ORGANOIMIDO AND ORGANODI-IMIDO VANADIUM COMPLEXES

Reactions of the p-tolylimido vanadium(V) complex [V(NTol)Cl-3], 1, wi th sodium dithiocarbamate salts Na[S2CNR2] yield an homologous series of organoimido vanadium(V) dithiocarbamate systems [TolN=(S2CNR2)(x)Cl (3-x)] [x = 1:R = Et (2a), Me (2b); x = 2: R = Et (3a), Me (3b); x = 3 :R = Et (4a), Me (4b)]; the electronic and V-51 NMR spectra of these c omplexes are described. Zn reduction of complexes 3 affords impure pro ducts whose ESR spectra are consistent with the presence of the V(IV) systems [V(NTol) (S2CNR2)(2)], 5. Reaction of VOCl3 with 0.5 equiv. of p-OCN-C6H4-NCO yields the p-phenylenediimido complex [Cl3V=NC6H4N=VCl 3], 6. Dissolution of 6 in THF produces an adduct [(THF)(3)Cl3V=NC6H4N =VCl3(THF)(3)], 7, whose THF ligands are weakly bound. VOCl3 reacts wi th an equimolar amount of p-OCN-C6H4-NCO to produce the mononuclear co mplex p-[Cl3V=NC6H4-NCO], 8. The reaction of 8 with OWCl4 in refluxing toluene affords an insoluble product analyzing as the expected hetero binuclear system [Cl3V=NC6H4N=WCl4], 9, but treatment of this product with THF yields a mixture shown by H-1 NMR to contain both 7 and its d itungsten analogue [(THF)Cl4W=NC6H4N=WCl4(THF)], indicating that an un usual intermetallic exchange of imido ligands has occurred. The chlori de ligands of 6 can be substituted by [S2CNEt2] or [(OBu)-Bu-t] anions to afford [(Et2NCS2)(3)V=NC6H4N=V(S2CNEt2)(3)], 11, and [((BuO)-Bu-t) (3)V=NC6H4N=V(O'Bu)(3)], 12, respectively. (C) 1998 Elsevier Science L td. All rights reserved.