Coordination Mode Research Articles

AgMAsS3 (M = Cd, Hg): Double d10 Cation-Containing Thioarsenites(III) Exhibiting High Photocurrent Response and Moderate Second Harmonic Generation.

Thioarsenites(III) are an advanced functional material platform owing to the stereochemically active lone pair cations. In this paper, two novel quaternary thioarsenites(III), AgMAsS3 (M = Cd, Hg), are successfully obtained by introducing double d10 cations. In the compounds, d10 cations show a variety of different coordination modes ([AgS4] and [HgS4] in AgHgAsS3 vs [AgS5] and [CdS6] in AgCdAsS3). As a result, AgHgAsS3 and AgCdAsS3 crystallize in the noncentrosymmetric Cc space group and centrosymmetric C2/c space group, respectively. The band gaps of AgHgAsS3 and AgCdAsS3 are determined experimentally as 1.90 and 2.20 eV, respectively. Meanwhile, title compounds exhibit strong photocurrent responses. Specifically, AgHgAsS3 has a large birefringence of 0.18 at 2100 nm and a moderate second harmonic generation of (0.5 × AgGaS2). Moreover, the origin of linear and nonlinear optical responses is investigated based on first-principles calculations. This study enriches the family of MI-MII-As-Q (M = Ag, Cu; MII = Zn, Cd, Hg; Q = chalcogen) chalcogenides and helps to understand and design other multifunctional optical materials.

A Series of Novel 3D Coordination Polymers Based on the Quinoline-2,4-dicarboxylate Building Block and Lanthanide(III) Ions-Temperature Dependence Investigations.

A series of novel 3D coordination polymers [Ln2(Qdca)3(H2O)x]·yH2O (x = 3 or 4, y = 0-4) assembled from selected lanthanide ions (Ln(III) = Nd, Eu, Tb, and Er) and a non-explored quinoline-2,4-dicarboxylate building block (Qdca2- = C11H5NO42-) were prepared under hydrothermal conditions at temperatures of 100, 120, and 150 °C. Generally, an increase in synthesis temperature resulted in structural transformations and the formation of more hydrated compounds. The metal complexes were characterized by elemental analysis, single-crystal and powder X-ray diffraction methods, thermal analysis (TG-DSC), ATR/FTIR, UV/Vis, and luminescence spectroscopy. The structural variety of three-dimensional coordination polymers can be ascribed to the temperature effect, which enforces the diversity of quinoline-2,4-dicarboxylate ligand denticity and conformation. The Qdca2- ligand only behaves as a bridging or bridging-chelating building block binding two to five metal centers with seven different coordination modes arising mainly from different carboxylate group coordination types. The presence of water molecules in the structures of complexes is crucial for their stability. The removal of both coordinated and non-coordinated water molecules leads to the disintegration and combustion of metal-organic frameworks to the appropriate lanthanide oxides. The luminescence features of complexes, quantum yield, and luminescent lifetimes were measured and analyzed. Only the Eu complexes show emission in the VIS region, whereas Nd and Er complexes emit in the NIR range. The luminescence properties of complexes were correlated with the crystal structures of the investigated complexes.

Mono and Dinuclear Palladium Pincer Complexes of NNSe Ligand as a Catalyst for Decarboxylative Direct C-H Heteroarylation of (Hetero)arenes.

This report describes the synthesis of a new NNSe pincer ligand and its mono and dinuclear palladium(II) pincer complexes. In the absence of a base, a dinuclear pincer palladium complex (C1) was isolated, while in the presence of an Et3N base a mononuclear palladium pincer complex (C2) was obtained. The new ligand and complexes were characterized using techniques like 1H, 13C{1H} Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared (FTIR), High-Resolution Mass Spectrometry (HRMS), Ultraviolet-visible (UV-Visible), and cyclic voltammetry. Both complexes showed pincer coordination mode with a distorted square planar geometry. The complex C1 has two pincer ligands attached through a Pd-Pd bond in a dinuclear pincer fashion. The air and moisture-insensitive, thermally robust palladium pincer complexes were used as the catalyst for decarboxylative direct C-H heteroarylation of (hetero)arenes. Among the complexes, dinuclear pincer complex C1 showed better catalytic activity. A variety of (hetero)arenes were successfully activated (48-87% yield) using only 2.5 mol% of catalyst loading under mild reaction conditions. The PPh3 and Hg poisoning experiments suggested a homogeneous nature of catalysis. A plausible reaction pathway was proposed for the dinuclear palladium pincer complex catalyzed decarboxylative C-H bond activation reaction of heteroarenes.

The “Periodic Table” of 1-methylbenzotriazole: Zinc(II) Complexes

In an attempt to fill in the empty Zn position in the “Periodic Table” of 1-methylbenzotriazole (Mebta), reactions between Zn(II) sources and this ligand were carried out. The detailed synthetic studies provided access to complexes [ZnX2(Mebta)2] (X = Cl, 1; X = Br, 3; X = I, 4), (MebtaH)2[ZnCl4] (2), tet-[Zn(NO3)2(Mebta)2] (5), oct-[Zn(NO3)2(Mebta)2] (6), and [Zn(Mebta)4](Y)2 [Y = ClO4, 7; Y = PF6, 8]. Solid-state thermal decomposition of 2 leads to 1 in quantitative yield. The structures of 3, 4, 5, 6, and 7 were determined by single-crystal crystallography. The structures of the remaining complexes were proposed based on spectroscopic evidence. In all compounds, Mebta behaves as monodentate ligand using the nitrogen of the position 3 as donor. Complexes 1–4, 7, and 8 are tetrahedral. Complexes 5 and 6 are isostoichiometric and their preparation in pure forms depends on the reaction conditions; in the former the ZnII atom has a tetrahedral geometry, whereas in the latter the metal ion is octahedral. This case of rare isomerism arises from the monodentate (in 5) vs. bidentate (in 6) coordination of the nitrato groups. Extensive π–π stacking interactions and non-classical H bonds build interesting 3D architectures in the structurally characterized complexes. The compounds were characterized by IR, far-IR, and Raman spectroscopies in the solid state, and the data were interpreted in terms of the structures (known or proposed) of the complexes and the coordination modes of the organic and inorganic ligands involved. The solid-state structures of the complexes are not retained in solution, as proven by NMR (1H, 13C[1H]) spectroscopy and molar conductivity data. The thermal decomposition study of 1 and 3 leads to stable intermediates with 1:1 stoichiometry, i.e., ZnX2(Mebta). Based on far-IR spectra, polymeric tetrahedral structures are possible with simultaneous presence of terminal and bridging X− groups. Liquid-phase ab initio (MP2) and gas-phase DFT calculations, performed on Mebta and the nitrato complexes, respectively, shed light on the tendency of Mebta for N3-coordination, and the existence and relative stabilities of 5 and 6.

Pyrrolyl-Bridged Metallocene Complexes: From Synthesis, Electronic Structure, to Single-Molecule Magnetism.

The π- and σ-basicity of the pyrrolyl ligand affords several coordination modes. A sterically encumbering coordination sphere around metal centers may foster new coordination modes for the pyrrolyl ligand. Here, we present three dinuclear rare earth complexes [Cp*2RE(μ-pyr)]2, [RE = Y (1), La (2), Dy (3); Cp* = pentamethylcyclopentadienyl, pyr = pyrrolyl], which were synthesized through a protonolysis reaction between allyl complexes and H-pyrrole. Each metal is ligated by two Cp* ligands and the N atom of the pyrrolyl ring while interacting with the π-system of the other pyrrolyl ligand, yielding an unprecedented coordination mode for pyrrolyl best described as [((η5-Cp*)2RE)2(μ-1η2-pyr-2κN)(μ-2η2-pyr-1κN)]. The steric congestion implemented by the Cp* ligands forces this asymmetric coordination of the pyrrolyl ligand. 1-3 were characterized by crystallography, electrochemistry, and spectroscopy. Density functional theory calculations on 1 uncovered the bonding situation between the pyrrolyl ligand and the yttrium(III) ion. Excitingly, 3 displays slow magnetic relaxation under zero dc field with Ueff = 98.9(7) cm-1 and τo = 6.7(1) × 10-8 s, placing it among coveted dinuclear metallocene single-molecule magnets. CASSCF calculations provided the energy of the crystal field states of DyIII and confirmed the barrier height.

Diboriranid σ‐Komplexe von d‐ und p‐Blockmetallen

AbstractDiboriranide sind die kleinstmöglichen monoanionischen Aromaten; dennoch sind bisher nur wenige Beispiele bekannt und ihre Reaktivität sowie Koordinationschemie noch völlig unerforscht. Wir berichten über einen einfachen Syntheseweg in drei Stufen zum ersten Peraryldiboriranid c‐(DurB)2CPh− in Form seines Lithiumsalzes über das entsprechende nicht‐klassische Diboriran, das seinerseits aus dem leicht zugänglichen 1,2‐Dichlordiboran(4) (Dur=2,3,5,6‐Tetramethylphenyl) erhalten wird. Mit der Herstellung und vollständigen Charakterisierung repräsentativer Komplexe mit Zinn, Kupfer, Gold und Zink demonstrieren wir die starke Präferenz des Diboriranids für σ‐Koordination gegenüber Hauptgruppen‐ und Übergangsmetallzentren unter Erhalt des 2e− π‐Systems des B2C‐Rings.

Diboriranide σ-Complexes of d- and p-Block Metals.

Diboriranides are the smallest conceivable monoanionic aromatic cycles, yet only limited examples have been reported and their reactivity and complexation behavior remain completely unexplored. We report a straightforward synthesis of the first peraryl diboriranide c-(DurB)2 CPh- as its lithium salt in three steps via the corresponding non-classical diborirane from a readily available 1,2-dichlorodiborane(4) (Dur=2,3,5,6-tetramethylphenyl). With the preparation and complete characterization of representative complexes with tin, copper, gold and zinc, we demonstrate the strong preference of the diboriranide for σ-type coordination modes towards main group and transition metal centers under unperturbed retention of the three-membered B2 C-ring's 2e- π-system.

Imidazol(in)ium-2-Thiocarboxylate Zwitterion Ligands: Structural Aspects in Coordination Complexes

Azolium-2-thiocarboxylate zwitterion ligands have emerged as a promising class of compounds in the field of coordination chemistry due to their unique structural features and versatile applications. These ligands are characterized by a positively charged azolium ring and a negatively charged thiocarboxylate moiety, making them capable of forming stable coordination complexes with various metal ions. One of the key structural aspects that make these ligands attractive for coordination chemistry is their ability to adopt diverse coordination modes with metal centers. The nature of these ligands enables them to engage in both monodentate and bidentate coordination, resulting in the formation of chelated complexes with enhanced stability and controlled geometry or the formation of polynuclear structures. This versatility in coordination behavior allows for the design of tailored ligands with specific metal-binding preferences, enabling the creation of unique and finely tuned coordination architectures. The azolium-2-thiocarboxylate zwitterionic ligands offer a promising platform for the design of coordination complexes with diverse structural architectures.

Synthesis, structure, theoretical studies, and properties of dinuclear Cu(II) and novel trinuclear Co(II) complexes with a more flexible 3-MeOsalamo-like ligand

A more flexible 3-methoxysalamo-like ligand H2L and its dinuclear Cu(II) complex [Cu2(L)(NO3)2] (1) and novel trinuclear Co(II) complex [{Co3(L)2(µ3OAc)2}2]⋅9CH2Cl2 (2) were synthesized. The self-assembly reaction was driven by the unique N,O-donor coordination environments. Single crystal X-ray diffraction analysis showed that two Cu(II) atoms occupy the N2O2 and O4 cavities of the ligand (L)2− unit in complex 1, respectively, and two oxygen atoms on the two mono-dentate nitrate groups have also participated in the coordination for the charge balance of complex 1. The stretching of chemical bonds of complex 1 can be perfectly explained by the Jahn-Teller effect. The novel salamo-based Co(II) complex 2 containing µ3OAc− coordination mode was discovered for the first time. The trinuclear Co(II) complex embodies the advantage of the salamo-based ligand, which has a good flexible form. The binding ratio of the ligand to the Co(II) center was verified by a UV–Vis titration experiment, which is consistent with the single crystal X-ray diffraction result. The energy gaps between the ligand and complexes 1 and 2 were obtained by DFT calculations, and a new theory-softness was proposed. The degree of softness affected the shapes of the complexes. Hirshfeld analysis, IRI, and electrostatic potential proved the existence of hydrogen bond, π···π, CH···π interactions, and van der Waals force. These weak interaction forces affected the structures of the complexes. Finally, the fluorescence properties of the ligand and its complexes were studied.

Toughening self-healing elastomer crosslinked by metal–ligand coordination through mixed counter anion dynamics

Mechanically tough and self-healable polymeric materials have found widespread applications in a sustainable future. However, coherent strategies for mechanically tough self-healing polymers are still lacking due to a trade-off relationship between mechanical robustness and viscoelasticity. Here, we disclose a toughening strategy for self-healing elastomers crosslinked by metal–ligand coordination. Emphasis was placed on the effects of counter anions on the dynamic mechanical behaviors of polymer networks. As the coordinating ability of the counter anion increases, the binding of the anion leads to slower dynamics, thus limiting the stretchability and increasing the stiffness. Additionally, multimodal anions that can have diverse coordination modes provide unexpected dynamicity. By simply mixing multimodal and non-coordinating anions, we found a significant synergistic effect on mechanical toughness ( > 3 fold) and self-healing efficiency, which provides new insights into the design of coordination-based tough self-healing polymers.

Mechanistic Study of Reduction of Nitrite to NO by the Copper(II) Complex: Different Concerted Proton-Electron Transfer Reactivity between Nitrite and Nitro Complexes.

The literature contains numerous reports of copper complexes for nitrite (NO2-) reduction. However, details of how protons and electrons arrive and how nitric oxide (NO) is released remain unknown. The influence of the coordination mode of nitrite on reactivity is also under debate. Kundu and co-workers have reported nitrite reduction by a copper(II) complex [J. Am. Chem. Soc. 2020, 142, 1726-1730]. In their report, the copper(II) complex reduced nitrite using a phenol derivative as a reductant, resulting in NO, a hydroxyl copper(II) complex, and the corresponding biphenol. Also, the involvement of proton-coupled electron transfer was proposed by mechanistic studies. Herein, density functional theory calculations were performed to determine a mechanism for reduction of nitrite by a copper(II) complex. As a result of geometry optimization of an initial complex, two possible structures were obtained: Cu-ONO and Cu-NO2. Two possible reaction pathways initiated from Cu-ONO or Cu-NO2 were then considered. The calculation results indicated that the Cu-ONO pathway is energetically favorable. When changes in the electronic structure were considered, both pathways were found to involve concerted proton-electron transfer (CPET). In addition, an intrinsic reaction coordinate analysis revealed that the two pathways were achieved by different types of CPET. Furthermore, an intrinsic bond orbital analysis clearly indicated that, in the Cu-ONO pathway, the chemical events involved proceeded concertedly yet asynchronously.

QM/MM and MM MD Simulations on Enzymatic Degradation of the Nerve Agent VR by Phosphotriesterase.

V-type nerve agents are hardly degraded by phosphotriesterase (PTE). Interestingly, the PTE variant of BHR-73MNW can effectively improve the hydrolytic efficiency of VR, especially for its Sp-enantiomer. Here, the whole enzymatic degradation of both Sp and Rp enantiomers of VR by the wild-type PTE and its variant BHR-73MNW was investigated by quantum mechanics/molecular mechanics (QM/MM) calculations and MM molecular dynamics simulations. Present results indicate that the degradation of VR can be initiated by the nucleophilic attack of the bridging OH- and the zinc-bound water molecule. The QM/MM-predicted energy barriers for the hydrolytic process of Sp-VR are 19.8 kcal mol-1 by the variant with water as a nucleophile and 22.0 kcal mol-1 by the wild-type PTE with OH- as a nucleophile, and corresponding degraded products are bound to the dinuclear metal site in monodentate and bidentate coordination modes, respectively. The variant effectively increases the volume of the large pocket, allowing more water molecules to enter the active pocket and resulting in the improvement of the degradation efficiency of Sp-VR. The hydrolysis of Rp-VR is triggered only by the hydroxide with an energy span of 20.6 kcal mol-1 for the wild-type PTE and 20.7 kcal mol-1 for the variant BHR-73-MNW PTE. Such mechanistic insights into the stereoselective degradation of VR by PTE and the role of water may inspire further studies to improve the catalytic efficiency of PTE toward the detoxification of nerve agents.

2D and 3D Ag(I) coordination polymers with a 2-methylimidazole substituted cyclotriphosphazene ligand: Structures and dye adsorption properties

Coordination polymers are a promising crystalline framework for dye capture and separation in recent years. We are reporting herein the two new, Ag(I) coordination polymers, namely {[Ag3(MeIm-Cp)2](NO3)3}n (1) and {[Ag(MeIm-Cp)](CH3PhSO3)} (2), were synthesized from hexapodal-shaped 2-methylimidazole substituted cyclotriphosphazene, (MeIm-Cp). MeIm-Cp was characterised by 1H NMR, 31P NMR and mass analysis. Structure of each isolated compounds were assigned by single crystal X-ray crystallography. In complex 1, MeIm-Cp has a κ6N coordination mode by connecting six Ag(I) ions to constitute a 3D coordination framework whereas the ligand in complex 2 displays κ4N coordination mode via linking four Ag(I) ions together to create a 2D coordination polymer. Topologically, coordination polymer 1 exhibits a 4,4,6-connected three nodal net with point symbol {44.62}3{46.68.8}2, while coordination polymer 2 displays a four-connected network having the point symbol {43.63}. According to thermogravimetric analysis, the thermal stability of MeIm-Cp is higher than complexes. The synthesized coordination polymers were used for the adsorption of some cationic and anionic organic dyes in aqueous media, Dye adsorption studies were performed out using UV–Vis. absorption spectroscopy. Adsorption experiments show that complex 1 removes the anionic methyl orange (MO) and tartrazine (E102) from water but shows no adsorption behaviour toward the cationic methylene blue (MB).

In-situ investigation on tensile deformation and fracture behaviors of inhomogeneous microstructure during laser repair of Ti-6Al-4 V titanium alloy

Laser additive manufacturing, with its small heat-affected zone, high forming accuracy, and adjustable filler material, has great potential for use in the repair of aircraft engine blades. Nevertheless, it is inevitable to introduce a non-uniform microstructure during laser processing, which will cause a decrease in the components’ mechanical properties. To gain further insight into the mechanics of inhomogeneous structures under tensile load, digital image correlation (DIC) technology and in-situ tensile test are applied to study the mechanical response and fracture mechanism of inhomogeneous structures. It is indicated that the position of stress concentration changes in the β columnar during the tensile process, whereas the same remains constant in equiaxed crystals. The coordination deformation ability and mode of the RZ exhibit notable differences compared to that of the HAZ. The slips between the α phases in the β columnar lead to micro-cracks at the phase boundary and the propagation of Z-shaped cracks, while crack propagation along the grain boundary in the equiaxed crystal due to coordinated deformation by the different grains.

Triboranate derivatives of calcium and strontium

This contribution reports the alkaline earth-mediated formation of homonuclear sigma bonding between the metalloid element, boron. The resultant triborane anions result from the formal dismutation of bis(pinacolato)diboron (B2pin2) and the generation of putative heavier group 2 boryl intermediates. Initial reactions of the heavier alkaline earth bis-(trimethylsilyl)amides, [Ae{N(SiMe3)2}2] (Ae = Ca or Sr), with an equimolar quantity of bis(pinacolato)diboron (B2pin2) provided the 4-coordinate group 2 silazide diborane adducts [Ae(B2pin2){N(SiMe3)2}2] in which the diborane acts as a bidentate ligand via κ2-O,O' coordination. Reaction of the calcium species at 60 °C with a further three molar equivalents of B2pin2 induced the elimination of pinBN(SiMe3)2 and the formation of the bis-triboranate derivative, [Ca(B3pin3)2], in which the 6-coordinate calcium centre is bound in a κ3-O,O',O''-coordination mode by the three contiguous pinacolate oxygen atoms of both catena-B(sp2)-B(sp3)-B(sp2) bonded anions. Although analogous treatment of [Ae(B2pin2){N(SiMe3)2}2] provided similar triboranate anion formation, in this case two equivalents of the strontium silazide were retained within the structure of the trimetallic species, [Sr(B3pin3)2(Sr{N(SiMe3)2}2)2]. Despite these contrasting outcomes both triboranate complexes provide rare examples of catena-boron species beyond the common diboranes, (R2B-BR2), in which the homologated unit is propagated by electron precise and otherwise unsupported B-B bonds.

Template-OrientedPolyaniline-Supported Palladium Nanoclusters for Reductive Homocoupling of Furfural Derivatives.

Developing well-defined structures and desired properties for porous organic polymer (POP) supported catalysts by controlling their composition, size, and morphology is of great significance. Herein, we report a preparation of polyaniline (PANI) supported Pd nanoparticles (NPs) with controllable of the structure and morphology. The protocol involves the introduction of MnO2 with different crystal structures (α, β, γ, δ, ε) serving as both reaction templates and oxidants. MnO2 selectively oxidizes the aniline to polyaniline with diverse regular distribution of benzene and quinone, thus leading to the Pd/PANI catalyst growth mode which prominently impacts the charge transfer between Pd and PANI, as well as the dispersion of metal NPs. In particular, Pd/ε-PANI greatly improves the turnover frequency (TOF), up to 88.3 h-1,in the reductive coupling of the furfural derivatives to potential bio-based plasticizers. Systematic characterizations reveal the unique oxidation state of the support in the Pd/ε-PANI catalyst and coordination mode of Pd that drives the formation of highly dispersed Pd nanoclusters. Density functional theory (DFT) calculations show the more electron rich Pd/PANI catalyst has the lower energy barrier in the oxidative addition step, which favors the C-C coupling reaction.

Potassium and Cesium Fluorinated β-Diketonates: Effect of a Cation and Terminal Substituent on Structural and Thermal Properties.

As potential precursors for the synthesis of fluoroperovskites, a family of heavy alkali metal (MI = K, Cs) fluorinated β-diketonates were prepared and characterized by elemental analysis, IR, and powder-XRD. The crystal structures of the new six complexes, MI(β-dikF)(H2O)X, X = 0 or 1, were also determined. The structural diversity of this poorly explored class of complexes was discussed, including the preferred types of cation polyhedra and the ligand coordination modes, and the thermal properties of the metal β-diketonates were studied by TG-DTA in an inert (He) atmosphere. The data obtained allowed us to reveal the effect of the metal cation and the terminal substituent on the structural and thermal features of this family of complexes.

5-Fluoro-3-(1H-indol-3-ylmeth-yl)-1H-indole.

The title compound, C17H13FN2, was synthesized as a potential ligand for the construction of metal-organic frameworks. The two indole motifs present two potential coordination modes. It crystallizes in the ortho-rhom-bic system with space group P212121. The dihedral angle between the fused ring systems is 68.77 (10)°. Weak F⋯H inter-actions are observed in the crystal.

Synergistic Palladium/Lewis acid-Catalyzed Regio- and Stereo-divergent Bissilylation of Alkynoates: Scope, Mechanism, and Origin of Selectivity.

Transition metal-catalyzed bissilylation reactions of alkynes with disilane reagents have become one of the most straightforward and efficient protocols to rapidly produce structurally diverse alkenyl silicon derivatives. In these reactions, the utilization of unsymmetrical disilane reagents provided the possibilities for reactivity enhancement as well as the synthetic merits in contrast to symmetrical disilane reagents. However, a major yet challenging objective is achieving precise control over the selectivity including the regioselectivity and thecis/trans-selectivity. Herein we realized the first divergent bissilylation of alkynoates with our developed air-stable disilane reagent TMDQ by means of synergistic Pd/Lewis acid catalytic system. The catalytic system precisely dictates the selectivity, resulting in the divergent synthesis of 1,2-bissilyl alkenes. The power of these 1,2-bissilyl alkenes serving as the key synthetic intermediates has been clearly demonstrated by rapid construction of diverse motifs and densely functionalized biologically active compounds. In addition, the origins of the switchable selectivities were well elucidated by experimental and computational studies on the reaction mechanism and were mainly attributed to different ligand steric effects, the use of the specific disilane reagent TMDQ and the different coordination modes of different Lewis acid with alkynoates.

Template‐Oriented Polyaniline‐Supported Palladium Nanoclusters for Reductive Homocoupling of Furfural Derivatives

AbstractDeveloping well‐defined structures and desired properties for porous organic polymer (POP) supported catalysts by controlling their composition, size, and morphology is of great significance. Herein, we report a preparation of polyaniline (PANI) supported Pd nanoparticles (NPs) with controllable structure and morphology. The protocol involves the introduction of MnO2 with different crystal structures (α, β, γ, δ, ϵ) serving as both the reaction template and the oxidant. The different forms of MnO2 each convert aniline to a PANI that contains a unique regular distribution of benzene and quinone. This leads to the Pd/PANI catalysts with different charge transfer properties between Pd and PANI, as well as different dispersions of the metal NPs. In this case, the Pd/ϵ‐PANI catalyst greatly improves the turnover frequency (TOF; to 88.3 h−1), in the reductive coupling of furfural derivatives to potential bio‐based plasticizers. Systematic characterizations reveal the unique oxidation state of the support in the Pd/ϵ‐PANI catalyst and coordination mode of Pd that drives the formation of highly dispersed Pd nanoclusters. Density functional theory (DFT) calculations show the more electron rich Pd/PANI catalyst has the lower energy barrier in the oxidative addition step, which favors the C−C coupling reaction.