The demand for economical and environmentally benign catalysts important chemical transformations has recently initiated great efforts on nonprecious metal-catalyzed hydrosilylation reactions. special properties of cobalt enable the development diverse complex-based This paper reviews significant advances complex-catalyzed alkenes alkynes from early studies in 1960s until now, with objective providing readers status field underlying late 3d metal chemistry that is meaningful new catalyst...

The pursuit of single-molecule magnets (SMMs) with better performance urges new molecular design that can endow SMMs larger magnetic anisotropy. Here we report two-coordinate cobalt imido complexes featuring highly covalent Co═N cores exhibit slow relaxation magnetization under zero direct-current field a high effective barrier up to 413 cm–1, record for transition metal based SMMs. Two theoretical models were carried out investigate the anisotropy these complexes: single-ion model and Co–N...

Water oxidation is the key step in natural and artificial photosynthesis for solar-energy conversion. As this process thermodynamically unfavorable challenging from a kinetic point of view, development highly efficient catalysts with low energy cost subject fundamental significance. Herein, we report on iron-based films as water-oxidation catalysts. The can be quickly deposited onto electrodes Fe(II) ions acetate buffer at pH 7.0 by simple cyclic voltammetry. extremely iron loading critical...

Cobalt(II) complexes capable of catalyzing alkene hydrosilylation in the absence external activators are rarely known, and their activation mode has remained poorly understood. We present here that cobalt(II) amide complexes, [Co(N(SiMe3)2)2] its NHC adducts [(NHC)Co(N(SiMe3)2)2] (NHC = N-heterocyclic carbene), effective catalysts for alkenes with tertiary silanes. Mechanistic studies revealed amides can react hydrosilane to form cobalt(I) species, silylamide, hydrogen, which serves as entry...

The first single-ion magnet (SIM) [Co(IMes)₂][BPh₄] (IMes: 1,3-dimesitylimidazol-2-ylidene) with d⁸ electronic configuration has been found in two-coordinate Co(<sc>i</sc>)–NHC complexes.

The reaction of the cobalt(0) alkene complex [(IMes)Co(η(2):η(2)-dvtms)] (1) (IMes = 1,3-bis(1',3',5'-trimethylphenyl)imidazol-2-ylidene, dvtms divinyltetramethyldisiloxane) with 2 equiv DippN3 (Dipp 2,6-diisopropylphenyl) afforded cobalt(IV) imido [(IMes)Co(NDipp)2] (2), which could be oxidized by [Cp2Fe][BAr(F)4] (Ar(F) 3,5-di(trifluoromethyl)phenyl) to give cobalt(V) species [(IMes)Co(NDipp)2][BAr(F)4] (3). molecular structures all these complexes were established single-crystal X-ray...

Pep up your carbene catalyst: A sequential cobalt-mediated CH activation and silylation protocol has been developed for the preparation of novel silyl-donor-functionalized NHC complexes (see scheme; Mes=mesityl; R=H, Me, Ph). The resulting cobalt exhibited high activity selectivity as catalysts hydrosilylation olefins.

Late-transition-metal-based catalysts are widely used in N2 fixation reactions, but the reactivity of late-transition-metal complexes, besides iron has remained poorly understood as their complexes were thought to be labile and hard functionalize. By employing a monodentate N-heterocyclic carbene (NHC), 1,3-dicyclohexylimidazol-2-ylidene (ICy) ligand, cobalt(0)– cobalt(−1)–N2 [(ICy)3Co(N2)] (1) [(ICy)2Co(N2)2M]n (M = K, 2a; Rb, 2b; Cs, 2c), respectively, synthesized from stepwise reduction...

High-valent iron imido species are implicated as reactive intermediates in many iron-catalyzed transformations. However, isolable complexes of this type rare, and their reactivity is poorly understood. Herein, we report the synthesis, characterization, studies on novel three-coordinate iron(IV) bisimido with aminocarbene ligation. Using our recently reported synthetic method for [LFe(NDipp)2] (L = IMes, 1; Me2-cAAC, 2), four new complexes, [(IPr)Fe(NDipp)2] (3) [(Me2-cAAC)Fe(NR)2] (R Mes, 4;...

Abstract Transition‐metal‐catalyzed C—H bond amination reaction is an attractive method for the synthesis of amines. Fueled by growing interests in development economical and eco‐friendly catalysts organic transformations, there are great recent efforts on developing iron‐catalyzed reactions using azides, sulfonyl iminoiodanes as nitrene source. This review summarizes progress achieved field since 2011. The scope, synthetic utility catalytic reaction, current mechanistic understandings...

Metal-catalyzed hydrosilylation of alkynes is an ideal atom-economic method to prepare vinylsilanes that are useful reagents in the organic synthesis and silicone industry. Although great success has been made preparation β-vinylsilanes by metal-catalyzed reactions alkynes, reported for α-vinylsilanes suffer from narrow substrate scope and/or poor selectivity. Herein, we present selective Markovnikov terminal with tertiary silanes using a dicobalt carbonyl N-heterocyclic carbene (NHC)...

To investigate the effects of antihypertensive drugs on resistance artery structure, 17 essential hypertensive patients were randomly assigned to be treated with an angiotensin I-converting enzyme inhibitor, cilazapril, or a (β-blocker, atenolol, for 2 years. Blood pressure was well controlled throughout Before starting treatment, at end first year and second year, subjected gluteal subcutaneous fat biopsies, from which resistance-size arteries dissected studied. The media width lumen...

The all-ferrous [Fe4S4](0) state has been demonstrated in the fully reduced Fe protein of Azotobacter vinelandii nitrogenase complex. We seek synthetic analogues this more tractable than recently prepared but highly unstable cluster [Fe4S4(CN)4](4-) (Scott, Berlinguette, Holm, and Zhou, Proc. Natl. Acad. Sci. U.S.A. 2005, 102, 9741). N-heterocyclic carbene 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (Pr(i)2NHCMe2) found to stabilize clusters [Fe8S8(Pr(i)2NHCMe2)6] (4)...

The synthesis, structure, and reactivity of some organo-iron complexes with monodentate N-heterocyclic carbene (NHC) ligation were studied. Mononuclear ferrous [(IEt)2FeR2] (IEt = 2,5-diethyl-3,4-dimethylimidazol-1-ylidene, R Me (2a), CH2TMS (2b)) [(IPr)FeMes2] (3, IPr 2,5-diisopropyl-3,4-dimethylimidazol-1-ylidene) prepared in good yields via salt elimination reactions [(NHC)2FeCl2] (1) alkylation reagents. interaction 1 PhLi gave a mixture dinuclear [Cl(IEt)Fe(IEt′)2Fe(IEt)Cl] (4a)...

Intramolecular C(sp3)–H bond activation reactions mediated by low-valent cobalt, both Co(I) and Co(0), have been observed in the of three-coordinate cobalt complex [Co(IMes)2Cl] (IMes = 1,3-dimesitylimidazol-2-ylidene) with alkylation reagents sodium amalgam. The gave [Co(IMes)(IMes′)(N2)], featuring a metalated IMes′ anion, whereas one-electron-reduction reaction afforded [Co(IMes′)2]. Co(II) can react CO, isocyanide, diazo compound to furnish interesting complexes bearing functionalized...

The synthesis, structural characterization, and reactivity of the first two-coordinate cobalt complex featuring a metal-element multiple bond [(IPr)Co(NDmp)] (4; IPr=1,3-bis(2',6'-diisopropylphenyl)imidazole-2-ylidene; Dmp=2,6-dimesitylphenyl) is reported. Complex 4 was prepared from reaction [(IPr)Co(η(2) -vtms)2 ] (vtms=vinyltrimethylsilane) with DmpN3 . An X-ray diffraction study revealed its linear C-Co-N core short Co-N distance (1.691(6) Å). Spectroscopic characterization calculation...

The combined use of aminocarbene and divinyltetramethyldisiloxane (dvtms) as supporting ligands enables the access unprecedented low-coordinate iron(0) alkene compounds [L(n)Fe(η(2):η(2)-dvtms)] (L=N-heterocyclic carbene (NHC) or cyclic (alkyl)(amino)carbene (CAAC), n=1 2) from reactions FeCl2 with alkali-metal reducing agents, free ligands, dvtms. species deliver their {L(n)Fe(0)} fragments to perform redox Ph2SiH2, S8, Se, DippN3, furnishing novel aminocarbene-supported iron(IV) silylene,...

Selectivity control on the reaction of alkene with hydrosilane is a challenging task in development non-precious-metal-based hydrosilylation catalysts. While traditional way selectivity relies use different ligand type and/or metals, we report herein that cobalt(I) complexes bearing N-heterocyclic carbene ligands (NHCs) exhibit distinct catalyzing Ph2SiH2. [(IAd)(PPh3)CoCl] (IAd = 1,3-diadamantylimidazol-2-ylidene) an efficient catalyst for anti-Markovnikov monosubstituted alkenes....

Iron-catalyzed cross-coupling of nonactivated primary alkyl fluorides with aryl Grignard reagents has been achieved by using the low-coordinate dinuclear iron complex [(IPr2Me2)Fe(μ2-NDipp)2Fe(IPr2Me2)] as catalyst. This iron-catalyzed C(sp3)–F bond arylation reaction is applicable to a variety and fluorides. The product pattern suggests involvement radical-type mechanism for its C–F scission step.

Transition-metal alkylidenes are important reactive organometallic intermediates, and our current knowledge on them has been mainly restricted to those with closed-shell electronic configurations. In this study, we present an exploration open-shell iron a weak-field tripodal amido-phosphine-amido ligand. We found that high-spin (amido-phosphine-amido)iron(II) complex can react (p-tolyl)2CN2 afford (amido-ylide-amido)iron(II) complex, 2, which could transfer its alkylidene moiety variety of...

Comprehensive Summary Hydrogermylation of alkenes and alkynes provides a straightforward synthetic route to organogermanium compounds that have been found applications in organic synthesis, medicinal chemistry, material science. This paper reviews the advances transition‐metal‐catalyzed hydrogermylation unsaturated carbon‐carbon bonds, including alkenes, alkynes, dienes, allenes, with objective providing readers status field. Progress, problems, perspectives this field are discussed.