Dalton Transactions

doi: 10.1039/b813088bpmid: N/A

doi: 10.1039/b813089mpmid: N/A

Arnold, John

doi: 10.1039/b812066hpmid: 18698434

Rivard, Eric; Power, Philip P.

doi: 10.1039/b801400kpmid: 18698435

This Perspective discusses the synthesis and reactivity of low valent Group 14 hydrides of germanium and tin. The use of hindered terphenyl ligands has facilitated the isolation of a number of unusual new main group hydride structural types (each predicted by computational work), and has culminated in the use of these species as precursors to new cluster archetypes.

Schnöckel, Hansgeorg

doi: 10.1039/b718784jpmid: 18698436

The renaissance of Al and Ga cluster chemistry is presented in three steps: on the grounds of boron hydride chemistry and the Wade concept, the first step starts in the early nineties of the last century with the formation of single Al–Al and Ga–Ga bonds in molecular entities, obtained by different synthetic approaches. The special method via reaction of high-temperature molecules like AlCl and its disproportionation to Al metal and AlX3 leads to the second step which started about 10 years ago: the formation of nanoscaled metalloid Al and Ga clusters as intermediates on the way to the metal. Based on the structure of several recent examples, bonding is discussed with respect to the structure of the elements and the generation of naked metal atom clusters. After discussion of the individual metalloid clusters including experiments of the gaseous species and discussion about the jellium model, the third step and main part of this review starts only a few years ago. This latest period hardly can be called a renaissance period as, so far, interactions of nanoscaled metal atom clusters in a perfect 1-, 2- or 3-dimensional arrangement of a crystal have never been investigated before. The most remarkable result in this perspective is the superconducting behaviour of a Ga84 cluster compound in the crystalline state which had never been observed in metal atom clusters before. However, these experiments show that superconductivity is only observed if the clusters in the crystal are perfectly orientated: as a cluster arrangement of this type can hardly be fabricated by physical methods, these results, which have been predicted by theory, may be called a disillusionment for nanosciences; for chemistry, however, these conclusions pose a challenge.

Blackstone, Vivienne; Presa Soto, Alejandro; Manners, Ian

doi: 10.1039/b719361kpmid: 18698437

This Perspective discusses the development of new routes to polyphosphazenes, [R2PN]n, that occur at ambient temperature and, in some cases, allow molecular weight control and access to narrow molecular weight distributions and block copolymers. For example, the room temperature silyl-carborane initiated ring-opening polymerisation of (NPCl2)3 is described together with chain growth condensation polymerisations of phosphoranimines Cl3PNSiMe3 and BrMePhPNSiMe3. Recent works on donor-stabilised cationic phosphoranimines are also discussed.

Scheer, Manfred

doi: 10.1039/b718179ppmid: 18698438

A survey of the contemporary challenges of the field of unsubstituted group 15 element ligand complexes (excluding N) is given. The focus of the article is on the coordination chemistry behaviour of such E ligand complexes. This field is subdivided into two areas of reactivity: E ligand complexes with (i) noncoordinated Lewis-acidic cations and (ii) Lewis-acidic coordination compounds containing at least one permanently coordinating ligand. In the latter case, insoluble 1D and 2D polymers respectively are obtained; however, under special conditions soluble, spherical, fullerene-like giant molecules are formed. These nano-sized molecules are up to 2.4 nm in diameter and are able to encapsulate small molecules in their holes. In contrast, the first-mentioned field uses weakly coordinating anions to obtain readily soluble di- and polycationic products. These show depolymerisation tendencies in solution under the formation of oligomer–monomer equilibria and thus reveal dynamic supramolecular aggregation processes.

Yang, Peidong

doi: 10.1039/b801440jpmid: 18698439

This article provides a short overview of the current status of the silicon nanowire research including its synthetic chemistry and physical property characterization, with examples drawn mainly from the author's lab.

Zhang, Yun; Reed, Christopher A.

doi: 10.1039/b803304hpmid: 18698440

The long sought hexamethylhydrazinium(2+) dication, Me3N–NMe32+, calculationally unstable towards “coulombic explosion” because of formal positive charges on adjacent N atoms, can be synthesized and isolated as a CHB11Cl11− carborane salt.

Jones, Cameron; Mills, David P.; Rose, Richard P.; Stasch, Andreas

doi: 10.1039/b715895epmid: 18698441

Reactions of the anionic gallium(i) heterocycle, [:Ga{[N(Ar)C(H)]2}]− (Ar = C6H3Pri2-2,6), with a variety of mono- and bidentate phosphine, tmeda and 1,5-cyclooctadiene (COD) complexes of group 10 metal dichlorides are reported. In most cases, salt elimination occurs, affording either mono(gallyl) complexes, trans-[MCl{Ga{[N(Ar)C(H)]2}}(PEt3)2] (M = Ni or Pd) and cis-[PtCl{Ga{[N(Ar)C(H)]2}}(L)] (L = R2PCH2CH2PR2, R = Ph (dppe) or cyclohexyl (dcpe)), or bis(gallyl) complexes, trans-[M{Ga{[N(Ar)C(H)]2}}2(PEt3)2] (M = Ni, Pd or Pt), cis-[Pt{Ga{[N(Ar)C(H)]2}}2(PEt3)2], cis-[M{Ga{[N(Ar)C(H)]2}}2(L)] (M = Ni, Pd or Pt; L = dppe, Ph2CH2PPh2 (dppm), tmeda or COD). The crystallographic and spectroscopic data for the complexes show that the trans-influence of the gallium(i) heterocycle lies in the series, B(OR)2 > H− > PR3 ∼ [:Ga{[N(Ar)C(H)]2}]− > Cl−. Comparisons between the reactivity of one complex, [Pt{Ga{[N(Ar)C(H)]2}}2(dppe)], with that of closely related platinum bis(boryl) complexes indicate that the gallyl complex is not effective for the catalytic or stoichiometric gallylation of alkenes or alkynes. The phosphaalkyne, ButCP, does, however, insert into one gallyl ligand of the complex, leading to the novel, crystallographically characterised P,N-gallyl complex, [Pt{Ga{[N(Ar)C(H)]2}}{Ga{PC(But)C(H)[N(Ar)]C(H)N(Ar)}}(dppe)]. An investigation into the mechanism of this insertion reaction has been undertaken.