Malonate Ion Research Articles

Stereospecific Ligands and Their Complexes. III. Oxalato and Malonato-(ethylenediamine-N,N′-di-S,S-2-propionato)-Chromate(III) Complexes. Crystal Structure of the Δ-(–)589-s-cis-K[Cr(S,S-eddp)(ox)] · 0.5H2O

The s-cis-[Cr(S,S-eddp)L]− complexes (S,S-eddp = S,S-ethylenediamine-N,N′-di-2-propionate ion; L = oxalate or malonate ions) were prepared. The complexes were purified by ion-exchange chromatography. The geometry of the complexes has been supposed on the basis of the electronic absorption spectra, and the absolute configurations of the isolated s-cis-[Cr(S,S-eddp)L]− complexes have been predicted on the basis of their circular dichroism (CD) spectra and confirmed by X-ray analysis of the crystal structure of the Δ-(–)589-s-cis-K[Cr(S,S-eddp)(ox)] 0.5H2O complex. The title compound, s-cis-potassium-(ethylenediamine-N,N’-di-S,S-2-propionato) (oxalato)chromate(III) semihydrate was synthesized by passing the corresponding sodium salt through cation exchange-resin Merck I in potassium form and its crystal structure determined. Single crystal X-ray diffraction analysis reveals s-cis geometry of the complex cation.

Cluster Phase Chemistry: Collisions of Vibrationally Excited Cationic Dicarboxylic Acid Clusters with Water Molecules Initiate Dissociation of Cluster Components

A homologous series of cationic gas-phase clusters of dicarboxylic acids (oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid) generated via electrospray ionization (ESI) are investigated using collision-induced dissociation (CID). Singly charged cationic clusters with the composition (Na(+))(2n+1)(dicarboxylate(2-))(n), where n = 1-5, are observed as major gas-phase species. Significant abundances of singly charged sodiated hydrogen dicarboxylate clusters with the composition (Na(+))(2n)(dicarboxylate(2-))(n)(H+), where n = 1-6, are observed with oxalic acid, malonic acid, and succinic acid. Isolation of the clusters followed by CID results mainly in sequential loss of disodium dicarboxylate moieties for the clusters of succinic acid, glutaric acid, and adipic acid. However, the dimer of sodiated hydrogen succinate, all malonate clusters, and all oxalate clusters, with the exception of the dimer, exhibit complex chemical reactions initiated by the collision of vibrationally excited clusters with water molecules. Generally, water molecules serve as proton donors for reacting dicarboxylate anions in the cluster, initiating dissociation pathways such as the decomposition of the malonate ion to yield an acetate ion and CO(2). The reactivity of several mixed dicarboxylate clusters is also reported. For example, malonate anion is shown to be more reactive than oxalate anion for decarboxylation when both are present in a cluster. The energetics of several representative cluster phase reactions are evaluated using computational modeling. The present results for cationic clusters are compared and contrasted to earlier studies of anionic sodiated dicarboxylic acid clusters.

Crystal structure of barium α-(Ethylenediamine-N,N-diacetato)malonatocobaltate(III) perchlorate pentahydrate Ba[Co(Edda)(Mal)(ClO4) · 5H2O

The crystal structure of [Co (Edda)(Mal)](ClO4) · 5H2O is determined by X-ray diffraction analysis (the crystals are triclinic: a = 10.1363(12) A, b = 11.0801(13) A, c = 11.3173(13) A, α = 101.129(13)°, β = 108.594(13)°, γ = 112.883(13)°, Z = 2, space group P \(\overline 1 \)). The Co3+ ion coordinates two O atoms of the malonate ion, as well as two N atoms and two trans-O atoms of the ethylene-N,N-diacetate ion. The [(H2O)4Ba(ClO4)]+ subunits interact with the [Co(Edda)(Mal)]− complexes to form infinite ribbons, and each complex is bonded with three Ba atoms through the O atoms of the carboxyl groups. The coordination number of the Ba atom is nine (four O atoms of the water molecule, one O atom of the perchlorate ion, and four O atoms of three adjacent complexes).

New molybdenum(V) complexes based on the {Mo 2O 4} 2+ structural core with esters or anions of malonic and succinic acid

A series of malonato complexes of molybdenum(V) was prepared by reacting (PyH) 5[MoOCl 4(H 2O)] 3Cl 2 or (PyH) n [MoOBr 4] n with malonic acid (H 2mal) or a half-neutralized acid, hydrogen malonate (Hmal −), at ambient conditions: (PyH) 3[Mo 2O 4Cl 4(μ 2-Hmal)] · CH 3CN ( 1), (PyH) 3[Mo 2O 4Br 4(μ 2-Hmal)] · CH 3CN ( 2), (PyH) 2[Mo 2O 4Cl(η 2-mal)(μ 2-Hmal)Py] ( 3), (3,5-LutH) 2(H 3O) [Mo 2O 4(η 2-mal) 2(μ 2-Hmal)] ( 4), (PyH)[Mo 2O 4Cl 2(μ 2-Memal)Py 2] ( 5), (3,5-LutH)[Mo 2O 4Cl 2(μ 2-Memal)(3,5-Lut) 2] ( 6), (PyH)[Mo 2O 4Cl 2(μ 2-Etmal)Py 2] ( 7), (3,5-LutH)[Mo 2O 4Cl 2(μ 2-Prmal)(3,5-Lut) 2] ( 8) and [{Mo 2O 4(μ 2-Memal)Py 2} 2(μ 2-OCH 3) 2] ( 9) (where Py = pyridine, C 5H 5N; PyH + = pyridinium cation, C 5H 5NH +; 3,5-Lut = 3,5-lutidine, C 7H 9N; 3,5-LutH + = 3,5-lutidinium cation, C 7H 9NH +; mal 2− = malonate, −OOCCH 2COO −; Memal − = monomethyl malonate, −OOCCH 2COOCH 3; Etmal − = monoethyl malonate, −OOCCH 2COOC 2H 5 and Prmal − = monopropyl malonate, −OOCCH 2COOC 3H 7). The complex anions of compounds 1– 8 have a common structural feature: a dinuclear, singly metal–metal bonded {Mo 2O 4} 2+ core with the carboxylate moiety of the malonato ligand coordinated in a syn– syn bidentate bridging manner to the pair of metal atoms. The remaining four coordination sites of the {Mo 2O 4} 2+ core are occupied with halides in 1 and 2, with halides/pyridine ligands in 5– 8, with a pair of bidentate malonate ions in 4 and with the combination of all in 3. The neutral molecules of 9 consist of two {Mo 2O 4} 2+ cores linked with a pair of methoxide ions into a chain-like, tetranuclear cluster. An esterification of malonic acid was observed to take place in the reaction mixtures containing alcohols. Solvothermal reactions with malonic acid carried out at 115 °C produced anionic acetato complexes as found in (PyH)[Mo 2O 4Cl 2(μ 2-OOCCH 3)Py 2] · Py ( 10), (PyH)[Mo 2O 4Cl 2(μ 2-OOCCH 3)Py 2] ( 11), (3,5-LutH)[Mo 2O 4Cl 2(μ 2-OOCCH 3)(3,5-Lut) 2] ( 12) and (4-MePyH) 3[Mo 2O 4Cl 2(μ 2-OOCCH 3)(4-MePy) 2] 2Cl ( 13) (4-MePy = 4-methylpyridine, C 6H 7N). The acetate coordinated in the syn– syn bidentate bridging mode in all. Reactions of (PyH) 5[MoOCl 4(H 2O)] 3Cl 2 with succinic acid (H 2suc) at ambient conditions resulted in a complex with a half-neutralized acid, (PyH)[Mo 2O 4Cl 2(μ 2-Hsuc)Py 2] · Py ( 14) (Hsuc − = hydrogen succinate, −OOC(CH 2) 2COOH), while those carried out at 115 °C in a tetranuclear succinato complex, (4-MePyH) 2[{Mo 2O 4Cl 2(4-MePy) 2} 2(μ 4-suc)] ( 15) (suc 2− = succinate, −OOC(CH 2) 2COO −). The tetranuclear anion of 15 consists of two {Mo 2O 4} 2+ cores covalently linked with a tetradentate succinato ligand. The compounds were fully characterized by infrared vibrational spectroscopy, elemental analyses and X-ray diffraction studies.

Crystal chemical role of oxalate and malonate ions

Crystal chemical role of oxalate and malonate ions

The interplay of hydrogen-bonding and metal-coordination motifs in the formation of supramolecular patterns: Copper/zinc malonates–aminopyrimidine complexes

The X-ray crystal structures of 1 [2[AMPYH] · [(Cu (H 2O) (mal) 2)]:2H 2O] and 2 [2[AMPYH] · [ZnBr (Hmal) (mal)]:2H 2O ] [mal = malonate; Hmal = hydrogen malonate; AMPYH = 2-amino-4, 6-dimethylpyrimidinium] reveal the interplay of metal-coordination motifs and the hydrogen-bonding patterns . In both the structures, the 2-amino-4,6-dimethylpyrimidine cations are not directly coordinated to copper and zinc, but are hydrogen-bonded to the malonate ion. The protonated endocyclic nitrogen and the amino group of 2-amino-4,6-dimethylpyrimidine molecule interact with malonate ligand via a pair of N–H⋯O hydrogen-bonds, (with graph set notation R 2 2 ( 8 ) ) whereas the unprotonated endocyclic nitrogen and the amino group interact with the malonate ligand via N–H..O and C–H⋯N hydrogen-bonds forming the same R 2 2 ( 8 ) motif. The combination of hydrogen-bonding motif and metal-coordination motif creates a novel supramolecular motif. The interplay of the hydrogen-bonding motif and metal-coordination motif via hydrogen-bonds leads to similar supramolecular motifs in both the structures.

Synthesis and crystal structure of two metal complexes involving reduced imino nitroxides

Two novel complexes, [Co(mal)(IMH2py)2]ClO4 (1) and [Mn(mal)(IMH2py)2] · H2O (2), have been synthesized and their crystal structures determined by X-ray diffraction methods. The imino nitroxide 1-oxy-2-(2′-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole (IM2py) is reduced during reaction to yield 1-hydroxy-2(2′-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole (IMH2py); mal is the malonate anion. Complexes 1 and 2 crystallize in the monoclinic space group C2 space group with a = 17.004(9), b = 10.753(5), c = 9.207(5) Å, β = 113.856(8)° and Z = 2 for 1, and a = 16.721(5), b = 10.897(5), c = 9.253(3) Å, β = 120.807(6)° and Z = 2 for 2. Each metal ion is six-coordinated by two imino nitrogen atoms of two iminohydroxylamine groups, two nitrogen atoms of two pyridyl groups and two oxygen atoms of the malonate ion.

Bonding energetics in clusters formed by cesium salts: a study by collision‐induced dissociation and density functional theory

In relation to the interaction between (137)Cs and soil organic matter, electrospray mass spectrometry experiments and density functional theory (DFT) calculations were carried out on the dissociation of positively charged adducts formed by cesium nitrate and cesium organic salts attached to a cesium cation [Cs(CsNO(3))(CsA)](+) (A = benzoate, salicylate, hydrogen phthalate, hydrogen maleate, hydrogen fumarate, hydrogen oxalate, and hydrogen malonate ion). These mixed clusters were generated by electrospray from methanol solutions containing cesium nitrate and an organic acid. Collision-induced dissociation of [Cs(CsNO(3))(CsA)](+) in a quadrupole ion trap gave [Cs(CsNO(3))](+) and [Cs(CsA)](+) as major product ions. Loss of HNO(3) was observed, and also CO(2) loss in the case of A = hydrogen malonate. Branching ratios for the dissociation into [Cs(CsNO(3))](+) and [Cs(CsA)](+) were treated by the Cooks' kinetic method to obtain a quantitative order of bonding energetics (enthalpies and Gibbs free energies) between Cs(+) and the molecular salt (ion pair) CsA, and were correlated with the corresponding values calculated using DFT. The kinetic method leads to relative scales of Cs(+) affinities and basicities that are consistent with the DFT-calculated values. This study brings new data on the strong interaction between the cesium cation and molecular salts CsA.

The thermodynamic characteristics of complex formation between vanadium(V) and malonic acid

Coordination and protolytic equilibria in the system vanadium(V)-malonic acid were studied calorimetrically at 298.15 K and I = 1.0(NaClO4). The heat effects of formation of the VO2CH2(COO) 2 − complex and step protonation of the malonate ion were determined for the first time. The data obtained were used to calculate the thermodynamic characteristics (logK, ΔG, ΔH, and ΔS) of the equilibria studied.

Reduction of AgI complexes with malonate ions in aqueous solution studied by pulse radiolysis

The formation of clusters CH2(COO−)(COOAg3 +) (absorption bands at 280 and 460 nm) by the reduction of silver ions in the presence of malonate ions in an aqueous solution was studied by pulse radiolysis. The disappearance of the clusters affords colloidal silver. The mechanism of silver nucleation was discussed, and the rate constants of some reactions were determined.

Trimethoprim–hydrogen malonate (1/1)

In the title compound, 2,4-di­amino-5-(3,4,5-tri­methoxy­benzyl)­pyrimidinium hydrogen malonate, C14H19N4O3+·C3H3O4−, the trimethoprim mol­ecule is protonated at one of the pyrimidine N atoms. The carboxyl­ate group of the hydrogen malonate ion accepts a pair of N—H⋯O hydrogen bonds from an adjacent trimethoprim mol­ecule, which is similar to the carboxyl­ate–trimethoprim cation interaction present in the complex of di­hydro­folate reductase with trimethoprim. An O atom of the carboxyl group forms an intramolecular O—H⋯O hydrogen bond with the carboxyl­ate group, leading to a folded conformation for the hydrogen malonate ion. Each hydrogen malonate ion bridges two di­amino­pyrimidine cations, via N—H⋯O and C—H⋯N hydrogen bonds, leading to a supramolecular ribbon made up of alternating cations and anions. Two such inversion-related ribbons are cross-linked by (amino)N—H⋯O(methoxy) hydrogen bonds, (pyrimidine)C—H⋯O(methoxy) hydrogen bonds and π–π stacking involving the benzene planes.

Cation effect on energy transfer reactions from [Tb(2,6-pyridinedicarboxylate) 3] 3− to anionic chromium(III) and neodymium(III) complexes in aqueous solutions

Cation effects are studied on the excitation energy transfer reaction between anionic complexes, i.e., [Tb(dpa) 3] 3− (dpa=2,6-pyridinedicarboxylate) quenched by [Cr(ox) 3] 3− (ox=oxalate ion), [Cr(mal) 3] 3− (mal=malonate ion) and [Nd(dpa) 3] 3− in aqueous solutions in the presence of alkali metal ions added for adjustments of ionic strengths. In the quenching reaction of [Cr(ox) 3] 3−, magnitudes of quenching rate constants ( k q) and energy transfer rate constant in encounter complex ( k 1) are changed by the cations in the order of Li + < Na + < K + ≈ Rb + ≈ Cs +, that is quite contrary of the cation effect on energy transfer reaction between [Ru(N–N) 3] 2+ and [Cr(ox) 3] 3−, reported in the previous paper. On the other hand, the rate constants in quenching reactions by [Cr(mal) 3] 3− and [Nd(dpa) 3] 3− remain almost constant. This result indicates that more separated donor-acceptor pair is not sensitive to coexisting cations.

Crystal Structure of Double Np(V) Malonate with Co(NH3)63+in the Outer Sphere, [Co(NH3)6][NpO2L]2HL (L = OOCCH2COO)

The single crystal X-ray analysis of [Co(NH3)6][NpO2L]2HL (L = OOCCH2COO) was carried out [monoclinic system, a = 17.925(6), b = 7.736(4), c = 7.879(3) A, β = 103.65(3)°, space group C2/m]. The structure consists of infinite anionic chains [NpO2L]nn-, [Co(NH3)]63+ cations, and HL- anions. The Np(V) atoms have hexagonal-bipyramidal oxygen surrounding. The coordination capacity of malonate ions is 6; two oxygen atoms (one of each carboxylate group) are bridging atoms between two Np atoms, owing to which the CPs of Np atoms share common equatorial edges to form infinite chains.

Double Np(V) Malonates with Co(NH3)63+in the Outer Sphere

Light yellow crystalline products of the general formula Co(NH3)6(NpO2L)2A·xH2O, where A = Cl, NO3, or ClO4, are precipitated with Co(NH3)63+ ions from weakly acidic chloride, nitrate, and perchlorate solutions of Np(V), containing up to 0.3 M CH2(COO)22- (L2-). When only malonate ions are present in the solution, Np(V) precipitates in the form of Co(NH3)6(NpO2L)2HL·H2O. These compounds are virtually insoluble in water and have similar X-ray patterns. Unlike oxalate and phthalate solutions, complex neptunyl(V) ion NpO2L23- is not precipitated with Co(NH3)63+ ions from malonate media of the above composition.

Aqua(malonato-κ2O,O′)(pyridine-2-carboxamide-κ2N1,O)copper(II) monohydrate

The title compound, [Cu(mal)(pca)(H2O)]·H2O [mal is the malonate dianion, CH2(COO)22−, and pca is pyridine-2-carbox­amide, C6H6N2O), has a five-coordinated Cu atom in a distorted square-pyramidal environment, coordinated by two O atoms of the malonate ion, an O atom and an N atom of pca, and an O atom of water. An uncoordinated water mol­ecule stabilizes the complex by participation in a hydrogen-bonding system. The crystal structure is built from layers parallel to the (111) plane.

Passivation of the calcite surface with malonate ion

Samples of polycrystalline calcite were impregnated with solutions of malonic acid of three concentrations (5×10 −2, 5×10 −3, and 5×10 −4 M) and different pH values (6.00, 7.00, and 8.00). The impregnation was carried out at room temperature to evaluate the adsorption of malonate ion in the calcite surface to optimize the conditions for possible application on limestone and marble in cultural heritage materials. The affinity of the malonate ion was determined through the potentiometric measurement of the surface charge and the corresponding adsorbed amounts by titration, Raman spectroscopy, and small-angle X-ray scattering (SAXS). The results indicate effective adsorption of the malonate ion on the surface at a pH value close to the point of zero charge (pH pzc≈8.20) and changes in some surface morphological properties such as the pore shape and the pore size distribution. The presence of a malonate adsorptive layer on calcite generates an interface interaction potential that may influence the reaction and transport mechanisms within the medium.

Specific cation effect on quenching reactions of excited tris(α,α ′-diimine)ruthenium(II) and tris(2,2 ′-bipyridine)chromium(III) by tris(oxalato)- and tris(malnato)chromates(III) in aqueous solutions

Specific salt effects were studied on the quenching reaction of excited [Ru(N–N) 3] 2+ (N–N=2,2 ′-bipyridine (bpy), 1,10-phenanthrorine (phen)) and [Cr(bpy) 3] 3+ by [Cr(ox) 3] 3− (ox=oxalate ion) and [Cr(mal) 3] 3− (mal=malonate ion) in aqueous solutions as a function of alkali metal ions which were added for adjustment of ionic strength. The value of k q, quenching rate constants, and k 1, energy transfer rate constant in encounter complex, is changed by the cations as the order of Li + > Na + > K + ≈ Rb + ⩽ Cs +, although diffusion rate constants are not changed by the co-existing cations. Among the quenching reactions investigated in this work, a ratio of k 1 values in the aqueous solutions whose ionic strength was adjusted with LiCl and KCl, k 1 LiCl/ k 1 KCl, is larger for quenching systems of closely approached donor-acceptor pair than loosely bounded pair. These results indicate that co-existing alkali cation tunes the distance between donor and acceptor in encounter complex where energy transfer occurs.

Palladium‐Catalyzed α‐Arylation of Carbonyl Compounds and Nitriles

AbstractFor Abstract see ChemInform Abstract in Full Text.

Palladium-catalyzed alpha-arylation of carbonyl compounds and nitriles.

The palladium-catalyzed alpha-arylation of ketones has become a useful and general synthetic method. In this process, an enolate is generated from a ketone and base in the presence of an aryl halide, and a palladium catalyst couples this enolate with the aryl halide. With the advent of new catalysts composed of sterically hindered, electron-rich alkylphosphine and N-heterocyclic carbene ligands, this process now encompasses a broad range of enolates and related anions, including those derived from amides, esters, aldehydes, nitriles, malonates, cyanoesters, nitroalkanes, sulfones, and lactones. In the proposed mechanism for this reaction, the carbon-carbon bond of the product is formed by reductive elimination from an arylpalladium enolate intermediate. The structures and reactions of arylpalladium complexes of enolate, cyanoalkyl, and malonate ions have been studied to determine how the binding mode and electronic and steric parameters influence the rate and mechanism of reductive elimination.

Spectroscopy of Hydrothermal Reactions 22. The Effects of Cations on the Decarboxylation Kinetics of Trifluoroacetate, Cyanoacetate, Propiolate, and Malonate Ions

The effect of Group 1 counterions on the decarboxylation rate of four carboxylate ions (trifluoroacetate, propiolate, cyanoacetate, and malonate) was determined in water at 140-280 °C and 275 bar. The decarboxylation kinetics were determined in real time by using IR spectroscopy and a titanium cell flow-reactor with sapphire windows. The complexity of the reaction of CF 3 CO 2 - necessitated additional postreaction studies by 1 H and 1 9 F NMR spectroscopy and F - ion electrochemistry. Batch mode reactions in a titanium tube reactor were employed for the latter studies. The CF 3 H product of CF 3 CO 2 - decomposed, liberating F - ions. The cation effect for CF 3 CO 2 - is caused primarily by the reaction of F - with the Group 1 cations in the order Li + > Na + > K + ..., which changed the ionic strength. The rate of decarboxylation of cyanoacetate was unaffected by the cation, whereas the Li + ion slowed the rate of decarboxylation of propiolate, perhaps because of complexation with propiolate. These results were compared with the previously investigated malonate system. Where a cation effect was observed, the effect could be attributed to some form of ion pairing, but in each case the details of the interaction differ slightly.