N_2 Functionalization at Iron Metallaboratranes

The reactivity of the anionic dinitrogen complex [(TPB)Fe(N_2)]^− (TPB = tris[2-(diisopropylphosphino)phenyl]borane) toward silicon electrophiles has been examined. [(TPB)Fe(N_2)]^− reacts with trimethylsilyl chloride to yield the silyldiazenido complex (TPB)Fe(NNSiMe_3), which is reduced by Na/Hg in THF to yield the corresponding sodium-bound anion [(TPB)Fe(NNSiMe_3)]Na(THF). The use of 1,2-bis(chlorodimethylsilyl)ethane in the presence of excess Na/Hg results in the disilylation of the bound N_2 molecule to yield the disilylhydrazido(2−) complex (TPB)Fe≡NR (R = 2,2,5,5-tetramethyl-1-aza-2,5-disilacyclopentyl). One of the phosphine arms of TPB in (TPB)Fe≡NR can be substituted by CO or ^tBuNC to yield crystalline adducts (TPB)(L)Fe≡NR (L = CO, ^tBuNC). The N–N bond in (TPB)(^tBuNC)Fe≡NR is cleaved upon standing at room temperature to yield a phosphoraniminato/disilylamido iron(II) complex. The flexibility of the Fe–B linkage is thought to play a key role in these transformations of Fe-bound dinitrogen

Peer-to-peer and community-based markets: A comprehensive review

The advent of more proactive consumers, the so-called "prosumers", with production and storage capabilities, is empowering the consumers and bringing new opportunities and challenges to the operation of power systems in a market environment. Recently, a novel proposal for the design and operation of electricity markets has emerged: these so-called peer-to-peer (P2P) electricity markets conceptually allow the prosumers to directly share their electrical energy and investment. Such P2P markets rely on a consumer-centric and bottom-up perspective by giving the opportunity to consumers to freely choose the way they are to source their electric energy. A community can also be formed by prosumers who want to collaborate, or in terms of operational energy management. This paper contributes with an overview of these new P2P markets that starts with the motivation, challenges, market designs moving to the potential future developments in this field, providing recommendations while considering a test-case

A Polar Copper−Boron One-Electron σ‑Bond

Virtually all chemical bonds consist of one or several pairs of electrons shared by two atoms. Examples of σ-bonds made of a single electron delocalized over two neighboring atoms were until recently found only in gas-phase cations such as H_2^+ and Li_2^+ and in highly unstable species generated in solid matrices. Only in the past decade was bona fide one-electron bonding observed for molecules in fluid solution. Here we report the isolation and structural characterization of a thermally stable compound featuring a Cu–B one-electron bond, as well as its oxidized (nonbonded) and reduced (two-electrons-bonded) congeners. This triad provides an excellent opportunity to study the degree of σ-bonding in a metalloboratrane as a function of electron count

Conversion of Fe−NH_2 to Fe−N_2 with release of NH_3

Tris(phosphine)borane ligated Fe(I) centers featuring N_2H_4, NH_3, NH_2, and OH ligands are described. Conversion of Fe–NH_2 to Fe–NH_3^+ by the addition of acid, and subsequent reductive release of NH_3 to generate Fe–N_2, is demonstrated. This sequence models the final steps of proposed Fe–mediated nitrogen fixation pathways. The five-coordinate trigonal bipyramidal complexes described are unusual in that they adopt S = 3/2 ground states and are prepared from a four-coordinate, S = 3/2 trigonal pyramidal precursor

Функциональная нагрузка обобщающе-выделительных местоимений в предложении

A range of silanes was synthesized by the reaction of HSiCl3 with iminopyrrole derivatives in the presence of NEt3. In certain cases, intramolecular hydrosilylation converts the imine ligand into an amino substituent. This reaction is inhibited by factors such as electron-donating substitution on Si and steric bulk. The monosubstituted (DippIMP)SiHMeCl (DippIMP=2-[N-(2,6-diisopropylphenyl)iminomethyl]pyrrolide), is stable towards hydrosilylation, but slow hydrosilylation is observed for (DippIMP)SiHCl2. Reaction of two equivalents of DippIMPH with HSiCl3 results in the hydrosilylation product (DippAMP)(DippIMP)SiCl (DippAMP=2-[N-(2,6-diisopropylphenyl)aminomethylene]pyrrolide), but the trisubsitituted (DippIMP)3SiH is stable. Monitoring the hydrosilylation reaction of (DippIMP)SiHCl2 reveals a reactive pathway involving ligand redistribution reactions to form the disubstituted (DippAMP)(DippIMP)SiCl as an intermediate. The reaction is strongly accelerated in the presence of chloride anions

Rhenium-Catalyzed Dehydration and Deoxydehydration of Alcohols and Polyols: Opportunities for the Formation of Olefins from Biomass

In view of the depletion of petroleum oils, new synthetic routes for the sustainable production of chemicals, fuels, and energy from renewable biomass sources are currently widely investigated. In particular, nonedible sugars and polyols are promising starting materials to produce olefins by dehydration, deoxygenation, or deoxydehydration (DODH) of these poly vicinal alcohols. In this perspective, we highlight the recent evolution of rhenium-catalyzed dehydration and DODH of biomass-derived alcohols and polyols to obtain olefins. Improving over the classical acid-catalyzed dehydration reaction, rhenium-mediated systems are very selective and more active to provide high yields of olefin products, but dehydration alone cannot be used to fully defunctionalize sugars. This issue is addressed by a growing research effort in the field of Re-catalyzed DODH, which allows complete dehydroxylation to form olefins in high yield. Recent developments in this field include the development of new molecular rhenium catalysts, the application of cheaper and more available reductants, and a growing mechanistic understanding owing to both experimental and computational studies. Finally, recent efforts to move beyond rhenium toward cheaper metals (Mo, V) are discussed