Andreas A. Danopoulos, Robyn S. Hay-Motherwell, Geoffrey Wilkinson, Sean M. Cafferkey, Tracy K. N. Sweet and Michael B. Hursthouse
Interaction of N3R with Ir(mes)3 (mes = mesityl, C6H2Me3-2,4,6) gave products dependent on the nature of the azide. When R = mes, the tetrazenido amide complex 1 is obtained in which dehydrogenative coupling of the mesityl groups via the o-methyls has occurred; thermolysis of 1 in toluene resulted in cleavage of the tetrazene ring and formation of amide complex 2. When R = Ph, the aryl tetrazenido amide complex 3 is formed. Photolysis of a mixture of N3(mes) and [RuCl2(PPh3)3] followed by phosphine exchange gave the tetrazene complex [RuIICl2{N4(mes)2 }(PMe3)2] 4. Thermal reaction of [RuCl2H2(PPri3)2] with N3(mes) gave the triazenophosphorane complex [RuCl3(PPri3){N3(mes) PPri3}] 5. The ruthenium allyl amide [Ru(PMe3)3{NHC6H3Pr i(η3-CH2CCH2)}] 6 bearing a new hybrid ligand was obtained by interaction of trans-[RuCl2(PMe3)4] with Li[NH(C6H3Pri2-2,6)] in di-n-butyl ether. Plausible reaction mechanisms accounting for the formation of the new compounds are proposed. Finally, the crystal structures of the complexes 1–6 have been determined. Complexes 1 and 2 have pseudo-square planar geometries involving the olefin formed by the coupled methyl groups of two mesityls and three (1) or two (2) amide nitrogens and a chlorine atom (2). Compound 3 has a trigonal bipyramidal metal centre with the axial Ir–N amide bonds longer than the equatorial ones; 4 has an octahedral structure with a bidentate tetragonal ligand and trans phosphines whilst 5 is distorted octahedral with a N,N-chelating phosphazide ligand. Complex 6 is also octahedral with the allyl groups occupying cis sites and the three Ru–P bonds in a facial arrangement.