High Bond Dissociation Energy Research Articles

Enantioconvergent Palladium‐Catalyzed Alkylation of Tertiary Allylic C−H Bonds

AbstractEnantioconvergent catalysis enables the conversion of racemic molecules into a single enantiomer in perfect yield and is considered an ideal approach for asymmetric synthesis. Despite remarkable advances in this field, enantioconvergent transformations of inert tertiary C−H bonds remain largely unexplored due to the high bond dissociation energy and the surrounding steric repulsion that pose unparalleled constraints on bond cleavage and formation. Here, we report an enantioconvergent Pd‐catalyzed alkylation of racemic tertiary allylic C−H bonds of α‐alkenes, providing a unique approach to access a broad range of enantioenriched γ,δ‐unsaturated carbonyl compounds featuring quaternary carbon stereocenters. Mechanistic studies reveal that a stereoablative event occurs through the rate‐limiting cleavage of tertiary allylic C−H bonds to generate σ‐allyl‐Pd species, and the achieved E/Z‐selectivity of σ‐allyl‐Pd species effectively regulates the diastereoselectivity via a nucleophile coordination‐enabled SN2′‐allylation pathway.

Pd-Catalyzed Activation of Carbon-Carbon Bonds in Hydroxymethylfurfural Derivatives.

Palladium-catalyzed activation of C-C bonds in organic molecules is a powerful tool for the synthesis of value-added compounds. 5-Hydroxymethylfurfural (HMF) derivatives are a promising class of biomass-derived chemicals that have received considerable attention due to their potential applications in the synthesis of biologically active molecules and materials. However, the selective activation of unstrained C-C bonds is a challenging task, mainly due to their relatively high bond dissociation energies. Herein, we report a palladium-catalyzed method for the efficient C-C bond activation of HMF derivatives, enabling their arylation with iodobenzenes. Mechanistic studies, including reaction-profile analysis, competition experiments and head-space IR spectroscopy suggest a decarboxylative mechanism.

Unraveling the Impact of Acetylation Patterns in Chitosan Oligomers on Cu2+ Ion Binding: Insights from DFT Calculations.

Chitosans are partially acetylated polymers of glucosamine, structurally characterized by their degree of polymerization as well as their fraction and pattern of acetylation. These parameters strongly influence the physico-chemical properties and biological activities of chitosans, but structure-function relationships are only poorly understood. As an example, we here investigated the influence of acetylation on chitosan-copper complexation using density functional theory. We investigated the electronic structures of completely deacetylated and partially acetylated chitosan oligomers and their copper-bound complexes. Frontier molecular orbital theory revealed bonding orbitals for electrophiles and antibonding orbitals for nucleophiles in fully deacetylated glucosamine oligomers, while partially acetylated oligomers displayed bonding orbitals for both electrophiles and nucleophiles. Our calculations showed that the presence of an acetylated subunit in a chitosan oligomer affects the structural and the electronic properties of the oligomer by generating new intramolecular interactions with the free amino group of neighboring deacetylated subunits, thereby influencing its polarity. Furthermore, the band gap energy calculated from the fully and partially deacetylated oligomers indicates that the mobility of electrons in partially acetylated chitosan oligomers is higher than in fully deacetylated oligomers. In addition, fully deacetylated oligomers form more stable complexes with higher bond dissociation energies with copper than partially acetylated ones. Interestingly, in partially acetylated oligomers, the strength of copper binding was found to be dependent on the pattern of acetylation. Our study provides first insight into the influence of patterns of acetylation on the electronic and ion binding properties of chitosans. Depending on the intended application, the obtained results can serve as a guide for the selection of the optimal chitosan for a specific purpose.

Exceeding 10 000 h of Lifetime in Blue Fluorescent Organic Light‐Emitting Diodes by Introducing an Electron Leakage Pathway

Electron leakage is one of the most critical factors for the degradation of blue fluorescent organic light‐emitting diodes (FOLEDs), as it occurs when electrons injected from the cathode flow to an electron‐blocking layer (EBL) without being entirely consumed within an emissive layer (EML). To address this issue, this study introduces the concept of an electron leakage‐pathway (ELP). Anthracene core materials, used as hosts for blue FOLEDs were doped in the EBL to prevent its direct damage to the EBL molecules by constructing the ELP. This study shows that using an anthracene core with high bond dissociation energy (BDE) in the anionic state as the ELP is the most effective way to increase the lifetime of the FOLED, demonstrating over 400 h. of LT90 (the time taken for the luminance to decrease to 90% of its initial value), which corresponds to an increase of 33% compared to the lifetime without the ELP. Remarkably, under a commonly used brightness level of 500 cd m−2 in smartphones, an LT50 of over 10 000 h was obtained. Ultimately, this study outlines a strategy for increasing the lifetime of blue FOLEDs through simple modifications to the device structure, without requiring the development of EBL materials or complex device engineering.

Structural insights into hydrolytic defluorination of difluoroacetate by microbial fluoroacetate dehalogenases.

Fluorine forms the strongest single bond to carbon with the highest bond dissociation energy among natural products. However, fluoroacetate dehalogenases (FADs) have been shown to hydrolyze this bond in fluoroacetate under mild reaction conditions. Furthermore, two recent studies demonstrated that the FAD RPA1163 from Rhodopseudomonas palustris can also accept bulkier substrates. In this study, we explored the substrate promiscuity of microbial FADs and their ability to defluorinate polyfluorinated organic acids. Enzymatic screening of eight purified dehalogenases with reported fluoroacetate defluorination activity revealed significant hydrolytic activity against difluoroacetate in three proteins. Product analysis using liquid chromatography-mass spectrometry identified glyoxylic acid as the final product of enzymatic DFA defluorination. The crystal structures of DAR3835 from Dechloromonas aromatica and NOS0089 from Nostoc sp. were determined in the apo-state along with the DAR3835 H274N glycolyl intermediate. Structure-based site-directed mutagenesis of DAR3835 demonstrated a key role for the catalytic triad and other active site residues in the defluorination of both fluoroacetate and difluoroacetate. Computational analysis of the dimer structures of DAR3835, NOS0089, and RPA1163 indicated the presence of one substrate access tunnel in each protomer. Moreover, protein-ligand docking simulations suggested similar catalytic mechanisms for the defluorination of both fluoroacetate and difluoroacetate, with difluoroacetate being defluorinated via two consecutive defluorination reactions producing glyoxylate as the final product. Thus, our findings provide molecular insights into substrate promiscuity and catalytic mechanism of FADs, which are promising biocatalysts for applications in synthetic chemistry and bioremediation of fluorochemicals.

Proton transfer triggered in-situ construction of C=N active site to activate PMS for efficient autocatalytic degradation of low-carbon fatty amine

Removal of low-carbon fatty amines (LCFAs) in wastewater treatment poses a significant technical challenge due to their small molecular size, high polarity, high bond dissociation energy, electron deficiency, and poor biodegradability. Moreover, their low Brønsted acidity deteriorates this issue. To address this problem, we have developed a novel base-induced autocatalytic technique for the highly efficient removal of a model pollutant, dimethylamine (DMA), in a homogeneous peroxymonosulfate (PMS) system. A high reaction rate constant of 0.32 min−1 and almost complete removal of DMA within 12 min are achieved. Multi-scaled characterizations and theoretical calculations reveal that the in situ constructed C=N bond as the crucial active site activates PMS to produce abundant 1O2. Subsequently, 1O2 oxidizes DMA through multiple H-abstractions, accompanied by the generation of another C=N structure, thus achieving the autocatalytic cycle of pollutant. During this process, base-induced proton transfers of pollutant and oxidant are essential prerequisites for C=N fabrication. A relevant mechanism of autocatalytic degradation is unraveled and further supported by DFT calculations at the molecular level. Various assessments indicate that this self-catalytic technique exhibits a reduced toxicity and volatility process, and a low treatment cost (0.47 $/m3). This technology has strong environmental tolerance, especially for the high concentrations of chlorine ion (1775 ppm) and humic acid (50 ppm). Moreover, it not only exhibits excellent degradation performance for different amine organics but also for the coexisting common pollutants including ofloxacin, phenol, and sulforaphane. These results fully demonstrate the superiority of the proposed strategy for practical application in wastewater treatment. Overall, this autocatalysis technology based on the in-situ construction of metal-free active site by regulating proton transfer will provide a brand-new strategy for environmental remediation.

Extraction of scutched flax tow (SFT) in NHPI and PAG assisted H2O2 system in less water and low temperature environment

The extraction of flax fiber always consumed large amount of water and energy, and caused heavy Chemical oxygen demand (COD) discharge. Driven by the concept of green chemical and sustainable engineering, extracting flax fiber under less water environment and room temperature was necessary. This study conducted SFT degumming in nitroxide and H2O2 activating reagent aided alkali H2O2 (NAAH) system in less water environment under room temperature successfully. Results showed that N-Hydroxyphthalimide (NHPI) got much higher promoting effect in NAAH than that of 2,2,6,6-Tetramethylpiperidine 1-oxyl (TEMPO) due to its high bond dissociation energy value. HAR could brought up the selectivity of the NAAH system, and the promoting effect increased in the order of TAED > MA >AGC >PAG. With the assistance of PAG and NHPI, the degumming could be conducted under less water environment under room temperature. Under the optimal reaction condition (0.25 g/L NHPI, 2.5 g/L PAG, bath ratio 1:10, 30 °C, 2 h), the cellulose, hemicellulose and lignin content reached 82.19%, 10.82% and 1.74% respectively; the density, tenacity, DP value and whiteness reached 14 dtex, 78 cN/dtex, 2100 and 52.0 respectively. Compared with fiber prepared in NaOH degumming and alkali H2O2 degumming system, the fiber prepared in NAAH system get better tensile property; consumed 50% and 50% less water; 6.45 × 106 kcal/h and 5.16 × 106 kcal/h less energy, and produced 9.52% and 73.5% lower COD discharge, respectively.

Recent Advances in Electro- or Photochemical Driven Transformations via Cleavage of the C–N Bond of Quaternary Ammonium Salts

AbstractSelective functionalization via cleavage of the C–N bond of amines has proven to be challenging partly because of its relatively high bond dissociation energy, even though amines are abundant and readily available. To meet this challenge, many new transformations based on the pre-activation of the C–N bond before the cleavage have been developed. Among them, the conversion of amines into quaternary ammonium salts has certain advantages, such as easy preparation from primary, secondary, or tertiary amines, as well as stable storage and usage. Although transition metal catalysis has been frequently applied for developing new transformations via oxidative addition of the C–N bond of quaternary ammonium salts, recent studies have shown a new dimension by using green electro- or photochemical tools. In this short review, recent advances in electro-, photo-, or photoelectrochemical driven synthetic applications of quaternary ammonium salts have been summarized and discussed.1 Introduction2 Electrochemical Driven Transformations3 Photochemical Driven Transformations4 Photoelectrochemical Driven Transformations5 Conclusion and Outlook

Anti-Markovnikov hydrochlorination and hydronitrooxylation of α-olefins via visible-light photocatalysis

Conventional hydrofunctionalization of α-olefins with mineral acids proceeds with Markovnikov selectivity to afford branched isomers. The direct formation of linear constitutional isomers is challenging, yet anti-Markovnikov addition would be valuable for the synthesis of commodity chemicals, such as primary alcohols, which are currently only accessible via stoichiometric redox reactions, with a full equivalent of waste of both oxidant and reductant. Strategies that utilize radical intermediates have been demonstrated, but only for activated alkenes, and the direct use of aqueous mineral acids remains elusive. Here we present anti-Markovnikov addition reactions of aqueous hydrochloric and nitric acid to unactivated alkenes. The transformation is enabled by the in situ generation of photoredox-active ion pairs, derived from acridine and the mineral acid, as a combined charge- and phase-transfer catalyst. The introduction of a hydrogen atom transfer catalyst enabled us to bypass the challenging chain propagation by hydrochloric and nitric acids that originates from the high bond dissociation energy.

Screening Carbon-Boron Frustrated Lewis Pairs for Small-Molecule Activation including N2 , O2 , CO, CO2 , CS2 , H2 O and CH4 : A Computational Study.

Dinitrogen (N2 ) activation is particularly challenging under ambient conditions because of its large highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap (10.8 eV) and high bond dissociation energy (945 kJ mol-1 ) of the N≡N triple bond, attracting considerable attention from both experimental and theoretical chemists. However, most effort has focused on metallic systems. In contrast, nitrogen activation by frustrated Lewis pairs (FLPs) has been initiated recently via theoretical calculations. Here we perform density functional theory (DFT) calculations to screen a series of experimentally viable FLPs for small-molecule activation including N2 , O2 , CO, CO2 , CS2 , H2 O and CH4 . In addition, aromaticity is found to play an important role in most of these small-molecule activation. The particularly thermodynamic stabilities of the activation products and low reaction barriers could be a step forward for the development of FLP towards small-molecule activation including N2 , inviting experimental chemists' verification.

Compositional changes of CH, O, and N moieties in petroleum ether-extractable portions from the three-step mild degradation of Dongming lignite

Migration and distribution changes of CH, O, and N moieties in Dongming lignite (DL) derived petroleum ether-extractable portions (EPs), including cyclohexane (EPC), ethanol (EPE), and cyclohexane/ethanol (EPCE) systems were focused on in this work. Overall, EPC and EPE are rich in aromatics with short side-chains, while EPCE has the highest aromaticity. The gas chromatograph/mass spectrometer (GC/MS) analysis indicated that CH, >C-O-, and >C=O are three main parts. Alkanes in EPC are mainly concentrated in C11-C31 and the pristane/phytane ratio is 0.7, indicating the early anaerobic diagenesis of DL. Arenes are dominated by mono- to tricyclic compounds. The identification of these native compounds with low aromaticity implies the low coalification degree of DL. In addition, >C-O- and >C=O moieties predominate in EPE and EPCE. The differences in characteristic oxygenates, such as phenols and acetophenones, further indicated that ethanol involves in the cleavage of >Cal-O-Cal<, >Cal-O-Car<, and >Cal-Cal< bridged bonds in DL. GC/MS-undetectable oxynitrides, such as N1O1 and N2O1-4 species, were also discovered by Orbitrap MS. The compositional changes of O/N-containing species are related to source differences: (1) Step 1: the release of intrinsic fragments, (2) Step 2: the cleavage of weak O/N-containing covalent bonds, and (3) Step 3: the cleavage of covalent bonds with higher bond dissociation energies and the dissolution of macromolecules. The investigation on the changes of CH, O, and N moieties during the three-step mild degradation is beneficial to the secondary upgrading and value-added utilization of DL-derived soluble portions.

Enhanced Structural Stability and Capacity Retention of Ni-Rich LiNi0.91Co0.06Mn0.03O2 Cathode Material By Dual Doping and Coating for Libs

Nickel-rich layered cathode material has been received a lot of attention due to their superior cycle-ability, high energy density and improved safety. However, there are some issues which are needed to be resolved to ensure the long term application. The hostile attack of electrolyte with the charged cathode electrode results in the growth of thick solid electrolyte interphase (SEI) at the expense of Li+ consumption and increase in interfacial resistance. In addition, de/intercalation of Li+ leads to the continuous contraction and expansion of lattice structure that leads to the crack formation in the active material particles during extended cycling.In this work, a facile technique has been adopted to resolve the mentioned problems. In this study, Li3BO3 has been coated on the NCM surface to protect the active material against the continuous attack of electrolyte and boron is doped to enhance the structural stability of LiNi0.91Co0.06Mn0.03O2 NCM cathode material. The samples were characterized by XPS, XRD, SEM and TEM and the electrochemical properties were measured by assembling the coin cells. The XRD results confirm the shifting of (003) diffraction peak towards low angle which validates the boron doping in the crystal structure. The presence of B1s is confirmed on the surface of modified NCM by XPS analysis. The FETEM images shows a uniform and distinct coating layer of 12 nm on the surface of 0.05 wt% coated NCM. The 0.05 wt% NCM samples offers the highest discharge capacity of 215.3 mAh g-1 at 0.1C and capacity retention of 81.6% at 0.5C (1C = 202 mA g-1) after 100 cycles. The reason behind enhanced cycling is the high bond dissociation energy of B−O (ΔHf298 = 402 kJ mol−1) than Ni–O (ΔHf298 = 391.6 kJ mol−1), Co–O (ΔHf298 = 368 kJ mol−1) and even Mn–O (ΔHf298 = 402 kJ mol−1). Even at 2C cycling, LBO-0.05 NCM sample demonstrated a capacity retention of 79.4% after 100 cycles while pristine shows only 67.3%. The modified samples displayed superior rate performance as compare to pristine NCM, especially at high current density. The cyclic voltammetry and EIS results are in-line with the cycling data. The presence of B3+ doping in host structure and Li3BO3 coating on the NCM surface results in the superior electrochemical performance of modified NCM.

Tuning band structures of Hf-PCN-224(M) for β-Carbonyl C(sp3)-H bond activation and difunctionalization: Tandem C(sp3) radical cross-coupling through photoredox

The construction of C(sp3)-C(sp3) bonds by different C(sp3) radicals coupling reactions is still unexplored due to the high bond dissociation energy of C(sp3)-H bond and the difficulty for selective generating of C(sp3) radical. Benefiting from the precisely regulating for band structures of Hf-PCN-224(M), the β-carbonyl C(sp3)-H bonds are effectively oxidized by photo-generated holes to affording C(sp3) radicals in this work. C(sp3)-C(sp3) and C(sp3)-O bonds are constructed by tandem radical-radical cross-coupling, hydrogen atom transfer (HAT), and radical-radical cross-coupling between two C(sp3)-H bonds, enabling an effective C3-difunctionalization of indolin-2-ones under photo-thermo synergetic catalysis on Hf-PCN-224(Cu). Significantly, OH serves as triple roles: introduced hydroxyl group in situ, HAT abstractor and α-heteroatom for secondary activating C(sp3)-H bonds. Control experiments, EPR spectroscopy and DFT calculation provide insight into the tandem radicals cross-coupling mechanism. This operable strategy opens up a door for the difunctionalization of C(sp3)-H bonds in heterogeneous photoredox manner.

Understanding reaction mechanisms of metal-free dinitrogen activation by methyleneboranes

Dinitrogen activation under mild conditions is important but extremely challenging due to the inert nature of the NN triple bond evidenced by high bond dissociation energy (945 kJ/mol) and large HOMO-LUMO gap (10.8 eV). In comparison with largely developed transition metal systems, the reported main group species on dinitrogen activation are rare. Here, we carry out density functional theory calculations on methyleneboranes to understand the reaction mechanisms of their dinitrogen activation. It is found that the methyleneboranes without any substituent at the boron atom performs best on dinitrogen activation, which could be contributed to its small singlet-triplet gap. In addition, strong correlations are achieved on dinitrogen activation between the singlet-triplet energy gap and the reaction energies for the formation of the end-on products as well as the side-on ones. The principal interacting orbital analysis suggests that methyleneboranes can mimic transition metals to cleave the NN triple bond. Our findings could be helpful for experimental chemists aiming at dinitrogen activation by main group species.

The mechanism and rate constant of hydrogen transfer from solvent radicals to coal-based model compounds in direct coal liquefaction

In direct coal liquefaction, in addition to stabilizing coal radicals, the ability of solvent-derived cyclohexadienyl radicals to hydrolyze bridge bonds in coal is a part of their hydrogen-donating activity. In this work, the density functional theory calculations and transition state theory were employed quantitatively to analyze the rate constants of hydrogen transfer from solvent-derived cyclohexadienyl radicals to coal model compounds. Results indicated that polycyclic 9,10-dihydrophenanthrene, 4,5-dihydropyrene and 4,5,9,10-tetrahydropyrene radicals have higher hydrogenolysis ability, therefore they can promote the breakage of the Caryl–Calkyl bonds more effectively. There is no obvious correlation between the rate constants of hydrogen transfer from H-donors radicals to ipso-C of different coal model compounds and the dissociation enthalpies of Caryl–Calkyl bond. However, it can be found that model compounds with higher bond dissociation energies are more susceptible to hydrogenolysis by solvent-derived cyclohexadienyl radicals. Among the coal model compounds containing the same functional group, the coal model compounds with substituent groups directly attached to aromatic rings are more easily hydrolyzed by solvent-derived cyclohexadienyl radicals.

A practical fluorosulfonylating platform via photocatalytic imidazolium-based SO2F radical reagent

Sulfonyl fluorides are key components in the fields of chemical biology, materials science and drug discovery. In this line, the highly active SO2F radical has been employed for the construction of sulfonyl fluorides, but the utilization of gaseous ClSO2F as radical precursor is limited due to the tedious and hazardous preparation. Meanwhile, the synthesis of sulfonyl fluorides from inert SO2F2 gas through a fluorosulfonyl radical (·SO2F) process has met with inevitable difficulties due to the high homolytic bond dissociation energy of the S(VI)-F bond. Here we report a radical fluorosulfonylation strategy for the stereoselective synthesis of alkenyl sulfonyl fluorides and functional alkyl sulfonyl fluorides with an air-stable crystalline benzimidazolium fluorosulfonate cationic salt reagent. This bench-stable redox-active reagent offers a useful and operational protocol for the radical fluorosulfonylation of unsaturated hydrocarbons with good yield and high stereoselectivity, which can be further transformed into valuable functional SO2F moieties.

Maturation study of vitrinite in carbonaceous shales and coals: Insights from hydrous pyrolysis

The presence of vitrinite in sedimentary rocks of post-Silurian age allows its reflectance to be used to estimate the thermal maturation of organic matter in petroleum systems. Increasing reflectance of vitrinite, which is primarily driven by aromaticity, depends primarily on the time and temperature attributes of its evolutionary pathway. This study evaluated carbonaceous shales proximal to coal measures and coal samples via isothermal hydrous pyrolysis (HP) to compare differences in the maturation pathways of vitrinite. Sample residues were analysed via vitrinite reflectance (VRo), geochemical screening tests (organic carbon and programmed temperature pyrolysis), and infrared spectroscopy. The study included samples from Indian and North American basins, to observe differences in vitrinite evolution with respect to enclosing mineral matrix, starting degree of aromaticity, organic matter types, stratigraphic age, and depositional environment. The organic content of HP residues shows an intuitive response to the thermal stress of HP, e.g., a general depletion of total organic carbon (TOC) content, pyrolyzate (S2), and hydrogen index with increasing HP temperature. Infrared proxies including C-factor and CH2/CH3 generally decrease with increasing thermal maturity indicating loss of O via CO2 generation and the thermal cracking of aliphatic organic matter. Tmax, production index (PI), and VRo show intuitive increasing values with respect to HP temperature. The least mature sample (0.48 ± 0.05% VRo) generally experienced the maximum change in these parameters during maturation, whereas the most mature sample (0.99 ± 0.06% VRo) generally showed the least change. This observation is consistent with higher kinetic barriers to reaction in more aromatic vitrinite which contains higher bond dissociation energies. Devolatilization of vitrinite during HP causes formation of gas evacuation vacuoles and contraction cracks in the vitrinite grains of both coal and carbonaceous shale. Similarities in vitrinite response to HP between coal and carbonaceous shale suggest that thermal evolution of the vitrinite maceral is principally controlled by inherent rate-limiting kinetic parameters related to its molecular structure. Whereas, the stratigraphic age, sedimentary environment, surrounding organic matter, lithology, and catalysis by mineral composition have less effect. To further improve our understanding of vitrinite aromatization and kinetic parameters, future studies of vitrinite reflectance thermal evolution with temperature should include coal and carbonaceous shale from the same stratigraphic section and extant woody tissue from modern vascular plants.

A Fruitful Decade of Organofluorine Chemistry: New Reagents and Reactions

A Fruitful Decade of Organofluorine Chemistry: New Reagents and Reactions

Synergistic Pd/Cu-catalyzed enantioselective Csp2-F bond alkylation of fluoro-1,3-dienes with aldimine esters.

Due to high bond dissociation energies of Csp2–F bonds, using fluorinated compounds in Csp2–Csp3 cross-coupling is difficult. Here the authors report a protocol for enantioselective Csp2–Csp3 coupling of dienyl fluorides with aldimine esters, enabled by synergistic copper and palladium catalysis. This reaction represents the first example of asymmetric Csp2–Csp3 cross-coupling involving an inert Csp2–F bond and provides expeditious access to chiral α-alkenyl α-amino acids with high enantioselectivity. Control experiments suggest that the Csp2–F bond activation occurs through a pathway involving PdH migratory insertion and subsequent allylic defluorination, rather than by direct oxidative addition of the Csp2–F bond to Pd(0). The detailed mechanism is further investigated by DFT calculation and the enantioselectivity is rationalized.

Effect of Mn2+ doping on the lattice and the microwave dielectric properties of MgTa2O6 ceramics

A series of Mn2+-doped Mg1-xMnxTa2O6 (x = 0.02, 0.04, 0.06, 0.08, 0.10, 0.12) ceramics were synthesized by solid-state reaction method. The influence of introducing Mn–O bonds as a partial replacement for Mg–O bonds on the lattice and microwave dielectric properties was systematically investigated. XRD and Rietveld refinement confirm that Mn2+ occupies the 2a Wyckoff position and forms a pure trirutile phase. Moreover, based on the chemical bond theory, the dielectric constant is mainly affected by the ionicity of the Ta–O bond. The lattice and dielectric properties remain relatively stable with Mn2+ doping below 0.1, but excessive Mn2+ doping leads to pronounced distortion of the lattice, which is not beneficial for lattice stability and microwave dielectric properties. Introducing an appropriate amount of Mn–O bonds with high bond dissociation energy facilitates MgO6 octahedron stability, which improves the thermal stability of the lattice. Accordingly, the microwave dielectric properties for 0.06 Mn2+-doped MgTa2O6 ceramics were determined: εr = 28, Q × f = 105,000 GHz (at 7.5 GHz), τf = 19.5 ppm/°C.