Acetic Acid Complex Research Articles

Crystal Structure and Thermal Analysis of Erbium Complex with Benzene Acetic Acid

The crystal structure of erbium (III) complex of benzene acetic acid is reported. The complex crystallizes in the monoclinic space group P2(1)/a with a = 0,9008(3)nm, b=1.4242(5) nm, c=1.8437(7) nm, beta=98.80(3)degrees, V = 2.337(1) nm(3), Z = 4. The mechanism of thermal decomposition of complex has been studied by TG-DTG-DTA. The activation energy for dehydration reaction has been calculated by Freeman Carroll method. The enthalpy change for dehydration and phase change process has been determined.

Ring-methyl activation in pentamethylcyclopentadienyliridium complexes. Part 2. Synthesis of C5Me4(functionalized alkyl) complexes and crystal structures of [(C5Me4CH2CPh2OH)-IrMe(CO)Ph] and [(C5Me4CH2CO2H)IrMe(CO)Cl

Reaction of [(C5Me5)IrMe(CO)Ph]1 with sec-butyllithium gives a lithio complex, presumably Li[(C5Me4CH2)IrMe(CO)Ph]2, which reacts with PhCOR to give the appropriately substituted [{C5Me4CH2CPh(OH)R}IrMe(CO)Ph]3a(R = Me) and 3b(R = Ph). Hydrogen chloride cleaved the Ir–Ph bonds in complexes 3a and 3b to give first [{C5Me4CH2CPh(OH)R}IrMe(CO)Cl]4, which reacted further with HCl to give [{C5Me4CH2CPh(Me)Cl}Ir(CO)Cl2]5, from 4a, and [(C5Me4CHCPh2)Ir(CO)Cl2]6, from 4b. Complex 2 also reacted with PhCN and with CO2 to give, after work-up, the substituted acetophenone and the substituted acetic acid complexes [(C5Me4CH2COPh)IrMe(CO)Ph]7 and [(C5Me4CH2CO2H)IrMe(CO)Cl]8, respectively. Complex 8 was converted by further HCl into [(C5Me4CH2CO2H)Ir(CO)Cl2]9, or esterified (ROH, base and dicyclohexylcarbodiimide) to give [(C5Me4CH2CO2R)IrMe(CO)Cl]10a(R = Me) or 10b(R = 1R,2S,5R-menthyl). Complex 9 was also esterified (EtOH, HCl) to give [(C5Me4CH2CO2Et)Ir(CO)Cl2]11. Reaction of the complex [{C5Me4(CH2SiMe3)}IrMe(CO)Ph]12 with sec-butyllithium followed by CO2 gave [{C5Me3(CH2-CO2H)(CH2SiMe3)}IrMe(CO)Cl]13. X-Ray structure determinations of complexes 3b and 8 were carried out: 3b shows no hydrogen bonding, but molecules of 8 are linked across a crystallographic inversion centre by pairs of strong hydrogen bonds between the carboxylic acid residues.

Absorption and Fluorescence Spectra of 1-Methyl-2(1H)-pyridinimines and 2-Methylaminopyridine–Acetic Acid Complex

Abstract Upon the addition of acetic acid to 2-methylaminopyridine in isooctane, weak absorption and fluorescence bands appeared near 350 and 465 nm at the tail of the main bands, respectively. These new bands were attributed, on the basis of the spectral results of 1-methyl-, 1,3-dimethyl-, 1,4-dimethyl-, 1,5-dimethyl-, and 1,6-dimethyl-2(1H)-pyridinimines, and 1-methyl-2-methylimino-1,2-dihydropyridine, to have originated from 2(1H)-pyridinimine moiety (iminoform tautomer) in the 2-methylaminopyridine-acetic acid complex. In addition, the fluorescence quantum yields of the 1-methyl-2(1H)-pyridinimines in isooctane were shown to be very small.

NMR and indo study of Ni(II) complexes of acetic and propionic acid

The combined use of NMR spin-lattice relaxation and contact shift to investigate the conformational and dynamical properties of Nickel acetate and propionate complexes is reported. The analysis of the C-13 and H-1 contact shift together with INDO MO calculations gave information on the delocalization mechanism and geometries of the complexes. From these geometries, and by means of C-13 and H-1 spin lattice relaxation spectroscopy the correlation time for Ni-ligand dipolar interaction was calculated and found to be identical to the Ni 2+ electron spin lattice relaxation time.

Influence of Structure Breaking and Structure Forming Ions on the Dissociation Mechanism of Acetic Acid in Aqueous Solutions

Using a rotating disc electrode, the dissociation rate of acetic acid in various aqueous electrolyte solutions is studied. Li+ , Cs+ and (CH3)4N+ at 1 M concentration considerably modify the activation enthalpy and entropy of the reaction. Evidently the interaction between the cations and water influences the dissociation mechanism of the weak acid. In the presence of 1 molar Li+ the activated complex of acetic acid seems to contain only one water molecule instead of two in the other cases.

Radioimmunoassay of 5-Hydroxy-3-indole Acetic Acid

A direct radioimmunoassay of the methyl ester of urinary and serum 5-hydroxy-3-indole acetic acid is described. The antiserum, raised in a rabbit against a conjugate of bovine serum albumin with 5-hydroxytryptamine hemisuccinamide, contained two antigenic fractions, one binding N-acyl 5-hydroxytryptamine, and the other binding methyl ester of 5-hydroxy-3-indole acetic acid, and N-acyl 5-hydroxytryptamine. The N-acyl 5-hydroxytryptamine binding fraction was removed by affinity chromatography on a N-acyl 5-hydroxytryptamine agarose gel in the presence of excess methyl ester of 5-hydroxy-3-indole acetic acid. The antibody methyl ester of 5-hydroxy-3-indole acetic acid complexes were dissociated and this affinity-purified antiserum was used in all experiments. Polyethylene glycol in combination with goat anti-rabbit IgG was used to separate bound and unbound 125I-labeled Bolton-Hunter reagent- 5-hydroxytryptamine conjugate. Sample preparation (esterification of 5-hydroxy-3-indole acetic acid to its methyl ester) was performed with trimethylsilyldiazomethane in dioxane. In the analysis of urine, the reagents used in the methylation served as diluents, contributing to the final dilution of 1:1100. In the analysis of serum, a deproteination step (ethanol precipitation) prior to methylation was necessary to obtain reproducible results. The methylated 5-hydroxy-3-indole acetic acid was then extracted with ethyl acetate and the extract redissolved in assay buffer. The minimal detectable concentration of methyl ester of 5-hydroxy-3-indole acetic acid was 1.1 mumol/l (0.21 mg/l 5-hydroxy-3-indole acetic acid) urine or 100 fmol/tube.(ABSTRACT TRUNCATED AT 250 WORDS)

Proton-transfer spectroscopy. Perturbation of the tautomerization potential

The phenomena of excited-state intramolecular proton transfer (phototautomerization) are distinguished in molecular mechanism according to four classes. Intrinsic intramolecular proton transfer (e.g. 3-hydroxyflavone) involves ultra-rapid proton transfer across an internal H-bond. Concerted biprotonic transfer (e.g. 7-azaindole dimers and solvates, benzanilide dimers) involves cooperative double proton transfer in a cyclical complex. Static and dynamic catalysis of proton transfer (e.g. lumichrome, adenine, guanine) involves strong catalysis in doubly H-bonded acetic acid complexes, or a proton transport by H-bonded pyridine. Proton-relay transfer (e.g. 7-hydroxyquinoline, 3-hydroxyxanthone) is suggested as involving multiproton-bridged solvates, which may serve as experimental models for proton relays and proton pumps in biological systems.

Rhodium(I) carbonyl complexes of (diphenylphosphino)acetic acid

Preparation des complexes Rh(CO)X(HA) 2 et Rh(CO)A(HA) avec HA=acide du titre. Etude RX de α-Rh(CO)A(HA)

Metal—(phenylthio)acetic acid interactions. Part 3. The crystal structures of anhydrous barium (phenylthio)acetate and the potassium (phenylthio)acetate-(phenylthio)acetic acid adduct

The crystal structures of barium and potassium complexes of (phenylthio)acetic acid (PTAH) have been determined using X-ray diffraction. The barium analogue, [Ba(PTA) 2] n(1) is monoclinic, space group C2 with Z = 2, a = 7.219(4), b = 5.894(2), c = 19.272(2) Å, β = 91.57(4)°. [K(PTA)(PTAH)] n(2) is triclinic, space group P 1 with Z = 2, a = 6.272(1), b = 7.222(1), c = 18.459(3) Å, α = 97.23(1), β = 93.64(1), γ = 97.31(1)°. The structures of (1) and (2) were refined to residuals of 0.047 and 0.053 for 844 and 2628 ‘observed’ reflections respectively. The MO 8 coordination about Ba in (1) is distorted ‘cubic’ with four oxygens from two bidentate carboxylate groups [BaO, 2.86, 2.97(3) Å] and four oxygens from adjacent carboxylates [BaO, 2.68, 2.69(2) Å] forming an infinite 2-dimensional polymer structure. (2) is polymeric and has bonded PTA as well as adducted PTAH species. There are seven KO contacts ranging from 2.729–3.034(3) Å from both PTA and PTAH species in an irregular coordination.

Structure and van der Waals energy study of the palmitic acid–choleic acid complex

The crystals are orthorhombic, space group P2,2121, a = 26.020 (4), b = 13.543 (2), c = 7.268 (1) ,~, and the structure has been refined to an R of 0.11 and R w of 0.16 for 2352 observed data with I > a(I). The packing is characterized by an assembly of bilayers similar to that of other orthorhombic phases. The shape of the canals, in which the palmitic acid is accommodated, differs slightly from that in the acetic acid-choleic acid complex. The guest molecules, which are probably arranged in four statistical orientations, run along c in a trans-planar conformation and occupy approximately three unit cells. Potential-energy calculations allowed the location of the occluded molecules and suggest a deoxycholic acid:palmitic acid: ethanol ratio of 8 : 1 : 1.

Molecular orbital study of hydrogen bonding and proton transfer in the system acetic acid - pyridine: isolated system and solvent effect

The intermolecular hydrogen bond and proton transfer of the system, acetic acid - pyridine was investigated by means of the semi-empirical PCILO (Perturbative Configuration Interaction using Localised Orbitals) method. A potential curve with a single minimum was found in the 1:1 complex of acetic acid - pyridine. The effect of specific solvation (within the so-called supermolecule approach) on the potential curves for proton transfer was studied in the systems, acetic acid - pyridine × nH20 (n=2,3). The PCILO calculations, in agreement with experiments, have shown that these systems also form simple hydrogen bonded complexes.

Infrared studies of complexes between carboxylic acids and tertiary amines in argon matrices

The infrared spectra of the complexes formed between acetic and trifluoroacetic acids and tertiary amines [N(CH3)3, N(C2H5)3] in argon matrices and for two-component solid mixtures of acid and amine have been recorded. The spectra show that both 1 : 1 and 2 : 1 complexes of acetic acid and amine isolated in argon matrices have molecular forms characterized by broad vOH absorption at ≈ 2000 cm–1. In an acidic environment in both highly concentrated argon matrices and in two-component solid mixtures the proton transfer form CH3CO–2⋯H+NR3 was identified. The 2 : 1 complexes of trifluoroacetic acid and amine isolated in argon matrices have an ionic form as identified by the appearance of characteristic carboxylate group absorption. The spectra also suggest that the 1 : 1 complex forms an ion pair in an argon matrix but this is not conclusive.

Acetic acid complex of 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (trp-P-1); a potent mutagenic product from the dry distillation of tryptophan

Acetic acid complex of 3-amino-1,4-dimethyl-5<i>H</i>-pyrido[4,3-<i>b</i>]indole (trp-P-1); a potent mutagenic product from the dry distillation of tryptophan

Infrared spectroscopic determination of the liquid-vapor equilibrium in the ternary system hexamethyldisiloxane-chloroform-carbon disulfide

indicates an advantage for higher molecular weight amines. Along this line, the water-soluble base in TOPO solvent mixtures, noted in Experimental Procedure, should be explored and identified as TOPO itself, an impurity in the TOPO and/or a complex of TOPO and acetic acid. Formic Acid ws. Acetic Acid. Tables I X and X compare the extractions of formic acid and acetic acid with various phosphoryl and amine solvents. In all cases the formic acid is more effectively extracted. The results for the amines agree with other authors (5, 6) , who have found that these solvents extract stronger acids more effectively.

A receptor protein for indoleacetic acid from plant chromatin and its role in transcription

A high affinity, low capacity binding protein for the plant hormone indole acetic acid has been isolated from the non-histone chromosomal proteins of coconut ( Coccos nucifera ) endosperm cells. The protein appears to be homogeneous in native and denaturing conditions in polyacrylamide gel electrophoresis and has a molecular weight 70,000 dalton. A role as an acceptor site has been shown for this protein in the transcription of chromatin in presence of nucleoplasmic receptor and indole acetic acid complex. A maximum stimulation in the synthesis of 9 – 12S RNA has been recorded.

Proton chemical shifts of hydrogen bonded complexes of acetic acid. Electric field calculations for the monomer–dimer shift and for complexes with fluoride or acetate anions

The permanent electric moments and the mutual polarisation of two acetic acid molecules in the dimer configuration are sufficient to account for the gas phase 1H association shift of the hydroxyl proton. A cyclic trimer configuration has a larger association shift than a dimer and such a component may account for the measured chemical shift of liquid acetic acid being low field of the probable dimer shift. The calculated shift of the hydroxyl proton hydrogen bonded to fluoride or acetate anions is much larger than the measured shift and this is rationalised in terms of the interaction of the anions with pairs of associated molecules and not simply with monomer acid.

New catalyst system for easy‐care cotton finishing

AbstractA new catalyst system, based on a mixture of boron trifluoride–acetic acid complex (BF3·2CH3COOH) and magnesium chloride hexahydrate (MgCl2·6H2O), has been examined in cotton finishing treatment for producing easy‐care properties. It provides strong catalysis in crosslinking cotton with a series of N‐methylol finishing agents when the pad‐dry‐cure process is applied. Curing can be carried out at a temperature of 130–150°C for a period of 1–3 min, dependent on the temperature used. The resilience and abrasion resistance properties as well as the degree of polymerization (D.P.) of the crosslinked cotton so obtained were equivalent or slightly better than those of crosslinked cottons catalyzed by conventional catalysts. The influence of the new catalyst as well as a number of conventional catalysts, viz., ammonium chloride, ammonium dihydrogen phosphate, magnesium chloride hexahydrate, and zinc nitrate hexahydrate, on some properties of cotton fabrics was also investigated. The behavior of these catalysts in the presence of the N‐methylol finishing agent was quite different from their behavior in its absence. With the exception of ammonium salts, the D.P. of crosslinked cotton was much higher than that of cotton treated with the catalyst only. The opposite holds true for the abrasion resistance.

Preparation and Properties of Cobalt(II) and -(III) Complexes of (2-Aminoethylthio)acetic Acid

Abstract The cobalt(II) and -(III) complexes of (2-aminoethylthio) acetic acid (HL), [CoL2]·H2O, trans-(N)-[CoL2]Cl and cis(N)-[CoL2]Cl·2H2O were prepared and characterized. These complexes are octahedral in which the ligand is coordinated through the N, S and O atoms as a terdentate ligand.

Studies on iron(III) and copper(II) complexes of bromo dehydro acetic acid (BrDAA)

Studies on iron(III) and copper(II) complexes of bromo dehydro acetic acid (BrDAA)

The linkage isomerism in palladium(II) complexes of acetic acid

The linkage isomerism in palladium(II) complexes of acetic acid