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Previous mass spectrometric (MS) studies demonstrated that singly charged hydration clusters of manganese ions [Mn-(H2O)n]+ were, on one hand, highly reactive toward intracluster water insertion but, on the other hand, inert toward nitrous oxide activation. This contrast in reactivity has been rationalized by our present theoretical investigation for the interconversion between the pristine Mn-(I) monovalent form as a monatomic ion in [MnI(H2O)n]+ and the oxidized Mn-(III) trivalent form as a hydride–hydroxide in [HMnIIIOH-(H2O)n−1], as well as their reactivity toward nitrous oxide activation. Our theoretical interpretations are supported with quantum chemical calculations based on density functional theory (DFT), performed systematically for the cluster-size range of n = 1 – 12. Our DFT results show that water insertion is kinetically and thermodynamically favorable for n ≥ 8, suggesting [HMnIIIOH-(H2O)n−1]+ is the predominant form, as observed in previous MS experiments. While [MnI(H2O)n]+ is capable of N2O reduction, the process of which is highly exothermic, similar reactions are unfavorable with [HMnIIIOH-(H2O)n−1]+, which can only form weakly bound adducts with N2O. This work demonstrates the masking effect of water molecules over the high reactivity of the hydrated Mn-(I) center and sheds light on the potential roles of water in transition metal systems. [ABSTRACT FROM AUTHOR]

We demonstrate that regioselective aryl transfer to the nucleophile occurs rapidly under mild conditions via reductive elimination and show that regioselectivity is primarily governed by steric factors imparted by ortho substituents on the recipient ring. Computational modeling and x‐ray crystallography confirm that the recipient aryl ring is positioned in the equatorial coordination site and oriented orthogonally to the axial X−Bi−Ph bond (X=nucleophile) in a trigonal bipyramidal structure. The orientation of the ortho‐substituted aryl ring allows the appropriate orbital to overlap between its ipso carbon and nucleophile, which enhances the rate of aryl transfer to the nucleophile and dictates the regioselective reductive elimination from Bi(V) compounds. This level of stereoelectronic control results in significantly enhanced reaction rate and selectivity and creates an opportunity to rationally design ligand systems for selective aryl transfer reactions. [ABSTRACT FROM AUTHOR]

[Display omitted] The cross-coupling reaction of chlorobenzene and phenylboronic acid, catalyzed by the [R 3 Si–IPr]Pd0 species (generated upon activation of {[R 3 Si–IPr]Pd(173-allyl)Cl} pre-catalyst complexes) in the presence of hydroxide ion as a base, was studied in details by the quantum chemical calculations. Each step of the whole process, including pre- catalyst activation, oxidative addition, transmetalation and reductive elimination, were computationally probed to locate reaction intermediates and transition states along the reaction coordinate. Accordingly, transmetalation was found to be a limiting step of the catalytic cycle (involving oxidative addition, transmetalation and reductive elimination), whereas pre-catalyst activation was revealed as a limiting step of the whole catalytic process. [ABSTRACT FROM AUTHOR]

The widely used nickel catalysis for carbon‐heteroatom cross‐coupling reactions often requires high energy to achieve reductive elimination on NiII complexes. To overcome the energy barrier of reductive elimination, the NiII complexes often transform to NiIII facile reductive elimination via single electron transfer in photochemistry. Energy transfer to form the excited‐state NiII complexes is feasible as well for carbon‐heteroatom couplings in nickel catalysis. This Review is focused on the discussion about the variant nickel(II) complexes as the precatalysts to forge diverse carbon‐heteroatom bonds under visible‐light irradiation in the absence of exogenous photocatalysts. Summary of photoactive nickel catalysis aims to promote the development of cheap, abundant metals catalyzed carbon‐heteroatom couplings for efficient preparation of highly valuable chemicals. [ABSTRACT FROM AUTHOR]

In this joint theoretical and experimental study, an analysis of weak interligand noncovalent interactions within Co(IV) [Cp*Co(phpy)X]+ cobaltacycles (phpy = 2-phenylenepyridine, κ C , N ) was carried out by using the independent gradient model/intrinsic bond strength index (IGM/IBSI) method to evaluate the dependency of the catalytically desired reductive elimination pathway (RE) on the nature of the X ligand. It is shown that the barrier for activation of the RE pathway correlates directly with the IBSI of the X-to-carbanionic chelate's carbon. This correlation suggests that in silico prediction of which X ligand is more prone to operate an efficient Cp*Co-catalyzed directed X-functionalization of an aromatic C–H bond is attainable. A set of experiments involving various sources of X ligands supported the theoretical conclusions. [ABSTRACT FROM AUTHOR]

Despite the advances in the field of carbon‐halogen bond formation, the straightforward catalytic access to selectively functionalized iodoaryls remains a challenge. Here, we report a one‐pot synthesis of ortho‐iodobiaryls from aryl iodides and bromides by palladium/norbornene catalysis. This new example of Catellani reaction features the initial cleavage of a C(sp2)−I bond, followed by the key formation of a palladacycle through ortho C−H activation, the oxidative addition of an aryl bromide and the ultimate restoration of the C(sp2)−I bond. A large variety of valuable o‐iodobiaryls has been synthesized in satisfactory to good yields and their derivatization have been described too. Beyond the synthetic utility of this transformation, a DFT study provides insights on the mechanism of the key reductive elimination step, which is driven by an original transmetallation between palladium(II)‐halides complexes. [ABSTRACT FROM AUTHOR]

The origins of ligand effects on PhCF3 reductive elimination from PdII complexes were computationally investigated by using energy decomposition analysis. The results indicate weak electrostatic interactions between ligands and Ph−Pd−CF3 lead to small barriers of PhCF3 reductive elimination. Two major factors affecting the electrostatic interactions are identified. [ABSTRACT FROM AUTHOR]

The reactivity of pnictinidenes [2‐(DippN=CH)‐6‐(DippNHCH2)C6H3]E (where E=As (1) or Sb (2)) toward substituted ortho‐ and para‐quinones is reported. The central pnictogen atom is easily oxidized by ortho‐quinones closing five‐membered EO2C2 ring. The oxidized antimony derivatives are stable species, while in the case of arsenic compounds the hydrogen of the pendant amino NHCH2 group cleaves one newly formed As−O bonds leading to the closure of a new azaarsole ring. Furthermore, a heating of these arsenic heterocycles resulted in a C−H bond activation at the NCH2 group involved in this heterocycle followed by a reductive elimination of corresponding catechols and arsinidene [2,6‐(DippN=CH)C6H3]As. Using of para‐quinones, resulted in the oxidation of the central atom with a concomitant hydrogen migration from NHCH2 group even in the case of the antimony derivatives. The reductive elimination of hydroquinones is in this case feasible for all compounds. Studied compounds were characterized by multi‐nuclear NMR, IR and Raman spectroscopy and single‐crystal X‐ray diffraction analysis. The theoretical study focusing the key compounds and reactions is also included. [ABSTRACT FROM AUTHOR]

Reductive elimination of alkyl−PdII−O is a synthetically useful yet underdeveloped elementary reaction. Here we report that the combination of an H‐bonding donor [PyH][BF4] and AgNO3 additive under toluene/H2O biphasic system can enable such elementary step to form alkyl nitrate. This results in the Pd0‐catalyzed asymmetric carbonitratations of (Z)‐1‐iodo‐1,6‐dienes with (R)‐BINAP as the chiral ligand, affording alkyl nitrates up to 96 % ee. Mechanistic studies disclose that the reaction consists of oxidative addition of Pd0 catalyst to vinyl iodide, anion ligand exchange between I− and NO3−, alkene insertion and SN2‐type alkyl−PdII−ONO2 reductive elimination. Evidences suggest that H‐bonding interaction of PyH⋅⋅⋅ONO2 can facilitate dissociation of O2NO− ligand from the alkyl−PdII−ONO2 species, thus enabling the challenging alkyl−PdII−ONO2 reductive elimination to be feasible. [ABSTRACT FROM AUTHOR]

The development of Pd‐ and Ni‐catalyzed reactions for C−C bond formation is one of the primary driving forces in modern organic synthesis and the fine chemical industry. However, understanding the role of conformational mobility in reaction mechanisms is a long‐standing challenge. We highlight the effect of a multirotamer (multiconformer) system on the effective Gibbs free energy of activation in the key C−C coupling process and promote the use of a simplified version of multiconformer transition state theory that is straightforward to apply. Multivariate regression helped to quantitatively map the effect of coupled organic substituents (their structural and electronic parameters), as well as to determine the relative activity of metals. We provide computational evidence for solvent control of the equilibrium in RE/C−C‐bond activation for some model complexes. We also demonstrate that Ni complexes, being unique in the catalysis of sp3‐sp3 couplings, can be more challenging for machine learning and computational chemistry. The modeling was performed at an exceptionally high level, DLPNO‐CCSD(T)/CBS//RIJCOSX‐PBE0‐D4/def2‐TZVP. The Conclusions section contains an infographic summarizing the key findings related to the fields of cross‐coupling catalysis, machine learning in catalysis, and computational chemistry. [ABSTRACT FROM AUTHOR]

Herein, we report visible light‐promoted single nickel catalysis for diverse carbon–heteroatom couplings under mild conditions. This mild, general, and robust method to couple diverse nitrogen, oxygen, and sulfur nucleophiles with aryl(heteroaryl)/alkenyl iodides/bromides exhibits a wide functional group tolerance and is applicable to late‐stage modification of pharmaceuticals and natural products. On the base of preliminary mechanistic studies, a NiI/NiIII cycle via the generation of active NiI complexes that appear from homolysis of NiII−I rather than NiII−aryl bond was tentatively proposed. [ABSTRACT FROM AUTHOR]

This chapter is dedicated to heterobimetallic complexes in which the two metal centers are not directly bound. Complexes are described in which the second metal resides in the second coordination sphere of the first metal and enables bond activation processes via synergistic activity with the first metal that are not available to the corresponding monometallic complexes. Both stoichiometric and catalytic bond activations are analyzed in the light of the type of reactions (e.g., H2 activation, polymerization, etc.). Both steric and electronic effects appear to play significant roles in many cases, and as such, they are examined when applicable. Indeed, spatial proximity between the two metal centers as well as electronic environment can allow for modification and tuning of reactivity. This realization has led to the development of switchable catalytic systems which are highlighted and discussed in terms of how they are manipulated (e.g., redox-switchable systems and cation-responsive systems). While significant progress has been made toward furthering our collective understanding of the behavior of these types of heterobimetallic complexes, this area is still ripe for future development. Additional systematic work is necessary to continue to push this area of chemistry forward. [ABSTRACT FROM AUTHOR]

Halogen bonds (XBs) between metal anions and halides have seldom been reported because metal anions are reactive for XB donors. The pyramidal-shaped Mn(CO)5− anion is a candidate metallic XB acceptor with a ligand-protected metal core that maintains the negative charge and an open site to accept XB donors. Herein, Mn(CO)5− is prepared by electrospray ionization, and its reaction with CH3I in gas phase is studied using mass spectrometry and density functional theory (DFT) calculation. The product observed experimentally at m/z = 337 is assigned as [IMn(CO)4(OCCH3)]−, which is formed by successive nucleophilic substitution and reductive elimination, instead of the halogen-bonded complex (XC) CH3−I···Mn(CO)5−, because the I···Mn interaction is weak within XC and it could be a transient species. Inspiringly, DFT calculations predict that replacing CH3I with CF3I can strengthen the halogen bonding within the XC due to the electro-withdrawing ability of F. More importantly, in so doing, the nucleophilic substitution barrier can be raised significantly, ~30 kcal/mol, thus leaving the system trapping within the XC region. In brief, the combination of a passivating metal core and the introduction of an electro-withdrawing group to the halide can enable strong halogen bonding between metallic anion and iodide. [ABSTRACT FROM AUTHOR]

The fundamental challenge of C−F bond formation by reductive elimination has been met by compounds of select transition metals and fewer main group elements. The work detailed herein expands the list of main group elements known to be capable of reductively eliminating a C−F bond to include tellurium. Surprising and novel modes of both sp2 and sp3 C−F bond formation were observed alongside formation of TeIV cations during two separate attempts to synthesize/characterize fluorinated organotellurium(VI) cations in superacidic media (SbF5/SO2ClF). Following detailed low‐temperature NMR experiments, the mechanisms of the two unique reductive elimination reactions were probed and investigated using density functional theory (DFT) calculations. Ultimately, we found that an "indirect" reductive elimination pathway is likely operative whereby Sb plays a key role in fluoride abstraction and C−F bond formation, as opposed to unimolecular reductive elimination from a discrete TeVI cation. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Five‐coordinate neutral Cu(III) complexes have long been considered as the key intermediates in copper‐mediated/catalyzed arene trifluoromethylative reactions, but the identity of these complexes remains elusive. Herein, we reported, for the first time, the preparation and characterization of these putative complexes [(bpy)Cu(CF3)2(C6F4R)] and investigation of their C(sp2)‐CF3 bond‐forming reductive elimination. Our mechanistic studies including kinetic studies, the effect of temperature and solvents, the effect of the para‐substitution of the ligand as well as DFT calculations suggest that C(sp2)‐CF3 reductive elimination process proceeds via synchronous bond‐breaking/bond‐forming process. [ABSTRACT FROM AUTHOR]

Density functional theory calculations were performed to investigate the reactions between an alkyl (or aryl) substrate and a pincer ligand at the κ3‐PPC Ni center, where reductive elimination or H elimination reactions occur. Ni complexes with PPC‐type pincer ligand showed different reactivity toward substrate, unlike conventional PCP‐type ligands. For substrates lacking β‐hydrogen, reductive elimination is preferred over completing α‐hydrogen elimination. For ethyl substrate, an intermediate and a TS for β‐H transfer with Gibbs free energy comparable to the reductive elimination were located. [ABSTRACT FROM AUTHOR]

An exclusively stereoselective reaction of AcOH elimination in the title acetate of cloprostenol was described, which led with high yield under Pd(PPh 3) 4 -NaH-THF catalysis to the corresponding 13E,15Z-derivative. In contrast, under the same conditions, the use of methyl ester of 15-acetate 11-deoxyprostaglandin E1 results in regioisomeric reductive elimination products. [Display omitted] • The reaction of prostaglandin with NaH in the presence of a Pd catalyst was target. • Relationships between configuration and energy of unsaturated alcohols were shown. • The structures were optimized by quantum chemical modeling methods. • Elimination products and reductive elimination products were obtained. • The structure of the obtained compounds was thoroughly determined by NMR. [ABSTRACT FROM AUTHOR]

We report on the synthesis of a distannyne supported by a pincer ligand bearing pendant amine donors that is capable of reversibly activating E‐H bonds at one or both of the tin centres through dissociation of the hemi‐labile N‐Sn donor/acceptor interactions. This chemistry can be exploited to sequentially (and reversibly) assemble mixed‐valence chains of tin atoms of the type ArSn{Sn(Ar)H}nSnAr (n=1, 2). The experimentally observed (decreasing) propensity towards chain growth with increasing chain length can be rationalized both thermodynamically and kinetically by the electron‐ withdrawing properties of the ‐Sn(Ar)H‐ backbone units generated via oxidative addition. [ABSTRACT FROM AUTHOR]

The reductive elimination on [(Me3P)2Pt(MeOH)(CH3)3]+, 2P, complex performed in MeOH solution and inside a [Ga4L6]12− metallocage are computationally analysed by mean of QM and MD simulations and compared with the mechanism of gold parent systems previously reported [Et3PAu(MeOH)(CH3)2]+, 2Au. The comparative analysis between the encapsulated Au(III) and Pt(IV)‐counterparts shows that there are no additional solvent MeOH molecules inside the cavity of the metallocage for both systems. The Gibbs energy barriers for the 2P reductive elimination calculated at DFT level are in good agreement with the experimental values for both environments. The effect of microsolvation and encapsulation on the rate acceleration are evaluated and shows that the latter is far more relevant, conversely to 2Au. Energy decomposition analysis indicates that the encapsulation is the main responsible for most of the energy barrier reduction. Microsolvation and encapsulation effects are not equally contributing for both metal systems and consequently, the reasons of the rate acceleration are not the same for both metallic systems despite the similarity between them. [ABSTRACT FROM AUTHOR]

Density functional theory computation indicates that bridge splitting of [PtIIR2(μ‐SEt2)]2 proceeds by partial dissociation to form R2Pta(μ‐SEt2)PtbR2(SEt2), followed by coordination of N‐donor bromoarenes (L‐Br) at Pta leading to release of PtbR2(SEt2), which reacts with a second molecule of L‐Br, providing two molecules of PtR2(SEt2)(L‐Br‐N). For R=4‐tolyl (Tol), L‐Br=2,6‐(pzCH2)2C6H3Br (pz=pyrazol‐1‐yl) and 2,6‐(Me2NCH2)2C6H3Br, subsequent oxidative addition assisted by intramolecular N‐donor coordination via PtIITol2(L‐N,Br) and reductive elimination from PtIV intermediates gives mer‐PtII(L‐N,C,N)Br and Tol2. The strong σ‐donor influence of Tol groups results in subtle differences in oxidative addition mechanisms when compared with related aryl halide oxidative addition to palladium(II) centres. For R=Me and L‐Br=2,6‐(pzCH2)2C6H3Br, a stable PtIV product, fac‐PtIVMe2{2,6‐(pzCH2)2C6H3‐N,C,N)Br is predicted, as reported experimentally, acting as a model for undetected and unstable PtIVTol2{L‐N,C,N}Br undergoing facile Tol2 reductive elimination. The mechanisms reported herein enable the synthesis of PtII pincer reagents with applications in materials and bio‐organometallic chemistry. [ABSTRACT FROM AUTHOR]

In recent years, the reactivity of gold complexes was shown to extend well beyond π‐activation and to hold promises to achieve selective cross‐couplings in several C−C and C−E (E=heteroatom) bond forming reactions. Here, with the aim of exploiting new organometallic species for cross‐coupling reactions, we report on the Au(III)‐mediated C(sp2)−C(sp) occurring upon reaction of the cyclometalated complex [Au(CCH2N)Cl2] (1, CCH2N=2‐benzylpyridine) with AgPhCC. The reaction progress has been monitored by NMR spectroscopy, demonstrating the involvement of a number of key intermediates, whose structures have been unambiguously ascertained through 1D and 2D NMR analyses (1H, 13C, 1H‐1H COSY, 1H‐13C HSQC and 1H‐13C HMBC) as well as by HR‐ESI‐MS and X‐ray diffraction studies. Furthermore, crystallographic studies have serendipitously resulted in the authentication of zwitterionic Au(I) complexes as side‐products arising from cyclization of the coupling product in the coordination sphere of gold. The experimental work has been paralleled and complemented by DFT calculations of the reaction profiles, providing valuable insight into the structure and energetics of the key intermediates and transition states, as well as on the coordination sphere of gold along the whole process. Of note, the broader scope of the cross‐coupling at the Au(III) CCH2N centre has also been demonstrated studying the reaction of 1 with C(sp2)‐based nucleophiles, namely vinyl and heteroaryl tin and zinc reagents. These reactions stand as rare examples of C(sp2)−C(sp2) cross‐couplings at Au(III). [ABSTRACT FROM AUTHOR]

Halogen bonds (XBs) between metal anions and halides have seldom been reported because metal anions are reactive for XB donors. The pyramidal-shaped Mn(CO)5− anion is a candidate metallic XB acceptor with a ligand-protected metal core that maintains the negative charge and an open site to accept XB donors. Herein, Mn(CO)5− is prepared by electrospray ionization, and its reaction with CH3I in gas phase is studied using mass spectrometry and density functional theory (DFT) calculation. The product observed experimentally at m/z = 337 is assigned as [IMn(CO)4(OCCH3)]−, which is formed by successive nucleophilic substitution and reductive elimination, instead of the halogen-bonded complex (XC) CH3−I···Mn(CO)5−, because the I···Mn interaction is weak within XC and it could be a transient species. Inspiringly, DFT calculations predict that replacing CH3I with CF3I can strengthen the halogen bonding within the XC due to the electro-withdrawing ability of F. More importantly, in so doing, the nucleophilic substitution barrier can be raised significantly, ~30 kcal/mol, thus leaving the system trapping within the XC region. In brief, the combination of a passivating metal core and the introduction of an electro-withdrawing group to the halide can enable strong halogen bonding between metallic anion and iodide.

Germylenes, organic compounds of divalent germanium, are often considered as promising catalytic systems efficient in reactions of oxidative addition and reductive elimination, including SET reactions. However, the systematic studies of their redox properties, allowing for the quantitative evaluation of the levels of frontier molecular orbitals and the stability of single electron transfer products, are extremely limited in number. In this work, a series of germylenes with various types of stabilization: N-Ge-N, (N→)C-Ge-C(←N), N-Ge-N(←N), O-Ge-O(←N) и (N→)O-Ge-O(←N) ("-" -a covalent bond, stabilization is achieved by p-donation of a lone pair of electrons of N or O, "→" -donor-acceptor bond) were characterized by cyclic voltammetry. The results were compared with UV/Vis spectroscopy data and DFT calculations. All germylenes studied in MeCN and THF with Bu4NPF6 as a supporting electrolyte are chemically irreversibly oxidized in the potential range of 0.5-1.4 V vs. Ag/AgCl. In all cases, as estimated by the quantum chemical calculations, the HOMO remains at the covalently unsaturated germanium center although being significantly redistributed over the molecular system. In turn, electroreduction of germylenes is possible only in the presence of a strong electron-withdrawing substituent or a pyridine ring depleted in electron density donated to germanium. In both cases, the LUMO is localized exactly on these moieties and is absent on the germanium. Thus, the use of stabilizing groups makes it possible both to improve germylene stability and to fine-tune their HOMO level that determines their ability to participate in oxidative addition reactions. [ABSTRACT FROM AUTHOR]

Distannylated Tröger's base Me3Sn−C6H3−C3N2H6−C6H3−SnMe3 (TB‐(SnMe3)2) reacted with PtCl2(cod) (cod=1,5‐cyclooctadiene) to yield a mixture of macrocyclic diplatinum complex composed of two Tröger's base ligands and two Pt(cod) units (1) and oligomers of the −C6H3−C3N2H6−C6H3−Pt(cod)‐ units (2). Heating a toluene solution of isolated complex 1 and excess PPh3 caused reductive elimination of a cyclic dimer of Tröger's base. The product is obtained in a diastereoselective manner. 1H NMR and DFT studies suggested the molecular structure having the Tröger's base units with smaller arylene rings (ϕ=65–66°) than that reported for dimethyl Tröger's base (ϕ=103°). [ABSTRACT FROM AUTHOR]

The potential access to CoIV species for promoting transformations that are particularly challenging at CoIII still remains underexploited in the context of Cp*Co‐catalyzed C−H functionalization reactions. Herein, we disclose a combined experimental and computational strategy for uncovering the participation of Cp*CoIV species in a Cp*Co‐mediated C−S bond‐reductive elimination. These studies support the intermediacy of high‐valent Cp*Co species in C−H functionalization reactions, under oxidative conditions, when involving nucleophilic coupling partners. [ABSTRACT FROM AUTHOR]

The structure of [Ir{(4-Cl-C6H4N3)C(dppm)-κ3P,C,N}(dppm-κ2P,P′)]Cl·1.5CH2Cl2·0.5C7H8 (C57H48Cl2IrN3P4·1.5CH2Cl2·0.5C7H8) (2), dppm = bis(diphenylphosphino)methane {systematic name: [7-(4-chlorophenyl)-1,1,3,3-tetraphenyl-5,6,7-triaza-κN7-1,3λ4-diphospha-κP1-hepta-4,6-dien-4-yl][methylenebis(diphenylphosphine)-κ2P,P′]iridium(I) chloride–dichloromethane–toluene (2/3/1)}, resulting from the reaction of [IrClH{C(dppm)2-κ3P,C,P)(MeCN)]Cl (1a) with 1-azido-4-chlorobenzene, shows a monocationic five-coordinate IrI complex with a distorted trigonal–bipyramidal geometry. In 2, the iridium centre is coordinated by the neutral triazeneylidenephosphorane (4-Cl-C6H4N3)C(dppm) acting as a PCN pincer ligand, and a chelating dppm unit. The structure of the coordination compound [IrCl(CN)H(C(dppm)2-κ3P,C,P)]·CH3CN, (C52H45ClIrNP4·CH3CN) (1b) [systematic name: chloridocyanidohydrido(1,1,3,3,5,5,7,7-octaphenyl-1,3λ5,5λ4,7-tetraphospha-κ2P1,P7-hept-3-en-4-yl)iridium(III) acetonitrile monosolvate], prepared from 1a and KCN, reveals an octahedral IrIII central atom with a meridional PCP pincer carbodiphosphorane (CDP) ligand; the chloride ligand is located trans to the central carbon of the CDP functionality while the hydrido and cyanido ligands are situated trans to each other. The chiral coordination compound [Ir(CN)((4-Cl-C6H4N3)CH(CH(P(Ph)2)2)-κ3P,C,N)(dppm-κ2P,P′)]·2CH3OH, (C58H48ClIrN4P4·2CH3OH) (3) (systematic name: {4-[3-(4-chlorophenyl)triazenido-κN3]-1,1,3,3-tetraphenyl-1,3λ5-diphospha-κP1-but-2-en-4-yl}cyanido[methylenebis(diphenylphosphine)-κ2P,P′]iridium(III) methanol disolvate), formed via prolonged reaction of 1-azido-4-chlorobenzene with 1b, features a six-coordinate IrIII central atom. The iridium centre is coordinated by the dianionic facial PCN pincer ligand [(4-Cl-C6H4N3)CH(CH(P(Ph2)2)2)], a cyanido ligand trans to the central carbon of the PCN pincer ligand and a chelating dppm unit. Complex 2 exhibits a 2:1 positional disorder of the Cl− anion. The CH2Cl2 and C7H8 solvent molecules show occupational disorder, with the toluene molecule exhibiting additional 1:1 positional disorder with some nearly overlying carbon atoms.

Herein, we describe the mechanistic details on the oxidatively induced reductive elimination of isolated methyl iridium and ruthenium metallacycle complexes. It was demonstrated that the otherwise challenging C─C bond formation is indeed facilitated by external oxidation, being enabled under mild conditions. Computational analyses supported the proposed high‐valent pathway, where the energy barrier for reductive elimination significantly decreases upon the metallic oxidation to facilitate the desired C─C bond formation. [ABSTRACT FROM AUTHOR]

A new family of cationic, bidentate (P^N)gold(III) fluoride complexes has been prepared and a detailed characterization of the gold‐fluoride bond has been carried out. Our results correlate with the observed reactivity of the fluoro ligand, which undergoes facile exchange with both cyano and acetylene nucleophiles. The resulting (P^N)arylgold(III)C(sp) complexes have enabled the first study of reductive elimination on (P^N)gold(III) systems, which demonstrated that C(sp2)−C(sp) bond formation occurs at higher rates than those reported for analogous phosphine‐based monodentate systems. [ABSTRACT FROM AUTHOR]

We performed density functional calculations to study conversion of carbon dioxide to formic acid through designed catalyst of Rh-decorated phosphorous-doped fullerenes. Two paths of reaction are considered for this conversion. In the first pathway, CO2 is transferred to formate intermediate using the catalyst, and then, through a sequence of oxidative addition and reductive elimination reactions, formic acid is released; density functional theory results showed that in this path the oxidative addition is an easy and quite exothermic process. It is also shown that the rate-determining step in the hydrogenation of CO2 catalyzed by Rh-decorated phosphorous-doped fullerene complexes is the release of formic acid from formate intermediate. In the other pathway after the formation of rhodium formate intermediate and then addition of H2, the formic acid complex is released directly through metathesis process; our results showed a moderate energy barrier for the metathesis process, in which the oxidation state of the Rh center does not change. This barrier is found to be much smaller than the barrier of the reductive process in the first pathway. [ABSTRACT FROM AUTHOR]

Oxidative addition and reductive elimination are defining reactions of transition‐metal organometallic chemistry. In main‐group chemistry, oxidative addition is now well‐established but reductive elimination reactions are not yet general in the same way. Herein, we report dihydrodialanes supported by amidophosphine ligands. The ligand serves as a stereochemical reporter for reversible reductive elimination/oxidative addition chemistry involving AlI and AlIII intermediates. [ABSTRACT FROM AUTHOR]

The digold(I) complex [Au2Cl2(Cy2PCH2PCy2)] reacts with 4,4′‐diphenylene diboronic acid to form a triangular macrocyclic complex with twisted Au‐P‐C‐P‐Au groups at the three corners. The synthesis of the complex and its chemical oxidation produced [6]cycloparaphenylene ([6]CPP) in 59 % overall yield. [ABSTRACT FROM AUTHOR]

The dative Pd→B interaction in a series of RDPBR' Pd0 and PdII complexes (RDPBR'=(o‐PR2C6H4)2BR', diphosphinoborane) was analyzed using XRD, 11B NMR spectroscopy and NBO/NLMO calculations. The borane acceptor discriminates between the oxidation state PdII and Pd0, stabilizing the latter. Reaction of lithium amides with [(RDPBR')PdII(4‐NO2C6H4)I] chemoselectively yields the C−N coupling product. DFT modelling indicates no significant impact of PdII→B coordination on the inner‐sphere reductive elimination rate. [ABSTRACT FROM AUTHOR]

A new family of phosphine‐ligated dicyanoarylgold(III) complexes has been prepared and their reactivity towards reductive elimination has been studied in detail. Both, a highly positive entropy of activation and a primary 12/13C KIE suggest a late concerted transition state while Hammett analysis and DFT calculations indicate that the process is asynchronous. As a result, a distinct mechanism involving an asynchronous concerted reductive elimination for the overall C(sp2)−C(sp)N bond forming reaction is characterized herein, for the first time, complementing previous studies reported for C(sp3)−C(sp3), C(sp2)−C(sp2), and C(sp3)−C(sp2) bond formation processes taking place on gold(III) species. [ABSTRACT FROM AUTHOR]

A small library of tetrasubstituted [10]cycloparaphenylene ([10]CPP) derivatives bearing alkyl, alkenyl, alkynyl and aryl substituents was constructed by a Pd‐catalyzed cross‐coupling reaction starting from tetratriflate [10]CPP 5 e, which was readily available in high yields on a >2 g scale. The CPP skeleton increases the reactivity of aryl triflate for oxidative addition to the Pd species, and 5 e is 10 times more reactive than its linear paraphenylene analogue, as determined by competition experiments. Theoretical calculations suggest that the accumulation of the small strain relief from each paraphenylene unit not involved in the reaction is responsible for the observed enhanced reactivity. [ABSTRACT FROM AUTHOR]

In the present study the dependence of the reaction rate of carbon‐carbon reductive elimination from R3PAu(MeOH)(CH3)2 (R=Me, Et) complexes inside [Ga4L6]12− metallocage on the nature of the phosphine ligand is investigated by computational means. The reductive elimination mechanism is analyzed in methanol solution and inside the metallocage. Classical molecular dynamics simulations reveal that the smaller the gold complex (which depends on the phosphine ligand size) the larger the number of solvent molecules encapsulated. The size of the phosphine ligands defines the space that is left available inside the cavity that can be occupied by solvent molecules. The Gibbs energy barriers calculated at DFT level, in excellent agreement with experiment both in solution and in the metallocage, show that the presence/absence of explicit solvent molecules inside the cavity significantly modifies the reaction rate. [ABSTRACT FROM AUTHOR]

With the aim of exploiting new organometallic species for cross‐coupling reactions, we report here on the AuIII‐mediated Caryl−P bond formation occurring upon reaction of C^N cyclometalated AuIII complexes with phosphines. The [Au(C^N)Cl2] complex 1 featuring the bidentate 2‐benzoylpyridine (CCON) scaffold was found to react with PTA (1,3,5‐triaza‐7‐phosphaadamantane) under mild conditions, including in water, to afford the corresponding phosphonium 5 through C−P reductive elimination. A mechanism is proposed for the title reaction based on in situ 31P{1H} NMR and HR‐ESI‐MS analyses combined with DFT calculations. The C−P coupling has been generalized to other C^N cyclometalated AuIII complexes and other tertiary phosphines. Overall, this work provides new insights into the reactivity of cyclometalated AuIII compounds and establishes initial structure–activity relationships to develop AuIII‐mediated C−P cross‐coupling reactions. [ABSTRACT FROM AUTHOR]

Transition‐metal‐catalyzed cross‐coupling reactions are central to many organic synthesis methodologies. Traditionally, Pd, Ni, Cu, and Fe catalysts are used to promote these reactions. Recently, many studies have showed that both homogeneous and heterogeneous Au catalysts can be used for activating selective cross‐coupling reactions. Here, an overview of the past studies, current trends, and future directions in the field of gold‐catalyzed coupling reactions is presented. Design strategies to accomplish selective homocoupling and cross‐coupling reactions under both homogeneous and heterogeneous conditions, computational and experimental mechanistic studies, and their applications in diverse fields are critically reviewed. Specific topics covered are: oxidant‐assisted and oxidant‐free reactions; strain‐assisted reactions; dual Au and photoredox catalysis; bimetallic synergistic reactions; mechanisms of reductive elimination processes; enzyme‐mimicking Au chemistry; cluster and surface reactions; and plasmonic catalysis. In the relevant sections, theoretical and computational studies of AuI/AuIII chemistry are discussed and the predictions from the calculations are compared with the experimental observations to derive useful design strategies. [ABSTRACT FROM AUTHOR]