Oxime Group Research Articles

Isomerism in Phenyl 2‐Pyridyl Ketoxime Metal Complexes

AbstractThe octahedral complex [RhCl2(ppkoH)(ppko)] (1) was obtained from the reaction between RhCl3 and phenyl 2‐pyridyl ketoxime (ppkoH). Attempts to prepare the corresponding octahedral platinum compound from K2PtCl6 gave instead the square planar [Pt2+(ppko)2] (2), but when the halogen was changed to bromine, the octahedral [Pt4+Br2(ppko)2] (3) was formed. The crystal structures were determined by X‐Ray crystallography. All the compounds have two N,N‐chelating oxime ligands. In 1, one of them is deprotonated, while in 2 and 3 both ligands are deprotonated. Compounds 1 and 3 have two halogen ligands in trans position. In 1 the oxime groups are situated mutually in cis position with an intramolecular hydrogen bond between the two N−O(H) groups. The formation of 2 involves reduction of the platinum metal and the complex has oximes in trans position to each other. Compound 3 has an all‐trans geometry. Since octahedral and square planar compounds have a possibility to isomerism, we studied the relative stability of different geometries by DFT calculations. A mixture of isomers is likely to be formed in the reactions, but the most stable form was found to crystallize. The properties of the electron density in the preferred isomers were also investigated via QTAIM methods.

Comparison of uranium complexes with methyl-glutarimidedioxime vs. glutarimidedioxime: A methyl change generates different consequences in thermodynamic equilibria and coordination modes

Nuclear power serves as an important source of alternative energy. However, land uranium resources are limited. In contrast, seawater contains an estimated total of 4.5 billion metric tons of uranium, which is more than a thousand times as much as that found in terrestrial ores. Therefore, developing techniques for uranium extraction from seawater is attracting research attention. Amidoxime-functionalized polymer fibers are the most widely utilized sorbents for this purpose. On the surface of amidoxime-based sorbents, cyclic glutarimidedioxime (H2A) is the preferred configuration for sequestration of uranium from seawater. Methyl-glutarimidedioxime (H2Q) forms if a methyl group attaches to the piperidine ring of H2A. The binding strength of uranyl complexes with H2Q and the enthalpy of complexation were investigated via potentiometry and microcalorimetry, respectively. The coordination mode was further revealed by single-crystal X-ray diffraction. It was expected that H2A and H2Q should be identical in terms of coordination as tridentate ligands. However, our investigation revealed that a methyl group attached to the piperidine ring not only altered the chelating mode but also lowered the binding strength of oxime groups. These findings show that developing a mechanism for optimizing molecules that would be formed on fiber surfaces remains challenging, even a methyl structural change would result in major consequences.

Halogenated monopyridinium oximes are less effective in reactivation of phosphylated cholinesterases than bisquaternary oximes

Mono-quaternary pyridinium oximes derived from K-oximes K027, K048 and K203 were designed, synthesized and evaluated for the reactivation of organophosphate-inhibited cholinesterases. The incorporation of the halogen atoms to the structure decreased the pKa value of the oxime group resulting in an increased formation of oximate necessary for reactivation. The stability and pKa values were found to be similar to analogous bis-quaternary compounds. Some mono-quaternary oximes resulted as relatively strong inhibitors of human acetylcholinesterase. Nevertheless, the reactivation ability of mono-quaternary oximes for organophosphate-inhibited cholinesterases was lower compared to their bis-quaternary analogues. These results were further confirmed by the determination of reactivation kinetics, when in some cases novel compounds showed improvement reactivation compared to the tested standards, but no improvement to bis-quaternary K-oximes. A computational study investigated reactivation process for K027, and its two analogues for VX-inhibited AChE. This study revealed slight differences between reactivation of mono-quaternary and bis-quaternary oximes.Abbreviations: 2-PAM, pralidoxime; AChE, acetylcholinesterase; ACN, acetonitrile; ATCI, acetylcholine iodide; BChE, butyrylcholinesterase; BTCI, butyrylcholine iodide; Bu3SnSnBu3, bis(tributyltin) Et2O, diethyl ether; ChEs, cholinesterases; CNS, central nervous system; DAD, diode array detector; DIBAL-H, diisobutylaluminium hydride; DMF, dimethylformamide; DMSO, dimethyl sulfoxide; DTNB, 5,5́-dithiobis-2-nitrobenzoic acid; Et3N, triethylamine; EtOAc, ethyl acetate; EWG, electron withdrawing group; HI-6, asoxime; hrAChE, human recombinant acetylcholinesterase; hrBChE, human recombinant butyrylcholinesterase; hrChEs, human recombinant cholinesterases; HPLC, high-performance liquid chromatography; HRMS, high-resolution mass spectrometry; KD, dissociation constant; kr, first-order reactivation rate constant; kr2, second-order reactivation rate constant; LüH-6, obidoxime; MeOH, methanol; MM, molecular mechanics; MMC-4, methoxime; m.p., melting point; NCIs, non-covalent interactions; NEDPA, 4-nitrophenyl ethyl dimethylphosphoramidate; NEMP, 4-nitrophenyl ethyl methylphosphonate; NIMP, isopropyl methylphosphonate; NMR, nuclear magnetic resonance spectroscopy; OPs, organophosphates; PBS, phosphate-buffered saline; Pd(dppf)Cl2.CH2Cl2, [1,1′-Bis(diphenylphosphino)ferrocene]dichloropalladium(II) in complex with dichloromethane; pKa, negative decimal logarithm of the dissociation constant; POX, paraoxon; PPh3, triphenylphosphine; QM, quantum mechanics; rt, room temperature; SN2, bimolecular nucleophilic substitution; SNAc, nucleophilic acyl substitution; THF, tetrahydrofuran; TMC-4, trimedoxime; TNB, 5-thio-2-nitrobenzoic acid; UHPLC, ultra high-performance liquid chromatography; UV, ultraviolet; UV–VIS, ultraviolet–visible.

Synthesis of Long‐Chain Polyamides via Main‐Chain Modification of Polyethyleneketones

AbstractLong‐chain polyamides (polyethyleneamides) were prepared from polyethylenes bearing in‐chain carbonyl groups (polyethyleneketones) by the oxime formation and successive Beckmann rearrangement. (Diethylamino)sulfur trifluoride (DAST) was utilized as a promoter, which allowed mild conversion of the oxime group in spite of low solubility of the polymers. The polyethyleneamide exhibited different tensile property compared to a commercial HDPE.

Experimental and Computational Investigation of Salicylhydroxamic Acid as a Corrosion Inhibitor for Copper in Alkaline Solutions

Inhibitors, as indispensable components in chemical mechanical polishing (CMP) slurries, have a significant impact on inhibiting copper (Cu) corrosion and enhancing post-polishing surface quality. However, one of the major challenges in CMP lies in unraveling the microscopic corrosion inhibition mechanism of Cu. This work focuses on investigating the impact of an inhibitor, salicylhydroxamic acid (SHA), on the static etching rate (SER), electrochemical parameters, and surface morphology of Cu. The experimental findings demonstrate that SHA significantly decreases the SER and corrosion current density of Cu, while notably improving the Cu surface quality. The corrosion inhibition mechanisms of SHA on Cu are revealed through adsorption isotherm models, contact angle analysis, electrochemical impedance spectroscopy, and computational chemistry method. The benzene ring, oxime group, and O1 atom of SHA exhibit significant chemical reactivity, facilitating the preferential adsorption of SHA on Cu in a parallel orientation, thereby forming a hydrophobic protective film on the Cu surface. This process hinders the interaction between corrosive solutions and Cu, therefore SHA exhibits excellent corrosion inhibition performance on Cu. These findings hold great importance in gaining a deeper comprehension of the corrosion inhibition process of Cu, and provide guidance for designing more efficient inhibitors.

Design, synthesis, and biological evaluation of imidazolylacetophenone oxime derivatives as novel brain-penetrant agents for Alzheimer's disease treatment

Alzheimer's disease (AD, also known as dementia) has become a serious global health problem along with population aging, and neuroinflammation is the underlying cause of cognitive impairment in the brain. Nowadays, the development of multitarget anti-AD drugs is considered to be one effective approach. Imidazolylacetophenone oxime ethers or esters (IOEs) were multifunctional agents with neuroinflammation inhibition, metal chelation, antioxidant and neuroprotection properties against Alzheimer's disease. In this study, IOEs derivatives 1−8 were obtained by structural modifications of the oxime and imidazole groups, and the SARs showed that (Z)-oxime ether (derivative 2) had stronger anti-neuroinflammatory and neuroprotective ability than (E)-congener. Then, IOEs derivatives 9−30 were synthesized based on target-directed ligands and activity-based groups hybridization strategy. In vitro anti-AD activity screening revealed that some derivatives exhibited potentially multifunctional effects, among which derivative 28 exhibited the strongest inhibitory activity on NO production with EC50 value of 0.49 μM, and had neuroprotective effects on 6-OHDA-induced cell damage and RSL3-induced ferroptosis. The anti-neuroinflammatory mechanism showed that 28 could inhibit the release of pro-inflammatory factors PGE2 and TNF-α, down-regulate the expression of iNOS and COX-2 proteins, and promote the polarization of BV-2 cells from pro-inflammatory M1 phenotype to anti-inflammatory M2 phenotype. In addition, 28 can dose-dependently inhibit acetylcholinesterase (AChE) and Aβ42 aggregation. Moreover, the selected nuclide [18F]-labeled 28 was synthesized to explore its biodistribution by micro-PET/CT, of which 28 can penetrate the blood-brain barrier (BBB). These results shed light on the potential of 28 as a new multifunctional candidate for AD treatment.

The Effective Separation of Gallium, Vanadium, and Aluminum from a Simulated Bayer Solution by Resin Exchange.

The effective recovery of gallium from wastewater discharge in the Bayer process is promising for the long-term development of gallium resources. The adsorption and desorption behavior of gallium (Ga), vanadium (V), and aluminum (Al) ions on a strong acidic styrene cation exchange resin (JK resin) from a simulated Bayer solution was systematically investigated by static experiments. The results showed that the optimum conditions for separating Ga from V and Al were at low temperatures and short contact times, with 78.30%, 15.16%, and 6.63% of the adsorption efficiency at 25 °C and 60 min, respectively, for Ga, V, and Al. The adsorption kinetics of Ga3+ conformed to the pseudo-second order model, and the static saturation adsorption capacity was 18.25 mg/g. The Langmuir model fitted the adsorption isotherm of gallium well, and the maximum adsorption capacity was 1.11 mg/g at 25 °C. FT-IR spectroscopy and XPS showed that the mechanism of the Ga3+ adsorption was only related to the interaction of the oxygen atoms of the amide oxime group (C=NOH). The separation of Ga, V, and Al can be achieved by desorbing 98% of Al with low concentrations of ammonia and 90% of Ga with low concentrations of hydrochloric acid. The results indicate that JK resin is an efficient adsorbent for separating gallium and vanadium in alkaline solutions.

Synthesis of steroid tracers with a oxyme ligation method and use thereof in fluorescent polarisation immunoassay

A method for the synthesis of ketosteroid oxime conjugates with a fluorescein (6-FAM) derivative connected via a short bifunctional aminooxypropyl linker is proposed. The conjugates were used as tracers for fluorescence polarization immunoassay (FPIA) with monoclonal antibodies. Stereoisomers by the oxime group were separated by preparative RP TLC and HPLC and tested in the FPIA method. Binding parameters of of tracers with monoclonal antibodies (mAbs) to progesterone were studied. Tracers showed high efficiency in the analysis of steroid hormones, the detection limit of progesterone being lower than that for a previously described analog. The Z-isomer was found to be more sensitive in the FPIA analysis compared to the E-isomer.

Enhanced simultaneous adsorption and detection of mercury (II) using functionalized metal − organic framework with defect structures

Designing adsorption materials with high selectivity and sensitive detection is crucial for heavy metal removal. In this study, we introduced thiol, oxime, and thiourea functional groups, containing S, N, or both N and S elements, into the metal − organic framework (MOF-808, Zr6O4(OH)4(H3BTC)2(HCOO)6) to enhance its adsorption and detection capabilities for Hg2+. Moreover, by carefully controlling the molar ratio of the metal source, tricarboxyl and monocarboxyl ligands, we tailored the defects of MOF-808. The thiourea-modified materials demonstrated a record-breaking adsorption capacity (957.94 mg·g−1, 1.99 times that of unmodified materials) and distribution coefficient (743333 mL·g−1) for Hg2+, substantially exceeding that of other ions (separation factor of 105,086 for Hg2+/Zn2+). The material also showed excellent recoverability during ten consecutive cycles in Hg2+ adsorption. Furthermore, the modified MOF-808 displayed selective detection for Hg2+ with a high photochemical quenching coefficient (Ksv = 156.0 M−1). Theoretical calculations indicate that the thiourea group of MOF-808 favors the energetically advantageous Hg2+ capture and detection. These findings underscore the significance of MOF modification and defects engineering as vital strategies for optimizing the simultaneous removal and detection of heavy metal ions.

Synthesis of Long-Chain Polyamides via Main-Chain Modification of Polyethyleneketones.

Long-chain polyamides (polyethyleneamides) were prepared from polyethylenes bearing in-chain carbonyl groups (polyethyleneketones) by the oxime formation and successive Beckmann rearrangement. (Diethylamino)sulfur trifluoride (DAST) was utilized as a promoter, which allowed mild conversion of the oxime group in spite of low solubility of the polymers. The polyethyleneamide exhibited different tensile property compared to a commercial HDPE.

Microscopic growth of pyridinium oxime based amphipathic on graphite: Effect of relative position of substituents

AbstractAmphipathic molecules with surfactant like properties have several applications ranging from healthcare to the chemical industry. Their ability to form thin films on surfaces with ordered and controllable patterns determines their applicability. Here, we report two pyridinium oxime‐based surfactants, which possess similar aggregation properties in solution, but exhibit substantially different assembly on highly oriented pyrolytic graphite (HOPG) surface. The two compounds are regioisomers with the oxime unit placed either in meta or para position of the pyridinium ring. While the para isomer assembled to anisotropic one‐dimensional (1D) islands and long rod‐like structures, the meta isomer formed two‐dimensional (2D) islands on the HOPG surface. This difference is rationalized through molecular level force‐field calculations that show anisotropy in the growth of the para isomer resulting from an effective overlap of the alkyl chains and oxime groups, which is distinctly not feasible in the assembly of the meta isomer. The assembly of these compounds is compared with another oxime‐containing compound of similar structure, but without the charged pyridinium unit. The charged unit seems to be crucial for the preferential formation of multilayer islands even at low coverage.

A Zn(II) Coordination Polymer for Fluorescent Turn-Off Selective Sensing of Heavy Metal Cation and Toxic Inorganic Anions.

A novel coordination polymer [Zn(atyha)2]n (1) (Hatyha = 2-(2-aminothiazole-4-yl)-2- hydroxyiminoacetic acid) was constructed by hydrothermal reaction of Zn2+ with Hatyha ligand. CP 1 exhibits a 2D (4,4)-connected topological framework with Schläfli symbol of {44·62}, where atyha- anions serve as tridentate ligands, bridging with Zn2+ through carboxylate, thiazole and oxime groups. CP 1 displays a strong ligand-based photoluminescence at 390 nm in the solid state, and remains significantly structurally stable in water. Interestingly, it can be utilized as a fluorescent probe for selective and sensitive sensing of Fe3+, Cr2O72- and MnO4- through the fluorescent turn-off effect with limit of detection (LOD) of 3.66 × 10-6, 2.38 × 10-5 and 2.94 × 10-6 M, respectively. Moreover, the efficient recyclability for detection of Fe3+ and Cr2O72- is better than that for MnO4-. The mechanisms of fluorescent quenching involve reversible overlap of UV-Vis absorption bands of the analytes (Fe3+, Cr2O72- and MnO4-) with fluorescence excitation and emission bands for CP 1, respectively.

Synthesis and utilization of a novel amidoxime collector for the flotation separation of cuprite from calcite

In this study, a novel copper oxide flotation collector, p-methylphenylethyl amide oxime (PEBH), was synthesized via the nitrile–hydroxylamine method, and the flotation behavior of cuprite and calcite under this collector system was studied. The oxime groups of the collector provided additional action sites to form stable chelates with metal ions. The performance of PEBH in cuprite ore flotation was investigated via contact angle measurement, zeta potential measurement, Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and calculations based on the EDLVO (extended Derjaguin, Landau, Verwey, and Overbeek) theory. The flotation experiments of single minerals and artificial mixed minerals indicated that PEBH has excellent flotation ability. At pH 11 and PEBH concentration of 2 × 10−4 mol/L, the cuprite recovery is as high as 96.84 %. Under alkaline conditions of pH 9.0 and 11.0, it can effectively separate cuprite from calcite. Contact angle measurements showed that PEBH significantly enhanced the surface hydrophobicity of cuprite. Zeta potential, FTIR spectroscopy, and XPS analyses revealed the selective chemical adsorption of PEBH onto the Cu sites of cuprite. The results of EDLVO theory-based calculations further confirmed after PEBH action, the attraction between cuprite and bubbles significantly increased, which is beneficial to cuprite flotation. Overall, the results demonstrate that PEBH is a potential collector for the flotation separation of cuprite from calcite.

Oxime chemistry in crop protection.

An overview is given on the significance of the oxime moiety in crop protection chemistry. This review focuses on the two most important aspects of agrochemical oximes, which are the occurrence and role of oxime groups in compounds with herbicidal, fungicidal and insecticidal activity, as well as the application of oxime derivatives as intermediates in the synthesis of crop protection agents not bearing any oxime function. Especially noteworthy is the fact, that in the synthesis of agrochemicals, oximes can be cyclized to isooxazoline, isoxazole, oxadiazole, oxazine, pyrrole, isothiazole and imidazole rings. © 2024 Society of Chemical Industry.

Hybrid copper-polyelectrolyte nanoaggregates obtained with smart block copolymers based on 4-[(hydroxyimino)aldehyde]butyl methacrylate (HIABMA) in water and acetonitrile

The AB multi-stimuli-responsive block copolymer pTEGMA-b-pHIABMA (TEGMA: tetra(ethyleneglycol) methyl ether methacrylate; HIABMA: 4-[(hydroxyimino)aldehyde]butyl methacrylate) comprises a hydrophilic and thermoresponsive PTEGMA block linked to the hydrophobic PHIABMA chain. The latter is endowed with slightly acidic oxime groups that potentially form complexes with metal ions. Here we investigate the formation of hybrid Cu(II)-polymer nanoaggregates both in water and in acetonitrile. Cu(II) ions are quantitatively and rapidly incorporated, in the presence of a base, into pre-formed polymeric core-shell micelles (30 nm diameter by DLS) in water up to 1:2 metal-to-ligand stoichiometry. The pKa of the polymer is decreased from ≅11.2 to 4.65 due to interaction with Cu(II) and the complex is shown to involve oximate ions. The thermoresponsivity of the polymeric micelles remains unchanged with Cu(II) complexation and allows an easy separation by flocculation of the hybrid complex. Moreover, nanoaggregates (D = 20 nm) form in acetonitrile from the fully solubilized copolymer interacting with Cu(OAc)2. The 1:2 Cu(II)/ligand stoichiometry is confirmed with the Job graphical method. Characterization of the hybrid micelles was carried out by UV–Vis spectrometry, DLS, TEM, STEM and SAXS. Quantitative release of Cu(II) in acidic conditions is demonstrated both in water and in acetonitrile. Full recovery of the free metal ions and of intact polymeric micelles is achieved through centrifugal filtration of the aqueous preparation, as a proof-of-concept for a recyclable system for metal uptake and release. Furthermore, Cu0 nanoparticles of 5–10 nm are obtained through reduction of Cu(II) within the micelles with ascorbic acid in aqueous solution.

Cholesterol Oxime Olesoxime Assessed as a Potential Ligand of Human Cholinesterases.

Olesoxime, a cholesterol derivative with an oxime group, possesses the ability to cross the blood-brain barrier, and has demonstrated excellent safety and tolerability properties in clinical research. These characteristics indicate it may serve as a centrally active ligand of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), whose disruption of activity with organophosphate compounds (OP) leads to uncontrolled excitation and potentially life-threatening symptoms. To evaluate olesoxime as a binding ligand and reactivator of human AChE and BChE, we conducted in vitro kinetic studies with the active metabolite of insecticide parathion, paraoxon, and the warfare nerve agents sarin, cyclosarin, tabun, and VX. Our results showed that both enzymes possessed a binding affinity for olesoxime in the mid-micromolar range, higher than the antidotes in use (i.e., 2-PAM, HI-6, etc.). While olesoxime showed a weak ability to reactivate AChE, cyclosarin-inhibited BChE was reactivated with an overall reactivation rate constant comparable to that of standard oxime HI-6. Moreover, in combination with the oxime 2-PAM, the reactivation maximum increased by 10-30% for cyclosarin- and sarin-inhibited BChE. Molecular modeling revealed productive interactions between olesoxime and BChE, highlighting olesoxime as a potentially BChE-targeted therapy. Moreover, it might be added to OP poisoning treatment to increase the efficacy of BChE reactivation, and its cholesterol scaffold could provide a basis for the development of novel oxime antidotes.

Large stokes shift and near-infrared fluorescent probe for bioimaging and evaluating the HClO in an rheumatoid arthritis mouse model

It is crucial to identify aberrant HClO levels in living things since they pose a major health risk and are a frequent reactive oxygen species (ROS) in living organisms. In order to detect HClO in various biological systems, we created and synthesized a near-infrared fluorescent probe with an oxime group (−C = N-OH) as a recognition unit. The probe DCMP1 has the advantages of fast response (10 min), near-infrared emission (660 nm), large Stokes shift (170 nm) and high selectivity. This probe DCMP1 not only detects endogenous HClO in living cells, but also enables further fluorescence detection of HClO in living zebrafish. More importantly, it can also be used for fluorescence imaging of HClO in an rheumatoid arthritis mouse model. This fluorescent probe DCMP1 is anticipated to be an effective tool for researching HClO.

Construction of β-Oximino Phosphorodithioates via (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl-Promoted Difunctionalization of Alkenes with tert-Butyl Nitrite, P4S10, and Alcohols.

A (2,2,6,6-tetramethylpiperidin-1-yl)oxyl-mediated difunctionalization of alkenes with tert-butyl nitrite, P4S10, and alcohols has been developed for the synthesis of β-oximino phosphorodithioates. The reaction goes through a radical pathway with the successive installation of phosphorodithioate and an oxime group. This four-component protocol offers a practical approach to constructing a variety of β-oximino phosphorodithioates in moderate to good yields with favorable functional group tolerance.

Asymmetric Tandem Michael Addition/Interrupted Nef Reactions of Nitromethane with Oxindole-Derived Alkenes: Enantioselective Synthesis of Spiro-polycyclic Oxindoles.

Chiral spiro-polycyclic oxindoles are valuable heterocyclic ring systems that are widely distributed in natural alkaloids and biologically active compounds. Herein, we reported an asymmetric tandem Michael addition/interrupted Nef reaction of nitromethane with oxindole-derived alkenes catalyzed by a chiral 2-aminobenzimidazole bifunctional organocatalyst. A series of novel enantiomerically enriched spiro-polycyclic oxindole derivatives bearing an oxime group were synthesized in moderate to excellent isolated yields (up to 99%) with an excellent level of enantioselectivities (up to 99% ee). Furthermore, the antiproliferation activity of the resulting oxindoles derivatives were evaluated, and compound 2d demonstrated promising anticancer properties against HCT116 (IC50 = 14.08 μM) and HT29 (IC50 = 15.46 μM) cell lines.

5-methyl-salicylaldoxime based ionic liquids for non-destructive separation of protein and cadmium

Confronting with explosive cadmium contaminations to environment, non-destructive separation of protein with cadmium for protecting food safety is hardpressed. Ionic liquids (ILs) are benign bio-compatible stabilizer of proteins with considerable metal affinity, while their application in separation of cadmium from protein is limited owing to their comparative metal affinities with protein. Accordingly, we firstly synthesize 1-methyl-3 (salicylaldoxime-5-methyl) imidazole hexafluorophosphate ([Salenmim][PF6]) to enhance cadmium extraction with hydroxyl and oxime groups as ligands of cadmium. Structure of [Salenmim][PF6] is confirmed by 1H NMR, 13C NMR, 31P NMR, 19F NMR, FT-IR, Raman spectra, and theoretical simulations. [Salenmim][PF6] can remove 85.31 % of Cd2+ from bovine serum albumin (BSA) at pH of 2.0. X-ray photoelectron spectroscopy (XPS) of BSA and [Salenmim][PF6] before and after Cd2+ extraction illustrate that Cd2+ generally bonds with C = N and O-H of [Salenmim][PF6] to achieve detachment of Cd2+ from BSA. Molecular docking of BSA and Cd2+ indicates that 4 amino acids residues listed as ASP561, ASP562, LYS563, and GLU564 coordinate with Cd2+ with coordinate number close to 1, further confirmed as 1.48 by isothermal titration calorimetry (ITC) analysis. DFT calculations of [Salenmim][PF6] with Cd2+ demonstrate that energy gap between HOMO orbital localized at benzene ring is 1.6860 eV higher than LUMO orbital, faciliating formation of [Salenmim][PF6]-Cd2+ complex. Finally, there are no changes in secondary and tertiary structure of BSA and no ILs residual observed after [Salenmim][PF6] assisted Cd2+ extraction. This work firstly reports a method for synthesis of [Salenmim][PF6] with high affinity to cadmium and systemically reveals how do structure of [Salenmim][PF6] enhance heavy metal removal from proteins, providing a possible strategy for heavy metal extraction from proteins.