and the alkylimido groups, with the main emphasis of the work being on the alkylimido derivatives. The compounds WF4X(MeCN) , where X = O or NH, have been prepared by the reaction of WF6 with (Me3Si)2X in acetonitrile. When X = NH, the product is unstable to further reaction. The reactions of primary amines and their trimethyl- silyl analogues with tungsten hexafluoride have been investigated. This has resulted in the identification of compounds of the type, WF4NMe(L), where L = MeCN, EtCN, (MeO)2SO, EtOC(O)CH3 and (MeO)P(O)Me, and the salts RNH3+ WF5NR -, where R = Me, Et and Bu n. The reaction of the amine, Me3SiNHMe, with WF6 gave salts of the anion WF5NMe - and W2F9(NMe)2. In addition the compound, WF3(OMe) (NMe) [(MeO)2 P(O) Me] , has been identified. The reaction of WF6 with BuNH2 gave a very insoluble 1:3 adduct. The following techniques have been used in the study of these compounds; elemental analyses, low and high resolution mass spectrometry, infra red spectrometry Raman spectrometry and n. m. r. spectrometry. The n. m. r. spectra of these compounds have been extensively studied. The n. m. r. evidence shows that the W = N - C skeleton is linear or nearly linear. This is explained in terms of the lone pair of electrons on the nitrogen being fed into empty d-orbitals on the tungsten atom. The reaction of T1WF7 with (Me3Si)2NMe was investigated. The products were Me3SiF and an insoluble cream solid of the composition, T1WF4NMe. The structure was not found, but i. r. and low temperature Raman evidence suggested that it contains the WF4NMe moiety. Related reactions were also investigated, X-Ray powder diffraction was used in these investigations along with the previously mentioned techniques. The reactions of WF6 with Me3SnCF3 and Me3SnC6F5 gave charge transfer complexes. The reactions of MoF6 with Me4Sn or Me3SnCF3 in acetonitrile gave insoluble white solids and MeF, or MeF and CF4