Preparation and properties of Fe3+-amino acid complexes

Tucker, William F.; Asplund, Rita; Holt, Smith L.

doi:10.1016/0003-9861(75)90406-3

Cited by 31 publications

(6 citation statements)

References 11 publications

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“…A series of high-energy transitions, seen as shoulders in the range 355 to 330 Similar bands have been observed in other related complexes (61,118,265,201,204,205). Circular dichroism measurements on a series of Lamino acid-bridged complexes are consistent with these assignments, and with the assignment of the intense absorptions in the region 200 to 425 nm as ligand-metal charge transfer, essentially localized on the Iigands (206).…”

Section: A Complexes Of the First-row Transition Metalssupporting

confidence: 71%

“…A considerable number of related complexes have been characterized, chemically and/or crystallographically, in a series of papers by Asplund, Puri, Holt, and co-workers (61,117,118,200,205,245,246,265). They include complexes of peptides such as triglycine, but still with only the carbovyl group coordinated and bridging the metal atoms in the usual way.…”

Section: Solid Iroti(i1l) Complexesmentioning

confidence: 99%

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Chemical and Physical Properties of Triangular Bridged Metal Complexes

Cannon¹,

White²

1988

Progress in Inorganic Chemistry

411

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Section: A Complexes Of the First-row Transition Metalssupporting

confidence: 71%

Section: Solid Iroti(i1l) Complexesmentioning

confidence: 99%

Chemical and Physical Properties of Triangular Bridged Metal Complexes

Cannon¹,

White²

1988

Progress in Inorganic Chemistry

411

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“…Preliminary investigations in our laboratory suggest that all these are equally effective as intercalants. Secondly, the carboxylate groups can be replaced by amino acid groups to form analogous glycine and alanine complexes (Holt et al, 1974;Tucker et al, 1975 ;Thundathil et al, 1977). The reaction of these complexes with clays is so far unknown.…”

Section: Discussionmentioning

confidence: 99%

Preparation and characterization of iron oxide pillared montmorillonite

et al. 1988

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A B S T RA C T : Pillared smectites in which the pillars consist of iron oxide are expected to have interesting and unusual magnetic properties. Several possible routes by which such materials might be made have been investigated, namely intercalation of hydroxy-Fe(III) polycations, mixed hydroxy-Fe(III)/Al polycations, phenanthroline-Fe(II) cations, and trinuclear Fe(III) acetato cations into Na-montmorillonite. Only the last of these yielded a pillared clay (PILC) on calcination. The products have been characterized using X-ray powder diffraction and 57Fe M6ssbauer spectroscopy. The precursor Fe-PILC has a d-spacing of 21 A and expands to 23 A on solvation with glycol. The calcined Fe-PILC has a d-spacing of 19 A (gallery height 9.4 A) and does not expand with glycol, confirming cross-linking of the layers. From M6ssbauer spectra at 4.2 K it is estimated that there are of the order of some hundred Fe atoms per pillar.Pillared or cross-linked smectites, in which the interlayer is converted into a two dimensional zeolite-like structure, have recently attracted much interest because of their catalytic and molecular sieving properties (Pinnavaia, 1983;Barrer, 1986). The best understood pillared clays (PILCs) are those in which Al oxide pillars act as molecular-sized props permanently separating the silicate layers of the clay, and the structure of these materials has been investigated using 27A1 and 29Si solid state MAS NMR (Tennakoon et al., 1986;Plee et al., 1985Plee et al., , 1987. If, however, the pillars are formed of Fe oxide instead of A1 oxide, interesting and novel magnetic properties may be expected (Gangas et al., 1985) and M6ssbauer spectroscopy can be utilized to obtain structural information.Metal oxide pillared clays are normally the product of a two step process. The first step is one of cation exchange in which the simple interlayer cation of a smectite (usually Na +) is replaced by a large complex cation. The second step consists of a heat treatment which crosslinks the silicate layers. In this paper, the terms precursor-PILC and calcined-PILC are used in order to make a clear distinction between the products obtained after each step.The complex cation which is used in the preparation of A1-PILCs is the Keggin-like ion [AllaO4(OH)24(H20)12] 7+ (Baes & Mesmer, 1976). In this study we have investigated the PILC-forming potential of a number of large Fe cations which can occupy the exchange sites in smectite interlayers. These are hydroxy-Fe(III) polycations, mixed hydroxy-Fe(III)/Al cations, phenanthroline-Fe(II) complexes and trinuclear Fe(III) carboxylate complexes. CHARACTERISTICS OF METAL OXIDE PILLARED CLAYSIntercalation of complex cations into a smectite followed by heat treatment may, or may not, result in the formation of a PILC. The following three criteria have been used to identify 9 1988 The Mineralogical Society

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“…91,92 Unlike results observed after Fe 2+ addition, results with copper suggest that the catecholamines do not readily oxidize Cu + to Cu 2+ , possibly due to the low affinity of Cu + for catechol binding. 60,68 Although glycine and other amino acids form stable complexes with iron and copper, [93][94][95][96][97][98] UV-vis spectra for the amino acid neurotransmitters Gly, Glu, and GABA show no significant absorbance changes upon Fe 2+ addition (Fig. S22 †), so iron oxidation cannot be determined using this method.…”

Section: Iron and Copper Binding To Neurotransmittersmentioning

confidence: 99%

Prevention of iron- and copper-mediated DNA damage by catecholamine and amino acid neurotransmitters, l-DOPA, and curcumin: metal binding as a general antioxidant mechanism

et al. 2012

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Concentrations of labile iron and copper are elevated in patients with neurological disorders, causing interest in metal-neurotransmitter interactions. Catecholamine (dopamine, epinephrine, and norepinephrine) and amino acid (glycine, glutamate, and 4-aminobutyrate) neurotransmitters are antioxidants also known to bind metal ions. To investigate the role of metal binding as an antioxidant mechanism for these neurotransmitters, L-dihydroxyphenylalanine (L-DOPA), and curcumin, their abilities to prevent iron- and copper-mediated DNA damage were quantified, cyclic voltammetry was used to determine the relationship between their redox potentials and DNA damage prevention, and UV-vis studies were conducted to determine iron and copper binding as well as iron oxidation rates. In contrast to amino acid neurotransmitters, catecholamine neurotransmitters, L-DOPA, and curcumin prevent significant iron-mediated DNA damage (IC(50) values of 3.2 to 18 μM) and are electrochemically active. However, glycine and glutamate are more effective at preventing copper-mediated DNA damage (IC(50) values of 35 and 12.9 μM, respectively) than L-DOPA, the only catecholamine to prevent this damage (IC(50) = 73 μM). This metal-mediated DNA damage prevention is directly related to the metal-binding behaviour of these compounds. When bound to iron or copper, the catecholamines, amino acids, and curcumin significantly shift iron oxidation potentials and stabilize Fe(3+) over Fe(2+) and Cu(2+) over Cu(+), a factor that may prevent metal redox cycling in vivo. These results highlight the disparate antioxidant activities of neurotransmitters, drugs, and supplements and highlight the importance of considering metal binding when identifying antioxidants to treat and prevent neurodegenerative disorders.

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Preparation and properties of Fe3+-amino acid complexes

Cited by 31 publications

References 11 publications

Chemical and Physical Properties of Triangular Bridged Metal Complexes

Chemical and Physical Properties of Triangular Bridged Metal Complexes

Preparation and characterization of iron oxide pillared montmorillonite

Prevention of iron- and copper-mediated DNA damage by catecholamine and amino acid neurotransmitters, l-DOPA, and curcumin: metal binding as a general antioxidant mechanism

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