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Controlling and understanding charge state and metal coordination in carbon nanomaterials is crucial to harnessing their unique properties. Here we describe the synthesis of the well‐defined fulleride complex [{(Mesnacnac)Mg}6C70], 2, (Mesnacnac)=HC(MeCNMes)2, Mes=2,4,6‐Me3C6H2, from the reaction of the β‐diketiminate magnesium(I) complex [{(Mesnacnac)Mg}2] with C70 in aromatic solvents. The molecular structure of complex 2 was determined, providing the first high‐quality structural study of a complex with the C706− ion. In combination with solution state NMR spectroscopic and DFT computational studies, the changes in geometry and charge distribution in the various atom and bond types of the fulleride unit were investigated. Additionally, the influence of the (Mesnacnac)Mg+ cations on the global and local fulleride coordination environment was examined. [ABSTRACT FROM AUTHOR]

Three extremely bulky 1,3,5-triazapentadienes, [sup.Ar]NNNH ([sup.Ar]NNN=N[{C([Bu.sup.t])=N(Ar)}.sub.2]; Ar=Mes (mesityl), Dep (2,6-diethylphenyl), or Dip (2,6-diisopropylphenyl)) have been prepared and structurally characterized. These are readily deprotonated, yielding a series of lithium and potassium triazapentadienyl complexes, one of which, ([sup.Dip]NNN)Li, has been structurally characterized. Similarly, three monomeric triazapentadienyl magnesium iodide complexes, ([sup.Ar]NNN)MgI(O[Et.sub.2]), and a dimeric calcium counterpart, [{([sup.Mes]NNN)Ca(THF)([mu]-I)}.sub.2], have been prepared. Attempts to reduce the former gave homoleptic bis(triazapentadienyl) magnesium complexes, [([sup.Ar]NNN).sub.2]Mg (Ar = Mes or Dep) as the main products. One reaction also gave a very low yield of the magnesium(I) dimer, [{([sup.Dep]NNN)Mg-}.sub.2], which was structurally characterized. In related chemistry, two triazapentadienyl boron difluoride compounds, ([sup.Ar]NNN)B[F.sup.2] (Ar = Mes or Dep), have been synthesized, and unsuccessful attempts have been made to reduce these to boron(I) heterocycles. For sake of comparison, attempts have been made to prepare a series of related amino-substituted [beta]-diketiminato group 13 element(I) heterocycles. Although these were also not successful, several group 13 element(III) halide complexes incorporating this ligand class have been characterized. Key words: triazapentadienyl, steric bulk, [beta]-diketiminate, group 2, group 13, magnesium(I). Nous avons synthétisé trois 1,3,5-triazapentadiènes extrêmement encombrés de formule [sup.Ar]NNNH [[sup.Ar]NNN = N[{C([Bu.sup.t])= N(Ar)}.sub.2]; Ar = Mes (mésityl), Dep (2,6-diéthylphényl) ou Dip (2,6-diisopropylphényl)] et les avons caractérisés du point de vue structural. Ces composés sont facilement déprotonés, formantune série de complexes de type triazapentadiényle avec le lithium et le potassium. La caractérisation de l'un d'entre eux, le ([sup.Dip]NNN)Li, a permis d'en révéler la structure. De manière similaire, nous avons préparé trois complexes monomériques d'iodure de magnésium de type triazapentadiényl, de formule ([sup.Ar]NNN)MgI(O[Et.sub.2]), et un analogue dimérique complexé avec le calcium, le [{([sup.Mes]NNN)Ca(THF)([mu]-I)}.sub.2]. En tentant de réduire ces trois premiers complexes, nous avons obtenu les complexes homoleptiques de type bis(triazapentadiényl)magnésium de formule [([sup.Ar]NNN).sub.2]Mg (Ar = Mes ou Dep) comme produits majoritaires. Dans une réaction, nous avons également obtenu un très faible rendement du dimère de magnésium(I) [{([sup.Dep]NNN)Mg-}.sub.2], que nous avons caractérisé pour en confirmer la structure. En employant une approche similaire, nous avons synthétisé deux composés de type difluorure de triazapentadiénylbore, de formule ([sup.Ar]NNN)B[F.sup.2] (Ar = Mes ou Dep), et notre tentative de réduire ces hétérocycles de bore(I) s'est révélée infructueuse. À titre de comparaison, nous avons tenté de préparer une série d'hétérocycles dérivés de type [beta]-dicétiminate portant des substituants amines, complexés avec des éléments(I) du groupe 13. Bien que ces dernières tentatives aient également été sans succès, nous avons caractérisé plusieurs complexes d'halogénures d'éléments(III) du groupe 13 portant des ligands de cette classe. [Traduit par la Rédaction] Mots-clés: triazapentadiényl, encombrement stérique, [beta]-dicétiminate, groupe 2, groupe 13, magnésium(I)., Introduction The fundamental and applied chemistry of compounds containing main group elements in very low oxidation states and (or) with very low coordination numbers has rapidly expanded in recent decades. [...]

The potassium salt of an extremely bulky β-diketiminate, [K(Ar*Nacnac)] (Ar*Nacnac, [(Ar*NCMe)2CH]−; Ar*, C6H2Me{C(H)Ph2}2-4,2,6) was reacted with either CaI2 or YbI2(THF)2, which afforded [(Ar*Nacnac)MI] (M = Ca or Yb). These are the first examples of structurally characterised, donor solvent-free, N-arene substituted β-diketiminato calcium and ytterbium complexes that incorporate a terminal iodide ligand. Reduction of [(Ar*Nacnac)CaI] with sodium metal gave a complex product mixture, from which a few crystals of the β-diketiminate C–H activated product, [{Ca(μ-Ar*Nacnac-H)}2], were obtained and crystallographically characterised. In an attempt to form a terminal ytterbium hydride compound, treatment of [(Ar*Nacnac)YbI] with K[HBEt3] gave a good yield of the contact ion pair compound [(Ar*Nacnac)Yb(HBEt3)]. The extremely bulky β-diketiminato calcium(ii) and ytterbium(ii) iodide complexes [(Ar*Nacnac)MI] (M = Ca or Yb) have been prepared. The reduction of [(Ar*Nacnac)CaI] with sodium metal yielded a ligand C–H activated product, while reaction of [(Ar*Nacnac)YbI] with K[HBEt3] gave an ytterbium(ii) borate contact ion pair (e.g. see picture). [ABSTRACT FROM AUTHOR]

The potassium salt of an extremely bulky β-diketiminate, [K(Ar*Nacnac)] (Ar*Nacnac, [(Ar*NCMe)2CH]−; Ar*, C6H2Me{C(H)Ph2}2-4,2,6) was reacted with either CaI2 or YbI2(THF)2, which afforded [(Ar*Nacnac)MI] (M = Ca or Yb). These are the first examples of structurally characterised, donor solvent-free, N-arene substituted β-diketiminato calcium and ytterbium complexes that incorporate a terminal iodide ligand. Reduction of [(Ar*Nacnac)CaI] with sodium metal gave a complex product mixture, from which a few crystals of the β-diketiminate C–H activated product, [{Ca(μ-Ar*Nacnac-H)}2], were obtained and crystallographically characterised. In an attempt to form a terminal ytterbium hydride compound, treatment of [(Ar*Nacnac)YbI] with K[HBEt3] gave a good yield of the contact ion pair compound [(Ar*Nacnac)Yb(HBEt3)]. The extremely bulky β-diketiminato calcium(ii) and ytterbium(ii) iodide complexes [(Ar*Nacnac)MI] (M = Ca or Yb) have been prepared. The reduction of [(Ar*Nacnac)CaI] with sodium metal yielded a ligand C–H activated product, while reaction of [(Ar*Nacnac)YbI] with K[HBEt3] gave an ytterbium(ii) borate contact ion pair (e.g. see picture). [ABSTRACT FROM AUTHOR]

The properties and spectroscopic data of the compounds are compared, and the synthesis and characterization of new halogen-substituted carbaalances, which are the key derivatives of carbaalane chemistry is reported. The result demonstrates the facile substitution of the hydridic atoms in Ph and CH2SiMe3 by the halides with different reagents.

The experimental charge density modeling of a magnesium dimer complex and subsequent topological analysis has disclosed the existence of a chemical bond between two central Mg atoms. The analysis of the molecular system by using the energy density, the source function, and density profiles along the entire bond path has shown the bond as one between two monovalent Mg atoms containing significant covalent character.

Halide abstraction is shown to be a good method for the generation of mononuclear cationic complexes containing gallium donor ligands. The ligand properties are compared with related ten valance electron systems such as [N.sub.2], CO and BF.

The synthesis and structural characterization of bridged 2,3,5,6-tetraphospha-1,4-dimethylidenecyclohexanes through reactions of unhindered phosphaalkyne P=CMe, with a digermene and two distannenes is reported. The findings from the reaction mechanism highlights significant differences in the reactivity of P=CMe compared to that of more sterically protected phosphaalkynes (P=CBu).

The preparation and structural characterization of a series of group 10 metal(0) complexes with four-membered Ga(I) and In(I) heterocycles is presented. Crystallographic and theoretical studies suggest that the covalent components of the Pt-Ga bonds in one homoleptic complex possess significant [pi] character.

The preparation of guanidinato- or amidinato-bridged diarsenes [A[s.sub.2]{[mu]-[(ArN).sub.2]-CR}.sub.2] [(Ar = [C.sub.6][H.sub.6]P[r.sub.2]-2,6; R = N([C.sub.6][H.sub.11]).sub.2], NP[r.sub.2] or Bu) are prepared by reduction of the corresponding As(III) precursors [C[l.sub.2]-As{[k.sup.2]-N,N'-(ArN).sub.2]CR}]. The findings from the theoretical studies suggest that the As-As bonds of the dimers have significant double-bond character the [sigma] and [pi] components of which are derived mainly from As p orbital overlaps.

The reaction of an anionic gallium(I) heterocyclic complex, [K(tmeda)][:Ga{[N(Ar)C(H).sub.2]]}, with a variety of heavier group 14 element(II) precursors is explored to investigate its analogies. The study highlighted the utility of the anionic gallium(I) heterocycle in potassium halide elimination reaction, and its reaction with bulky monomeric guanidinato group 14 halide complexes gave neutral complexes, [(Giso)EGa{[N(Ar)C(H)]2}], E = Ge or Sn, with covalent E-Ga bonds that are shorter than the E-Ga interactions seen in the aforementioned anionic complexes.

A series of organometallic compounds of group 13 metals supported by the sterically encumbered beta-diketiminate ligand containing hydrides, fluorides, chlorides, and bromide are synthesized and structurally characterized. The synthetic strategy applied utilizes halide metathesis and reduction of metal chlorides to the corresponding hydrides.

A class of weakly coordinating carbaalanates with the free anions [(AlH)(sub 8)(CCH(sub 2)t-Bu)(sub 6)](super 2-) and [(AlH)(sub 7)(AlNMe3)(CCH(sub 2)t-Bu)(sub 6)](super -) that are able to stabilize aluminum hydride cations such as [H(sub 2-)Al(NMe(sub 3))(sub 2)](super +) in [H2Al(NMe3)(sub 2)](sub 2-)[(AlH)(sub 8)(CCH(sub 2)t-Bu)(sub 6)] (3) is reported. Even though they are not stable toward protic reagents, their chemical inertness in general makes them as attractive target for future applications.