Binuclear metal carbonyl DAB complexes. III. Activation of a CN double bond in Ru2(CO)6(DAB) complexes (DAB = 1, 4-diazabutadiene). C C bond formation between two DAB ligands

Abstract

Recently a variety of mono-and dinuclear metal carbonyl DAB complexes (DAB = 1,4-diazabutadiene = crdiimine) have been prepared and the electronic and spectroscopic properties investigated [l-6].In almost all complexes the DAB ligand is u, acoordinated to the metal carbonyl fragment via the two lone pairs on nitrogen. Only one example has been reported where the nelectrons were involved in the metal-to-ligand bonding [7], while for some reactions of coordinated DAB ligands R-coordinated intermediates were assumed [8].In this preliminary paper on ruthenium carbonyl DAB complexes, the earlier assumption that ncoordination is very important for the activation of the C=N double bond will be shown to be correct. Ruthenium carbonyl reacts with DAB ligands according to equation (1).2/3Ru3(CO)r2 + DAB + Ru~(CO)~DAB + 2C0 (1)

Oxidation of phenacetin and related amides to their hydroxamic acids. Crystal structures of the dioxomolybdenum(VI) hydroxamates derived from phenacetin and acetanilide

“…The predominant cooridnation mode is chelate ring formation via the two lone pairs on nitrogen,1-8 but recently the monodentate and -, -' bridging modes have also been established.9,10 Involvement of the electrons of the N=C-C=N skeleton in the coordination toward methyl carbonyl complexes has been the subject of extensive investigations. A series of binuclear metal carbonyl complexes of the general formula MM'-(CO)6(DAB) has been synthesized ( = M' = Fe,11 Ru, 12,13 Os;14 = Co and M' = Mn, Re. 15 In all these complexes the DAB ligand is coordinated via the two lone pairs on nitrogen and via one pair of electrons, thus being a six-electron donating system.…”

Dinuclear and Polynuclear Ruthenium Non-cluster Compounds

“…The mixed metal complex [FeRu(CO) 6 (dab)] forms a mixture of two isomers, and is prepared from [Ru 3 (CO)i 2 ] and [Fe(CO) 3 (dab)]. 89 …”