Electron-withdrawing Ligands Research Articles

Low pKa Phosphido-Boranes Capture Carbon Dioxide with Exceptional Strength: DFT Predictions Followed by Experimental Validation.

We have developed a class of phosphido-boranes (BoPh's) with formula X+[R2PBH3-] that bind CO2 with exceptional strength (ΔG = -8.2 to -24.0 kcal/mol) at ambient conditions. We use quantum mechanics (QM) to determine how the choice of electron-donating versus electron-withdrawing ligand impacts the CO2 binding strength, in the presence of a donating borane moiety. We also examine the role of the cation in CO2 binding, finding that the ion position relative to the bound CO2 dramatically alters binding strength. We find that the BoPh with two ethyl ligands Li[Et2PBH3] leads to ΔG = -24.0 kcal/mol upon CO2 binding while Li[Ph2PBH3] leads to ΔG = -12.8 kcal/mol. We synthesized the BoPh with two phenyl ligands Li[Ph2PBH3] to validate the QM-predicted stability and predicted pKa.

Unactivated Pd-catalyzed oxidative cross-coupling reactions of arenes with benzene: a theoretical and experimental study

Oxidative C–H bond activated palladium-catalyzed aromatic cross-coupling reactions offer advantages of fewer required synthetic steps but disadvantages of loss of inherent regioselectivity and selectivity. In one proposed catalytic cycle, each arene adds to a palladium carboxylate catalyst according to a concerted metalation deprotonation mechanism, followed by reductive elimination to couple the arenes and the replenishment of the catalyst by an oxidant. Using this proposed mechanism, molecular structures and free energy profiles were calculated for coupling of benzene with a range of heteroarenes containing various substituents and with several Pd-carboxylate catalysts. Reaction kinetics were analysed using the energetic span model, predicting turnover frequencies (TOFs) of heterocoupling (HB and BH) and homocoupling (HH and BB) pathways and assessing degrees of turnover frequency control (XTOFs). More electron-withdrawing carboxylate ligands and more electron-donating heteroarene substituents decrease activation and reaction free energies of addition steps, with C-2 more favourable than C-3. When heteroarene and catalyst choice are particularly favourable, the first association can become exergonic, causing a significant change in catalytic kinetics. When not exergonic, free energy for addition of benzene is almost always higher, leading to large energetic spans and slower TOFs (BB < HB < BH < HH). Non-exergonic pathways are also faster with more electron-withdrawing ligands and more electron-donating heteroarene substituents because of lower energy addition steps and a smaller energetic span. For exergonic associations, the low-energy arene–catalyst intermediate creates a larger energetic span, slowing down the HH and HB pathways. More electron-withdrawing ligands and more electron-donating substituents increase the relative TOF for BH, and the reaction requires only small excesses of benzene to induce heterocoupling.

Silylation-Driven Volatility Enhancement in Mononuclear Calcium, Magnesium, and Barium Complexes with Monomethyl or Silyl Ether and Bis(diketonate).

Magnesium, calcium, and barium heteroleptic complexes were synthesized by the substitution reaction of the bis(trimethylsilyl)amide of Mg(btsa)2·DME, Ca(btsa)2·DME, and Ba(btsa)2·2DME with an ethereal group and hfac ligands (btsa = bis(trimethylsilyl)amide, DME = dimethoxyethane). The compounds Mg(dts)(hfac)2 (1), Ca(dts)(hfac)2 (2), Mg(dmts)(hfac)2 (3), Ca(dmts)(hfac)2 (4), and Ba(dmts)(hfac)2 (5) were fabricated and analyzed using various techniques, including Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, thermogravimetric analyses, and elemental analysis (dts = 2,2-dimethyl-3,6,9-trioxa-2-siladecane, dmts = 2,2-dimethyl-3,6,9,12-tetraoxa-2-silatridecane, hfac = hexafluoroacetylacetonate). The structures of complexes 2, 4, and 5 were confirmed using single-crystal X-ray crystallography; all complexes display monomeric structures. All compounds underwent trimethylsilylation of the coordinating ethereal alcohols (meeH and tmgeH) in the presence of HMDS as byproducts because of their increasing acidity originating from the electron-withdrawing hfac ligands. (meeH = 2-(2-methoxyethoxy)ethan-1-ol, tmgeH = tri(ethylene glycol) monoethyl ether, HMDS = hexamethyldisilazane).

Dual External Field Strategy in Regulating the Superhalogen Characteristics of the Non-Noble Metal Constituted Tantalum Oxide Clusters.

The identification of the non-noble metal constituted TaO cluster as a potential analogue to the noble metal Au is significant for the development of tailored materials. It leverages the superatom concept to engineer properties with precision. However, the impact of incrementally integrating TaO units on the electronic configurations and properties within larger TaO-based clusters remains to be elucidated. By employing the density functional theory calculations, the global minima and low-lying isomers of the TanOn (n = 2-5) clusters were determined, and their structural evolution was disclosed. In the cluster series, Ta5O5 was found to possess the highest electron affinity (EA) with a value of 2.14 eV, based on which a dual external field (DEF) strategy was applied to regulate the electronic property of the cluster. Initially, the electron-withdrawing CO ligand was affixed to Ta5O5, followed by the application of an oriented external electric field (OEEF). The CO ligation was found to be able to enhance the Ta5O5 cluster's electron capture capability by adjusting its electron energy levels, with the EA of Ta5O5(CO)4 peaking at 2.58 eV. Subsequently, the introduction of OEEF further elevated the EA of the CO-ligated cluster. Notably, OEEF, when applied along the +x axis, was observed to sharply increase the EA to 3.26 eV, meeting the criteria for superhalogens. The enhancement of EA in response to OEEF intensity can be quantified as a functional relationship. This finding highlights the advantage of OEEF over conventional methods, demonstrating its capacity for precise and continuous modulation of cluster EAs. Consequently, this research has adeptly transformed tantalum oxide clusters into superhalogen structures, underscoring the effectiveness of the DEF strategy in augmenting cluster EAs and its promise as a viable tool for the creation of superhalogens.

Electron-withdrawing organic ligand for high-efficiency all-perovskite tandem solar cells

Electron-withdrawing organic ligand for high-efficiency all-perovskite tandem solar cells

Sulfonium Cation in the Service of π-Acid Catalysis.

While still rare, cationic ligands offer much promise as tunable electron-withdrawing ligands for π-acid catalysis. Recently, we introduced pincer-type sulfonium cations into the list of available strongly π-acidic ancillary ligands. However, the M-S bond in sulfonium complexes of these ligands was found highly labile, precluding their catalytic applications. Herein we demonstrate that this obstacle can be overcome by increasing the rigidity of the sulfonium pincer scaffold. X-ray analyses confirm that despite bearing a formal positive charge, the sulfur atom of this newly designed sulfonium ligand maintains its coordination to the Pt(II)-center, while DFT calculations indicate that by doing so it strongly enhances the electrophilic character of the metal. Kinetic studies carried out on three model cycloisomerization reactions prove that such a tris-cationic sulfonium-Pt(II) complex is highly reactive, compared to its thioether-based analogue. This proof-of-concept study presents the first example of employing sulfonium-based ligands in homogeneous catalysis.

Tuning the surface electronic structure of noble metal aerogels to promote the electrocatalytic oxygen reduction

The sluggish kinetics of the oxygen reduction reaction (ORR) is the bottleneck for various electrochemical energy conversion devices. Regulating the electronic structure of electrocatalysts by ligands has received particular attention in deriving valid ORR electrocatalysts. Here, the surface electronic structure of Pt-based noble metal aerogels (NMAs) was modulated by various organic ligands, among which the electron-withdrawing ligand of 4-methylphenylene effectively boosted the ORR electrocatalysis. Theoretical calculations suggested the smaller energy barrier for the transformation of O* to OH* and downshift the d-band center of Pt due to the interaction between 4-methylphenylene and the surface metals, thus enhancing the ORR intrinsic activity. Both Pt3Ni and PtPd aerogels with 4-methylphenylene decoration performed significant enhancement in ORR activity and durability in different media. Remarkably, the 4-methylphenylene modified PtPd aerogel exhibited the higher half-wave potential of 0.952 V and the mass activity of 10.2 times of commercial Pt/C. This work explained the effect of electronic structure on ORR electrocatalytic properties and would promote functionalized NMAs as efficient ORR electrocatalysts.

Investigation of the Relationship between Electronic Structures and Bioactivities of Polypyridyl Ru(II) Complexes.

Ruthenium (Ru)-based organometallic drugs have gained attention as chemotherapeutic and bioimaging agents due to their fewer side effects and excellent physical optical properties. Tuning the electronic structures of Ru complexes has been proven to increase the cytotoxicity of cancer cells and the luminescent efficiency of the analytical probes. However, the relationship between electronic structures and bioactivities is still unclear due to the potential enhancement of both electron donor and acceptor properties. Thus, we investigated the relationship between the electronic structures of Ru(II) complexes and cytotoxicity by optimizing the electron-withdrawing (complex 1), electron-neutral (complex 2), and electron-donating (complex 3) ligands through DFT calculations, bioactivities tests, and docking studies. Our results indicated that it was not sufficient to consider only either the effect of electron-withdrawing or electron-donating effects on biological activities instead of the total electronic effects. Furthermore, these complexes with electron-donating substituents (complex 3) featured unique "off-on" luminescent emission phenomena caused by the various "HOMO-LUMO" distributions when they interacted with DNA, while complex with electron-withdrawing substituent showed an "always-on" signature. These findings offer valuable insight into the development of bifunctional chemotherapeutic agents along with bioimaging ability.

The effect of replacing linker with carboxylic acid ligands on the oxygen evolution performance of metal-organic frameworks

Metal-organic frameworks (MOFs) are versatile platforms for developing various applications, owing to their structural diversity and functional tunability. The catalytic performance of metal-organic frameworks (MOFs) can be improved by introducing defects using monocarboxylate ligands, but the role of these ligands remains unclear. Herein, we show how doping MOFs with electron-withdrawing or electron-donating monocarboxylate ligands affects their oxygen evolution reaction (OER) performance. We further demonstrate that ferrocene derivatives as doped ligands can significantly enhance the OER performance of MOFs, owing to the strong synergistic effects between ferrocene derivatives and MOFs. Different from other doping MOF, ferrocene derivatives doped MOFs (1,1'-Fc-Ni-BDC) exhibit remarkable electrocatalytic activity with a low overpotential of 387 mV at 10 mA cm−2, and possess good electrochemical stability. Density functional theory (DFT) calculations reveal that the active sites are not on ferrocene derivatives, but rather on MOFs, and that ferrocene derivatives facilitate the formation of OER intermediates. Our findings provide new insights into the role of ligands in modulating the OER performance of MOFs. This work offers a new perspective to develop efficient MOF-based electrocatalysts by introducing electronegative metallocene ligands.

Lewis Acids and Electron-Withdrawing Ligands Accelerate CO Coordination to Dinuclear CuI Compounds.

A series of dinuclear molecular copper complexes were prepared and used to model the binding and Lewis acid stabilization of CO in heterogeneous copper CO2 reduction electrocatalysts. Experimental studies (including measurement of rate and equilibrium constants) and electronic structure calculations suggest that the key kinetic barrier for CO binding may be a σ-interaction between CuI and the incoming CO ligand. The rate of CO coordination can be increased upon the addition of Lewis acids or electron-withdrawing substituents on the ligand backbone. Conversely, Keq for CO coordination can be increased by adding electron density to the metal centers of the compound, consistent with stronger π-backbonding. Finally, the electrochemically measured kinetic results were mapped onto an electrochemical zone diagram to illustrate how these system changes enabled access to each zone.

Back to the future: asymmetrical DπA 2,2'-bipyridine ligands for homoleptic copper(i)-based dyes in dye-sensitised solar cells.

Metal complexes used as sensitisers in dye-sensitised solar cells (DSCs) are conventionally constructed using a push-pull strategy with electron-releasing and electron-withdrawing (anchoring) ligands. In a new paradigm we have designed new DπA ligands incorporating diarylaminophenyl donor substituents and phosphonic acid anchoring groups. These new ligands function as organic dyes. For two separate classes of DπA ligands with 2,2'-bipyridine metal-binding domains, the DSCs containing the copper(i) complexes [Cu(DπA)2]+ perform better than the push-pull analogues [Cu(DD)(AA)]+. Furthermore, we have shown for the first time that the complexes [Cu(DπA)2]+ perform better than the organic DπA dye in DSCs. The synthetic studies and the device performances are rationalised with the aid of density functional theory (DFT) and time-dependent DFT (TD-DFT) studies.

Theoretical Investigations on MIL-100(M) (M=Cr, Sc, Fe) with High Adsorption Selectivity for Nitrogen and Carbon Dioxide over Methane.

The removal of impurity gases (N2 , CO2 ) in natural gas is critical to the efficient use of natural gas. In this work, the selective adsorption for N2 and CO2 over CH4 on MIL-100 (M) (M=4 Cr, 10 Cr, 6 Fe, 1 In, 1 Sc, 3 V) is studied by density functional theory (DFT) calculations. The calculated adsorption energy of the large-size cluster model (LC) of MIL-100 (M) shows that the 4 MIL-100 (4 Cr) is the best at the refinement of natural gas due to the lower adsorption energy of CH4 (-2.58 kJ/mol) in comparison with that of N2 (-21.49 kJ/mol) and CO2 (-23.82 kJ/mol). 1 MIL-100 (1 Sc) and 1 MIL-100 (6 Fe) can also achieve selective adsorption and follows the order 4 MIL-100 (4 Cr)>1 MIL-100 (1 Sc)>1 MIL-100 (6 Fe). In the research of the selective adsorption mechanism of MIL-100 (M) (M=4 Cr, 1 Sc, 6 Fe), the independent gradient model (IGM) indicates that these outstanding adsorbents interact with CO2 and N2 mainly through the electrostatic attractive interaction, while the van der Walls interaction dominates in the interaction with CH4. The atomic Projected Density of State (PDOS) further confirms that CH4 contributes least to the intermolecular interaction than that of CO2 and N2 . Through the scrutiny of molecular orbitals, it is found that electrons transfer from the gas molecule to the metal site in the adsorption of CO2 and N2 . Not only does the type of the metallic orbitals, but also the delocalization of the involved orbitals determines the selective adsorption performance of MIL-100. Both Cr and Sc share their orbitals with the gases, making 1 MIL-100 (1 Sc) another potential effective separator for CH4 . Additionally, the comparison of adsorption energy and PDOS shows that the introduction of ligands such as benzene impedes the electron donation from gas molecules (CO2 , N2 ) to the metal site, indicating electron-withdrawing ligands will further favor the adsorption.

Enhancing the Air Stability of Dimolybdenum Paddlewheel Complexes: Redox Tuning through Fluorine Substituents.

The optical and electrochemical properties of quadruply bonded dimolybdenum paddlewheel complexes (Mo2PWCs) make them ideal candidates for incorporation into functional materials or devices, but one of the greatest bottlenecks for this is their poor stability toward atmospheric oxygen. By tuning the potential at which the Mo2 core is oxidized, it was possible to increase the tolerance of Mo2PWCs to air. A series of homoleptic Mo2PWCs bearing fluorinated formamidinate ligands have been synthesized and their electrochemical properties studied. The oxidation potential of the complexes was tuned in a predictable fashion by controlling the positions of the fluorine substituents on the ligands, as guided by a Hammett relationship. Studies into the air stability of the resulting complexes by multinuclear NMR spectroscopy show an increased tolerance to atmospheric oxygen with increasingly electron-withdrawing ligands. The heteroleptic complex Mo2(DFArF)3(OAc) [where DFArF = 3,5-(difluorophenyl)formamidinate] shows remarkable tolerance to oxygen in the solid state and in chloroform solutions. Through the employment of easily accessible ligands, the stability of the Mo2 core toward oxygen has been enhanced, thereby making Mo2PWCs with electron-withdrawing ligands more attractive candidates for the development of functional materials.

The Conversion of Superoxide to Hydroperoxide on Cobalt(III) Depends on the Structural and Electronic Properties of Azole-Based Chelating Ligands.

Conversion from superoxide (O2−) to hydroperoxide (OOH−) on the metal center of oxygenases and oxidases is recognized to be a key step to generating an active species for substrate oxidation. In this study, reactivity of cobalt(III)-superoxido complexes supported by facially-capping tridentate tris(3,5-dimethyl-4-X-pyrazolyl)hydroborate ([HB(pzMe2,X)3]−; TpMe2,X) and bidentate bis(1-methyl-imidazolyl)methylborate ([B(ImN-Me)2Me(Y)]−; LY) ligands toward H-atom donating reagent (2-hydroxy-2-azaadamantane; AZADOL) has been explored. The oxygenation of the cobalt(II) precursors give the corresponding cobalt(III)-superoxido complexes, and the following reaction with AZADOL yield the hydroperoxido species as has been characterized by spectroscopy (UV-vis, resonance Raman, EPR). The reaction of the cobalt(III)-superoxido species and a reducing reagent ([CoII(C5H5)2]; cobaltocene) with proton (trifluoroacetic acid; TFA) also yields the corresponding cobalt(III)-hydroperoxido species. Kinetic analyses of the formation rates of the cobalt(III)-hydroperoxido complexes reveal that second-order rate constants depend on the structural and electronic properties of the cobalt-supporting chelating ligands. An electron-withdrawing ligand opposite to the superoxide accelerates the hydrogen atom transfer (HAT) reaction from AZADOL due to an increase in the electrophilicity of the superoxide ligand. Shielding the cobalt center by the alkyl group on the boron center of bis(imidazolyl)borate ligands hinders the approaching of AZADOL to the superoxide, although the steric effect is insignificant.

Role of the Trifluoropropynyl Ligand in Blue-Shifting Charge-Transfer States in Emissive Pt Diimine Complexes and an Investigation into the PMMA-Imposed Rigidoluminescence and Rigidochromism.

Square-planar PtII complexes are of interest as dopants for the emissive layer of organic light-emitting diodes. Herein, the photophysics of three Pt bipyridyl complexes with the strongly e- withdrawing, high-field, 3,3,3-trifluoropropynyl ligand has been investigated. One complex, (phbpy)PtC2CF3 (phbpy = 6-phenyl-2,2'-dipyridyl), has also been characterized by single-crystal X-ray diffraction. All complexes reported are emissive in both RT CH2Cl2 solution (ΦPL = 0.007 to 0.027) and PMMA film (ΦPL = 0.25 to 0.42). The trifluoropropynyl ligand elevates the energy of the MLCT and LL'CT states above that of the IL π-π* state, resulting in IL emission in all cases. The emission energies of the trifluoropropynyl compounds are also blue-shifted relative to the analogous pentafluorophenylethynyl compounds, suggesting that the trifluoropropynyl ligand is one of the most electron-withdrawing alkynyl ligands. Rate constants for radiative and nonradiative deactivation were determined from experimentally determined values of ΦPL and excited-state lifetimes in both solution and PMMA films. The increase in ΦPL upon incorporation into PMMA film (rigidoluminescence) results from a decrease in the rate constant for non-radiative relaxation. Experimental activation energies for excited-state decay in combination with TDDFT are consistent with the rigidoluminescence resulting from an increase in the energy of the non-emissive triplet metal-centered state. Two of the complexes investigated, (Ph2bpy)Pt(C2CF3)2 and (t-Bu2bpy)Pt(C2CF3)2, where t-Bu2bpy = 4,4'-di-tert-butyl-2,2'-dipyridyl and Ph2bpy = 4,4'-diphenyl-2,2'-dipyridyl, exhibit concentration-dependent excimer emission (orange) along with monomer emission (blue), enabling fine-tuning of the emission color. However, excimer emission was absent in cured PMMA films up to the solubility limit for solution processing of (Ph2bpy)Pt(C2CF3)2 in CH2Cl2, demonstrating the diffusional nature of excimer formation.

Alkyne Metathesis with d2 Re(V) Alkylidyne Complexes Supported by Phosphino-Phenolates: Ligand Effect on Catalytic Activity and Applications in Ring-Closing Alkyne Metathesis.

A family of d2 Re(V) alkylidyne complexes bearing two decorated phosphino-phenolates (POs) and a labile pyridine ligand were prepared that can efficiently promote alkyne metathesis reactions in toluene. The relative activity of these complexes varies with the PO ligands. Complexes with an electron-rich metal center have a higher activity. Ligand exchange experiments suggest that the pyridine ligands of the Re(V) alkylidynes with more electron-donating PO ligands are more labile and are more easily released to generate catalytically active species. However, complexes with electron-withdrawing PO ligands are more air-stable than those with electron-donating PO ligands. These Re(V) alkylidyne catalysts can promote the homometathesis of functionalized internal alkyl- and aryl-alkynes, as well as ring-closing alkyne metathesis (RCAM) of methyl-capped diynes, forming macrocycles with a ring size ≥12 efficiently for concentrations ≤5 mM. These reactions represent the first examples of RCAM mediated by non-d0 alkylidyne complexes. The Re(V) alkylidyne catalysts tolerate a wide range of functional groups including ethers, esters, ketones, aldehydes, alcohols, phenols, amines, amides, and heterocycles. Moreover, the catalytic RCAM reactions promoted by robust Re(V) alkylidyne catalysts could also proceed normally in wet toluene.

Enhancing catalytic activity of copper(II) complexes by curcuminoid as electron-withdrawing ligand for silane water-crosslinking reaction: a joint experimental and theoretical study

Enhancing catalytic activity of copper(II) complexes by curcuminoid as electron-withdrawing ligand for silane water-crosslinking reaction: a joint experimental and theoretical study

Oxidative Addition of a Hypervalent Iodine Compound to Cycloplatinated(II) Complexes for the C-O Bond Construction: Effect of Cyclometalated Ligands.

The complex [PtMe(Obpy)(OAc)2(H2O)], 2a, Obpy = 2,2'-bipyridine N-oxide, is prepared through the reaction of [PtMe(Obpy)(SMe2)], 1a, by 1 equiv of PhI(OAc)2 via an oxidative addition (OA) reaction. Pt(IV) complex 2a attends the process of C-O bond reductive elimination (RE) reaction to form methyl acetate and corresponding Pt(II) complex [Pt(Obpy)(OAc)(H2O)], 3a. The kinetic of OA and RE reactions are investigated by means of different spectroscopies. The obtained results show that the reaction rates of OA step of 1a are faster than its analogous complex [PtMe(ppy)(SMe2)], 1b, ppy = 2-phenylpyridine. The density functional theory (DFT) calculations signify that the OA reaction initiated by a nucleophilic attack of the platinum(II) central atom of 1b on the iodine(III) atom while it had commenced by a nucleophilic substitution reaction of coordinated SMe2 in 1a with a carbonyl oxygen atom of PhI(OAc)2. Our calculation revealed that the key step for 1a is an acetate transfer from the I(III) to Pt(II) through a formation of square pyramidal iodonium complex. This can be attributed to the more electron-withdrawing character of Obpy ligand than to ppy which reduces the nucleophilicity of Pt atom in 1a. Furthermore, 2a with electron-withdrawing Obpy ligand prone to C-O bond formation faster than complex [PtMe(ppy)(OAc)2(H2O)], 2b, with an electron-rich ppy ligand which conforms to the anticipation that REs occur faster on electron-poor metal centers.

Development of Magnesium Borate Electrolytes: Explaining the Success of Mg[B(hfip)4]2 Salt

Magnesium batteries are one of the most promising post-lithium technologies. One of the main challenges preventing its commercialization is to find an efficient and safe electrolyte. The electrolyte, playing the role of the blood in a battery, interacts with all battery components and must be highly compatible with all of them. The development of Cl-free electrolyte systems is desired to avoid corrosion issues, and many studies suggest magnesium tetrakis(hexafluoroisopropyloxy)borate (Mg[B(hfip)4]2) as one of the best candidates in terms of electrochemical properties and chemical stability. Here we present an in-depth analysis of the unique structure of this salt and the interactions generated in the electrolyte among the dissociated ions. The results show a delicate balance between electron-withdrawing effects and ligand stabilization in B(hfip)4−, crucial from the point of view of magnesium electrolytes. Moreover, the bulk nature of B(hfip)4− limits the anion-cation contacts to infrequent interactions through fluorine atoms. This has consequences not only for ion transport but also for hindering the anion decomposition towards the formation of MgF2. Taken together, we managed to demystify the exclusive nature of B(hfip)4− anion, thereby allowing for further rational development of new anion structures.

Design of an Electron-Withdrawing Benzonitrile Ligand for Ni-Catalyzed Cross-Coupling Involving Tertiary Nucleophiles.

The design of new ligands for cross-coupling is essential for developing new catalytic reactions that access valuable products such as pharmaceuticals. In this report, we exploit the reactivity of nitrile-containing additives in Ni catalysis to design a benzonitrile-containing ligand for cross-coupling involving tertiary nucleophiles. Kinetic and Hammett studies are used to elucidate the role of the optimized ligand, which demonstrate that the benzonitrile moiety acts as an electron-acceptor to promote reductive elimination over β-hydride elimination and stabilize low-valent Ni. With these conditions, a protocol for decyanation-metalation and Ni-catalyzed arylation is conducted, enabling access to quaternary α-arylnitriles from disubstituted malononitriles.