Metal Complexes of the Amino Acid DL-Methionine

McAuliffe, Charles A.; Quagliano, J. V.; Vallarino, L. M.

doi:10.1021/ic50045a034

Cited by 149 publications

(53 citation statements)

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“…Figure 1 shows the visible spectra of various mixtures like Cu(II)SO 4 , Cu(II)/Histidine, Cu(II)/ Histidine/MMA, Cu(II)/Histidine/MMA/KMPS,Cu(II)/ Histidine/MMA/KPS, and Cu(II)/Histidine/MMA/APS measured to obtain complete picture of the interaction between the reacting components and their relationship with the rate data. The tridentate ligand character of amino acids in conjunction with colored cations like Cu(II) to form a complex in an acidic medium (pH = 2.7) is well recognized [17][18][19] and in case of copperhistidyl complexes in aqueous solution, the involvement of imidazole nucleus in coordination with copper along with their stability constants has been reported 20,21 as per the structure in Scheme 1. The ML type structure of the complex was established from the proportionalities obtained from the rate equation, i.e., Cu(II): Histidine as 1:1 with stability constant log k 10.25.…”

Section: Resultsmentioning

confidence: 99%

Nonconventional Emulsion Polymerization of Methyl Methacrylate. Effect of Cu(II)/Histidine Complex Catalyst and Different Peroxo-Salts

Sahoo

Sahu

Swain

2003

Polym J

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ABSTRACT:The characteristics of nonconventional (soap-free) aqueous emulsion polymerization reactions of methyl methacrylate were evaluated by the catalytic effect of in situ developed different transition metal (II) chelate complex with amino acids initiated by different peroxo salts like potassium monopersulfate (KMPS, KHSO 5 ), potassium persulfate (KPS, K 2 S 2 O 8 ), ammonium persulfate (APS, (NH 4 ) 2 S 2 O 8 ). From the comparative data, the CuSO 4 /histidine chelate complex was selected as a novel catalyst for a detailed kinetic and spectrometric study of polymerization. Both kinetic and thermodynamic aspects of the polymerization dictate which initiator and particle morphology are obtained. The complex catalyzed polymerization proceeded smoothly until high conversion and yielded stable emulsions. The apparent activation energies (E a ) for the complex catalyzed emulsion polymerization were computed for different initiators to be 34, 38, and 46 kJ mol −1 , each a very low value. Use of these values and activation energies of propagation and termination for MMA gave an unexpectedly low activation energies (E d , 26, 34, and 51 kJ mol −1 for KMPS, KPS, and APS respectively) to the decomposition of different persulfate initiators in the complex catalyzed system. The emulsion polymer latex was characterized through the determination of average molecular weights of the purified polymers by gel permeation chromtography (GPC) and viscosity methods and the morphology by scanning electron microscopy (SEM).The coordination complex catalytic system shows excellent industrial performance characteristics in preparing micro-to nano-scale latex particles. KEY WORDS Complex Catalysis / Soap-Free Emulsion / Kinetics / Micro-Particles / Scanning Electron Microscopy (SEM) /In recent years number of papers have been published on emulsion polymerization of vinyl monomers using persulfates as initiators. 1-5 Also several studies were done in the emulsion polymerization of vinyl monomers using different redox pair initiation systems. [6][7][8][9][10][11][12][13] However the use of these initiation systems were not straight forward and often leads to low conversion of monomers to polymer in oxygen-free (inert) atmosphere. Again most of these processes were carried out at high temperatures, but none of these functioned suitably for commercial purpose.In our different publications we have reported the emulsifier-free emulsion polymerization of acrylonitrile initiated by potassium monopersulfate together with in situ developed complex initiating systems, such as Cu(II)/Glycine 14 and Cu(II)/H 2 Salen 15 with comparison of results of N 2 atmosphere with that of the O 2 atmosphere in order to design a simple low-cost polymerization technique.The present work attempts the study on the soapfree emulsion polymerization of MMA with novel catalytic action of in situ developed complex of Cu(II) salts with a series of water soluble amino acids initiated by three peroxo salts and describes the kinetic results and the morphology of particles...

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Section: Resultsmentioning

confidence: 99%

Nonconventional Emulsion Polymerization of Methyl Methacrylate. Effect of Cu(II)/Histidine Complex Catalyst and Different Peroxo-Salts

Sahoo

Sahu

Swain

2003

Polym J

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“…Molar extinction coefficients (ξ) for Co(II) and Ni(II) complexes are also presented in 3 cm -1 and 923 cm -1 , respectively, being similar to those obtained for the octahedral Ni(II) complexes of the amino acids methionine, methionine sulfoxide and S,S'-methylenebis(cysteine), ligands which are structurally related to deoxyalliin. [8][9][10] It is important to stand out that for the Co(II) and Ni(II) complexes, the electronic absorption spectra in aqueous solution were obtained immediately after the ligand and the metal salt were mixed, in order to avoid precipitation of the complex.…”

Section: Electronic Absorption Spectroscopymentioning

confidence: 99%

Four new metal complexes with the amino acid deoxyalliin

Massabni¹,

Corbi²,

Melnikov³

et al. 2005

J. Braz. Chem. Soc.

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] were obtained from the reaction of cobalt(II), nickel(II), copper(II) and iron(II) salts with the potassium salt of the amino acid deoxyalliin (S-allyl-L-cysteine). Electronic absorption spectra of the complexes are typical of octahedral structures. Infrared spectroscopy confirms the ligand coordination to the metal ions through (COO -) and (NH 2 ) groups. EPR spectrum of the Cu(II) complex indicates a slight distortion of its octahedral symmetry. Mössbauer parameters permitted to identify the presence of iron(II) and iron(III) species in the same sample, both of octahedral geometry. Thermal decomposition of the complexes lead to the formation of CoO, NiO, CuO and Fe 2 O 3 as final products. The compounds show poor solubility in water and in the common organic solvents.

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“…may give us a clue to understand the role of chromium(III) in biological processes as well as to get rid of toxic chromium(VI) from the body. Chromium(III) forms complexes with amino acids as ligand 7,8 . Khade et.al., 9 has reported the preparation and stability of chromium complexes with drug salbutamol and amino acids.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Sucrose Complexes of Chromium and the Study of their Viability as Food Supplement for Chromium Deficiency

2014

Chem Sci Trans

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Chromium(III) is biologically active ingredient of food and is known to enhance the action of insulin, a hormone critical to metabolism and storage of carbohydrate, fat and protein in body. On the other hand, chromium(VI) is toxic substance in any form. Chromium deficiency may be cured by commercially available food supplements like chromium picolinate and chromium polynicotinate. In the present work, we report the method of preparation and characterization of products formed by the interaction of di-tertiary butyl chromate with sucrose in order to explore whether the products containing chromium(III) in combination with oxidised products of sucrose can be used as food supplement for chromium deficiency.

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Metal Complexes of the Amino Acid DL-Methionine

Cited by 149 publications

References 0 publications

Nonconventional Emulsion Polymerization of Methyl Methacrylate. Effect of Cu(II)/Histidine Complex Catalyst and Different Peroxo-Salts

Nonconventional Emulsion Polymerization of Methyl Methacrylate. Effect of Cu(II)/Histidine Complex Catalyst and Different Peroxo-Salts

Four new metal complexes with the amino acid deoxyalliin

Preparation of Sucrose Complexes of Chromium and the Study of their Viability as Food Supplement for Chromium Deficiency

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