The synthesis and structure of a novel beta-diketiminato Co(I) arene adduct [Me2NN]Co(eta6-toluene) (2) are described, that serves as a synthon to the reactive, "naked" 12-electron [Me2NN]Co fragment via loss of toluene in its reactions with dioxygen, organoazides, and a nitrosobenzene. Exposure of 2 to dioxygen in ether leads to {[Me2NN]Co}2(mu-O)2 (3), a rare example of a cobalt-oxo complex thermally stable at room temperature. The X-ray structure of 3 reveals a short Co-Co separation of 2.716(4) A and exhibits positional disorder for the bridging oxo groups; the predominant configuration contains oxygen atoms in square-planar sites with short Co-O distances (1.784(3) and 1.793(4) A). Reaction of 2 with organoazides N3R (R = 3,5-Me2C6H3 (Ar) or 1-adamantyl (Ad)) results in the formation of imido complexes whose structure depends on the nature of the azido substituent. The synthesis and structures of both {Me2NN]Co}2(mu-NAr)2 (4) with arylimido groups in tetrahedral bridging sites or the three-coordinate, 16-electron [Me2NN]CoNAd (5) are described. The X-ray structure of terminal imide 5 reveals a short Co-N bond distance (1.624(4) A) and only somewhat bent imido linkage (Co-N-C = 161.5(3) degrees ) consistent with a significant degree of multiple bond character. Complex 2 cleaves the O=N bond of the nitrosobenzene O=NAr (Ar = 3,5-Me2C6H3) to form the binuclear oxo-imido complex {[Me2NN]Co}2(mu-O)(mu-NAr) (6) that possesses a structure intermediate between square-planar 3 and tetrahedral 4 in which the [Me2NN]Co fragments are mutually orthogonal.

Monovalent nickel and copper beta-diketiminato complexes react with ArN=O (Ar = 3,5-Me(2)C(6)H(3), Ph) to give C-nitroso adducts that exhibit three different modes of bonding with varying degrees of N-O bond activation. The addition of ArNO to 2 equiv of [Me(2)NN]Ni(2,4-lutidine) {[Me(2)NN](-) = 2,4-bis(2,6-dimethylphenylimido)pentyl} gives {[Me(2)NN]Ni}(2)(mu-eta(2):eta(2)-ONAr) (1a and 1b), which exhibit symmetrical bonding of the ArN=O moiety between two [Me(2)NN]Ni fragments, with a N-O bond distance of 1.440(4) A in 1a that is significantly longer than those in free C-organonitroso compounds (1.13-1.29 A). [Me(2)NN]Cu(NCMe) reacts with 0.5 equiv of ArNO in ether to give the dinuclear adducts {[Me(2)NN]Cu}(2)(mu-eta(2):eta(1)-ONAr) (2a and 2b), which exhibit eta(2) and eta(1) bonding of the ArN=O moiety with separate [Me(2)NN]Cu fragments possessing N-O distances of 1.375(6) A (2a) and 1.368(2) A (2b). In arene solvents, one beta-diketiminatocopper(I) fragment dissociates from 2 to give [Me(2)NN]Cu(eta(2)-ONAr) (3a and 3b), which may be isolated by the addition of 1 equiv of ArNO to [Me(2)NN]Cu(NCMe). The X-ray structures of 3a and 3b are similar to those of related Cu(I) alkene adducts, with N-O distances in the narrow range 1.333(4)-1.338(5) A. IR spectra of the nitrosobenzene adducts 1b, 2b, and 3b exhibit nu(NO) stretching frequencies at 915, 1040, and 1113 cm(-1), respectively, following the decreasing degree of N=O activation observed in the X-ray structures of species 1, 2, and 3. Both 1a and 3a react with anaerobic NO(g) to give the corresponding N-aryl-N-nitrosohydroxylaminato complexes [Me(2)NN]M(kappa(2)-O(2)N(2)Ar) [M = Ni (4), Cu (5)]. In the reaction of dinuclear 1a with NO, one [Me(2)NN]Ni fragment is trapped as the nickel nitrosyl [Me(2)NN]Ni(NO). Reaction of the monovalent complex [Me(2)NN]Cu(eta(2)-ONAr) with NO(g) to give divalent [Me(2)NN]Cu(kappa(2)-O(2)N(2)Ar) represents an example of oxidative nitrosylation.

Ein NO‐vum: Ein Kupfer(I)‐β‐diketiminat aktiviert das Nitrosamin Ph2NNO unter Bildung eines seltenen, dreifach koordinierten Kupfer(II)‐amids, 1. Die Reaktion dieses Amids mit NO‐Gas setzt Ph2NNO wieder frei und liefert eine gemischtvalente Spezies mit NO‐funktionalisierten β‐Diketiminatliganden (2; Cu hellblau, N dunkelblau, O rot). Somit können an einem gewöhnlichen Kupferzentrum Spaltung und Bildung der R2N‐NO‐Bindung gleichermaßen stattfinden.

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A NO‐velty: A copper(I) β‐diketiminate activates the nitrosamine Ph2NNO to give a rare, three‐coordinate copper(II) amide, [(Me2NN)CuNPh2]. Reaction of this amide with NOgas returns Ph2NNO as well as a mixed‐valence species with NO‐functionalized β‐diketiminate ligands (see scheme; Cu light blue, N dark blue, O red). Thus, both the cleavage and formation of R2NNO bonds may take place at a common copper center.

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