Application of Bis(amido)alkyl Magnesiates toward the Synthesis of Molecular Rubidium and Cesium Hydrido-magnesiates.

Rubidium and cesium are the least studied naturally occurring s-block metals in organometallic chemistry but are in plentiful supply from a sustainability viewpoint as highlighted in the periodic table of natural elements published by the European Chemical Society. This underdevelopment reflects the phenomenal success of organometallic compounds of lithium, sodium, and potassium, but interest in heavier congeners has started to grow. Here, the synthesis and structures of rubidium and cesium bis(amido)alkyl magnesiates [(AM)MgN'alkyl], where N' is the simple heteroamide N(SiMe)(Dipp), and alkyl is Bu or CHSiMe, are reported.

A combined gas-phase dissociative ionization, dissociative electron attachment and deposition study on the potential FEBID precursor [Au(CH)Cl].

Motivated by the potential of focused-electron-beam-induced deposition (FEBID) in the fabrication of functional gold nanostructures for application in plasmonic and detector technology, we conducted a comprehensive study on [Au(CH)Cl] as a potential precursor for such depositions. Fundamental electron-induced dissociation processes were studied under single collision conditions, and the composition and morphology of FEBID deposits fabricated in an ultrahigh-vacuum (UHV) chamber were explored on different surfaces and at varied beam currents. In the gas phase, dissociative ionization was found to lead to significant carbon loss from this precursor, and about 50% of the chlorine was on average removed per dissociative ionization incident.

Three Oxidative Addition Routes of Alkali Metal Aluminyls to Dihydridoaluminates and Reactivity with CO.

Three distinct routes are reported to the soluble, dihydridoaluminate compounds, AM[Al(NON )(H) ] (AM=Li, Na, K, Rb, Cs; [NON ] =[O(SiMe NDipp) ] ; Dipp=2,6-iPr C H ) starting from the alkali metal aluminyls, AM[Al(NON )]. Direct H hydrogenation of the heavier analogues (AM=Rb, Cs) produced the first examples of structurally characterized rubidium and caesium dihydridoaluminates, although harsh conditions were required for complete conversion. Using 1,4-cyclohexadiene (1,4-CHD) as an alternative hydrogen source in transfer hydrogenation reactions provided a lower energy pathway to the full series of products for AM=Li-Cs.

Synthesis, Characterization, and Structural Analysis of [Al(NON)(H)(SiHPh)] ( = Li, Na, K, Rb, Cs) Compounds, Made Via Oxidative Addition of Phenylsilane to Alkali Metal Aluminyls.

We report the oxidative addition of phenylsilane to the complete series of alkali metal () aluminyls [{Al(NON)}] ( = Li, Na, K, Rb, and Cs). Crystalline products () have been isolated as ether or THF adducts, [(L)][Al(NON)(H)(SiHPh)] ( = Li, Na, K, Rb, L = EtO, = 1; = Cs, L = THF, = 2). Further to this series, the novel rubidium rubidiate, [{Rb(THF)}(Rb{Al(NON)(H)(SiHPh)})] [Rb{Al(NON)(H)(SiHPh)}], was isolated during an attempted recrystallization of Rb[Al(NON)(H)(SiHPh)] from a hexane/THF mixture.

On the Electron-Induced Reactions of (CH)AuP(CH): A Combined UHV Surface Science and Gas-Phase Study.

Focused-electron-beam-induced deposition (FEBID) is a powerful nanopatterning technique where electrons trigger the local dissociation of precursor molecules, leaving a deposit of non-volatile dissociation products. The fabrication of high-purity gold deposits via FEBID has significant potential to expand the scope of this method. For this, gold precursors that are stable under ambient conditions but fragment selectively under electron exposure are essential.

Heavy Alkali Metal Manganate Complexes: Synthesis, Structures and Solvent-Induced Dissociation Effects.

Rare examples of heavier alkali metal manganates [{(AM)Mn(CH SiMe )(N ) } ] (AM=K, Rb, or Cs) [N =N(SiMe )(Dipp), where Dipp=2,6-iPr -C H ] have been synthesised with the Rb and Cs examples crystallographically characterised. These heaviest manganates crystallise as polymeric zig-zag chains propagated by AM⋅⋅⋅π-arene interactions. Key to their preparation is to avoid Lewis base donor solvents.

Calcium catalyzed enantioselective intramolecular alkene hydroamination with chiral -symmetric bis-amide ligands.

The chiral building block (R)-(+)-2,2'-diamino-1,1'-binaphthyl, (R)-BINAM, which is often used as backbone in privileged enantioselective catalysts, was converted to a series of N-substituted proligands R1-H2 (R = CH2tBu, C(H)Ph2, PPh2, dibenzosuberane, 8-quinoline). After double deprotonation with strong Mg or Ca bases, a series of alkaline earth (Ae) metal catalysts R1-Ae·(THF)n was obtained. Crystal structures of these C2-symmetric catalysts have been analyzed by quadrant models which show that the ligands with C(H)Ph2, dibenzosuberane and 8-quinoline substituents should give the best steric discrimination for the enantioselective intramolecular alkene hydroamination (IAH) of the aminoalkenes H2C[double bond, length as m-dash]CHCH2CR'2CH2NH2 (CR'2 = CPh2, CCy or CMe2).

Insights into LiAlH Catalyzed Imine Hydrogenation.

Commercial LiAlH can be used in catalytic quantities in the hydrogenation of imines to amines with H . Combined experimental and theoretical investigations give deeper insight in the mechanism and identifies the most likely catalytic cycle. Activity is lost when Li in LiAlH is exchanged for Na or K.

Magnesium Cyanide or Isocyanide?

Preference for the binding mode of the CN ligand to Mg (Mg-CN vs. Mg-NC) is investigated. A monomeric Mg complex with a terminal CN ligand was prepared using the dipyrromethene ligand DPM which successfully blocks dimerization.

Lewis acidic alkaline earth metal complexes with a perfluorinated diphenylamide ligand.

Alkaline earth metal (Ae) chemistry with the anion [N(CF)] has been explored. Deprotonation of the amine (CF)NH, abbreviated in here as NH, with 0.5 equivalent of AeN'' (N'' = N(SiMe)) is fast and gave, dependent on the solvent, the complexes AeN, AeN·(THF) and AeN·(EtO) (Ae = Mg, Ca, Sr).

Low Valent Magnesium Chemistry with a Super Bulky β-Diketiminate Ligand.

The steric bulk of the well-known BDI ligand (CH[C(CH )N-DIPP] , DIPP=2,6-diisopropylphenyl) was increased by replacing isopropyl for isopentyl groups. This very bulky BDI ligand could not stabilize the radical species ( BDI)Mg : reduction of ( BDI)MgI with Na gave ( BDI) Mg with a rather long Mg-Mg bond of 3.0513(8) Å.

LiAlH : From Stoichiometric Reduction to Imine Hydrogenation Catalysis.

Imine-to-amine conversion with catalytic instead of stoichiometric quantities of LiAlH is demonstrated (85 °C, catalyst loading≥2.5 mol %, pressure≥1 bar). The effects of temperature, pressure, solvent, and catalyst modifications, as well as the substrate scope are discussed.

Simple Access to the Heaviest Alkaline Earth Metal Hydride: A Strongly Reducing Hydrocarbon-Soluble Barium Hydride Cluster.

Reaction of Ba[N(SiMe ) ] with PhSiH in toluene gave simple access to the unique Ba hydride cluster Ba H [N(SiMe ) ] that can be described as a square pyramid spanned by five Ba ions with two flanking BaH[N(SiMe ) ] units. This heptanuclear cluster is well soluble in aromatic solvents, and the hydride H NMR signals and coupling pattern suggests that the structure is stable in solution. At 95 °C, no coalescence of hydride signals is observed but the cluster slowly decomposes to undefined barium hydride species.

Calcium stilbene complexes: structures and dual reactivity.

Addition of a calcium hydride complex to diphenylacetylene gave a complex in which the stilbene dianion symmetrically bridges two Ca ions. DFT calculations discuss the effect of the metal stilbene coordination. The stilbene complex reacts as a base (with H) or an electron donor (with I) and catalyzes the reduction of diphenylacetylene.

A Simple Route to Calcium and Strontium Hydride Clusters.

The first strontium hydride complex has been obtained by simply treating Sr[N(SiMe ) ] with PhSiH in the presence of PMDTA. The Sr complex Sr H [N(SiMe ) ] ⋅(PMDTA) crystallizes as an "inverse cryptand": an interstitial H is surrounded by a Sr H cage decorated with amide and PMDTA ligands. The analogous Ca complex could also be obtained and both retain their solid-state structures in solution: H NMR spectra in C D show two doublets and one nonet (4:4:1).

Bora-amidinate as a cooperative ligand in group 2 metal catalysis.

Syntheses and crystal structures of the monomeric bora-amidinate (bam) complexes NBN-Mg·(THF) and NBN-Ca·(THF) are presented; NBN = HB[N(2,6-iPr-CH)]. The simplicity of their H NMR spectra in THF-d suggest that their monomeric solid state structures are retained in solution. NBN-Mg·(THF) in CD, however, is in equilibrium with a dimeric species.

β-Diketiminate calcium hydride complexes: the importance of solvent effects.

A series of (DIPPnacnac)CaN(SiMe)·S complexes (DIPPnacnac = HC[C(Me)N(2,6-iPr-CH)]; S = solvent) could be obtained by the addition of S = THF, DME or N-Me-morpholine (Morph) to (DIPPnacnac)CaN(SiMe)·OEt or (DIPPnacnac)CaN(SiMe). Crystal structures for complexes with S = DME and Morph are compared to literature-known structures with S = none, THF or EtO. Bulkier and weaker Lewis bases like the tertiary amines EtN, TMEDA and DABCO did not interact with (DIPPnacnac)CaN(SiMe).