Stabilisation of a Strontium Hydride with a Monodentate Carbazolyl Ligand and its Reactivity.

The molecular strontium hydride 2 [(Cbz)SrH(L)] (L=benzene, toluene) was isolated and stabilized by employing a sterically demanding carbazole ligand (Cbz=1,8-bis(3,5-ditertbutylphenyl)-3,6-ditertbutylcarbazolyl). Compound 2 was synthesized via phenylsilane metathesis with the corresponding amide (Cbz)SrN(SiMe) and characterized by H NMR, XRD and vibrational spectroscopy methods. We further investigated the stoichiometric reactivity of 2 towards carbon monoxide, azobenzene and trimethylsilylacetylene, showing three distinct reactivity pathways: addition, reduction and deprotonation.

CO reduction by calcium and ytterbium hydride complexes with a bulky monodentate carbazolyl ligand.

The bulky monodentate carbazolyl ligand 1,8-bis(3,5-dibutylphenyl)-3,6-dibutylcarbazole (Cbz) was employed in the synthesis of monomeric heteroleptic amido carbazolyl complexes of Ca and Yb. For both central metal atoms, dimeric hydride complexes [(Cbz)Ca(benzene)H], [(Cbz)Ca(THF)H], [(Cbz)Yb(benzene)H] and [(Cbz)Yb(THF)H] were obtained, which show remarkably poor solubility in organic solvents. The characteristic hydride H NMR resonance of [(Cbz)Ca(benzene)H] was observed at 2.

Silylenes with a Small Chalcogenide Substituent: Tuning Frontier Orbital Energies from O to Te.

The general synthesis of heteroleptic acyclic silylenes with a bulky carbazolyl substituent (Cbz) is detailed and a series of compounds with a chalcogenide substituent of the type [(Cbz)SiER] (ER=OBu, SEt, SePh, TePh) is reported. With the bulky carbazolyl substituent present, the chalcogenide moiety can be very small, as is shown by incorporating groups as small as ethyl, phenyl or tert-butyl. For the first time, the electronic properties of the silylene can be tuned along a complete series of chalcogenide substituents.

Synthesis and Reactivity of Base-Stabilized and Base-Free Silaimidoyl Bromides.

The reactivity of the base-free bromosilylene CbzSiBr (Cbz = 1,8-bis(3,5-di-butylphenyl)-3,6-di--butylcarbazolyl) toward carbodiimides and azides was studied in order to generate base-stabilized and base-free silaimidoyl bromides, respectively. The steric bulk of carbodiimides and azides allows control over the reactivity. While with small substituents such as -butyl or adamantyl, the reactions cannot be stopped at the Si═N stage, with large substituents, they lead to C-H activation in the product.

Photolysis of Phosphaketenyltetrylenes with a Carbazolyl Substituent.

Phosphaketenes of divalent group 14 compounds can potentially serve as precursors for the synthesis of heavy multiple-bond systems. We have employed the Cbz substituent ( Cbz=1,8-bis(3,5-ditertbutylphenyl)-3,6-ditertbutylcarbazolyl) to prepare such phosphaketenyltetrylenes [( Cbz)EPCO] (E=Ge, Sn, Pb). While the phosphaketenyltetrylenes are stable at ambient conditions, they can be readily decarbonylated photolytically.

A Barium Complex of the Silanide SiH: Hydride Surrogate and Source of Silicon.

The silanide SiH is an archetypical anion. Its metathesis chemistry is, however, still underdeveloped. We have conveniently prepared the barium silanide complex [(Cbz)BaSiH] with a bulky carbazolide ligand by reaction of the corresponding barium amide with phenyl silane in a good yield.

Fe-Gd Ferromagnetic Cyclic Coordination Cluster [FeGd(teaH)(N)(HO)] with Magnetic Anisotropy─Theory and Experiment.

The synthesis, structural, and magnetic characterization of [FeLn(teaH)(N)(HO)] (Ln = Gd and Y) and the previously reported isostructural Dy analogue are discussed. The commonly held belief that both Fe and Gd can be regarded as isotropic ions is shown to be an oversimplification. This conclusion is derived from the magnetic data for the Y analogue in terms of the zero-field splitting seen for Fe and from the fact that the magnetic data for the new Gd analogue can only be fit employing an additional anisotropy term for the Gd ions.

Reactivity of Pt(0) bromosilylene complexes towards ethylene.

The base-free carbazolyl bromosilylene RSiBr (R = 1,8-bis(3,5-di--butyl-phenyl)-3,6-di--butyl-carbazolyl) reacts with (η-CH)Pt(PPh) and Pt(PCy) to form platinasilacyclobutane R(Br)Si(CH)Pt(PPh) (1) and silylene platinum complex R(Br)SiPt(PCy) (2), respectively. When silylene complex 2 is treated with CH, the six-membered metallasilacycle R(Br)Si(CH)Pt(PCy) (3) is obtained. All compounds are characterised by XRD and multinuclear NMR spectroscopy.

Control over Selectivity in Alkene Hydrosilylation Catalyzed by Cobalt(III) Hydride Complexes.

Two new bisphosphine [PCP] pincer cobalt(III) hydrides, [(L)Co(PMe)(H)(Cl)] (, = 2,6-((PhP)(Et)N)CH) and [(L)Co(PMe)(H)(Cl)] (, = 2,6-((PrP)(Et)N)CH), as well as one new bissilylene [SiCSi] pincer cobalt(III) hydride, [(L)Co(PMe)(H)(Cl)] (, = 1,3-((PhC(BuN)Si)(Et)N)CH), were synthesized by reaction of the corresponding protic [PCP] or [SiCSi] pincer ligands , and with CoCl(PMe). Despite the similarities in the ligand scaffolds, the three cobalt(III) hydrides show remarkably different performance as catalysts in alkene hydrosilylation. Among the PCP pincer complexes, has higher catalytic activity than complex , and both catalysts afford -Markovnikov selectivity for both aliphatic and aromatic alkenes.

Impact of synthesis conditions on the morphology and crystal structure of tungsten nitride nanomaterials.

Nanocrystalline tungsten nitride (WN ) aggregates and nanosheets are synthesized with a new alkylamine-based synthesis strategy for potential applications in nanoelectronics and catalysis. These applications preferentially require crystalline materials with controlled morphology, which has been rarely demonstrated for WN nanomaterials in the past. In the synthesis approach presented in this work, the morphology of nanoscale WN is controlled by long-chained amines that form lyotropic or lamellar phases depending on the surfactant concentration.

Structural Properties and ELNES of Polycrystalline and Nanoporous MgN.

Nanoporous, high-purity magnesium nitride (Mg3N2) was synthesized with a liquid ammonia-based process, for potential applications in optoelectronics, gas separation and catalysis, since these applications require high material purity and crystallinity, which has seldom been demonstrated in the past. One way to evaluate the degree of crystalline near-range order and atomic environment is electron energy-loss spectroscopy (EELS) in a transmission electron microscope. However, there are hardly any data on Mg3N2, which makes identification of electron energy-loss near-edge structure (ELNES) features difficult.

Synthesis and Thermal Decomposition of Heavy Tetrylenes Bearing N-Aminocarbazolyl Substituents.

The synthesis of the N-aminocarbazole R-NH (2) is reported. Subsequent reaction with bis[bis(trimethylsilyl)amido]tetrylenes E[N(SiMe ) ] (E=Ge, Sn, or Pb) allowed the isolation of formal hydrazidotetrylene derivatives, R-N(H)EN(SiMe ) (3) that includes the first example of a hydrazidoplumbylene to date. Thermal decomposition of these compounds resulted in the elimination of "NH" and afforded the tetrylenes R-EN(SiMe ) (4).

Pseudo-One-Coordinate Tetrylenium Salts Bearing a Bulky Carbazolyl Substituent.

Syntheses of a bulky carbazole-based substituent, the parent 1,8-bis(3,5-di-tert-butylphenyl)-3,6-di-tert-butyl-carbazole (R-H) and a series of chlorotetrylenes, RECl (E=Ge, Sn, Pb), are described. Detailed analysis of the properties of the carbazole-based substituent revealed that it features flexible high bulkiness and electronic non-innocence, which may make it suitable for many applications in both main-group and transition-metal chemistry. To further showcase the employability of the novel substituent, the chlorotetrylenes were subjected to halide abstraction reactions, affording the corresponding tetrylenium salts [RE][Al(OC F ) ] (E=Ge, Sn, Pb) as strongly coloured compounds.

Spatially-Resolved Multiple Metallopolymer Surfaces by Photolithography.

A tetrazole-based photoligation protocol for the spatially-resolved encoding of various defined metallopolymers onto solid surfaces is introduced. By using this approach, fabrication of bi- and trifunctional metallopolymer surfaces with different metal combinations were achieved. Specifically, α-ω-functional copolymers containing bipyridine as well as triphenylphosphine ligands were synthesized through reversible addition-fragmentation chain transfer (RAFT) polymerization, and subsequently metal loaded to afford metallopolymers of the widely-used metals gold, palladium, and platinum.