Design of metal chelates with biological activity. 3. Nickel(II) complexes of alkyl and amino hydroxamic acids

Spectrophotometric investigations of highly fluorescent metal chelating molecules are of relevance due to their potential application in novel, selective fluorescence-based sensors. Benzene and naphthalene chromophores are highly fluorescent while hydroxamic acids are widely used as ligands for complexation of transition metals. In order to develop fluorescence probes, several phenyl derivatives of N-phenylbenzohydroxamic acid and an aminodihydroxamic acid linked with a naphthalene chromophore were synthesized and their selective ionophoric properties towards iron(III) and manganese(II) ions were investigated using fluorescence and absorption spectroscopy. Both methods confirm the formation of 1:1 and 1:2 complexes for iron(III) and a 1:1 complex for manganese(II). The complex that is formed depends on the concentration of the ligand and pH of the medium. The amino dihydroxamic acid exhibits a prominent selectivity towards iron(III) with a two-step 1:1 and 1:2 quenching mechanism at pH 3 and towards manganese(II) with a 1:1 quenching mechanism at a probe concentration of 1 x 10(-5) mol dm(-3) at pH 9.5 The logarithm of overall formation constants of 1:1 and 1:2 complexes of iron(III) were estimated as 3.30 and 9.05, respectively.

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“…8). This argument agrees with the complexation behaviour of aminohydroxamic acids reported in some previous studies (13).…”

Section: Resultssupporting

confidence: 93%

Fluorescence quenching and bonding properties of some hydroxamic acid derivatives by iron(III) and manganese(II)

2008

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“…[64,65] Figure 9. Two distinct bidentate binding modes observed in some complexes of α-aminohydroxamic acids In the case of nickel(), α-aminohydroxamate ligands produce bis N,N-bidentate square-planar complexes [59,66] rather than octahedral complexes containing O,O-bonded hydroxamates. With these ligands, the cobalt() complex forms tris complexes that have N,N-bidentate coordination.…”

Section: Hydroxamate Ligands With Other Coordinating Groups; Metallacmentioning

confidence: 99%

Hydroxamic Acids − An Intriguing Family of Enzyme Inhibitors and Biomedical Ligands

2004

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“…5Ϫ6) indicates that this proton is being pushed by the metal ion. A rough evaluation of the stability constant of the neutral species (log β CuL ഠ 19) indicates that it would be quite high and closer to the corresponding overall constants of the 1:2 complex (log β CuL2 ) for α-aminohydroxamic acids (19.89 for glycinehydroxamic acid) [21] than for simple hydroxamic acids (14.06 for acetohydroxamic acid). [22] …”

Section: Copper(ii) Complexationmentioning

confidence: 90%

A New Diazacyclooctane Dihydroxamate as a Siderophore Analogue − Synthesis and Equilibrium Studies of Iron(III) and Copper(II) Complexes

Gaspar

Telo²,

Santos³

2003

Eur J Inorg Chem

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A new siderophore analogue based on the mesocyclic diamine 1,5‐diazacyclooctane (DACO) functionalized with two additional hydroxamate donor pendant groups, 1,5‐diazacyclooctane‐1,5‐bis(N‐methylacetohydroxamic acid) (DACODMAHA), has been synthesized from the corresponding diacetate derivative (DACODA). The complexation behaviour of this ligand towards CuII and FeIII in aqueous solution has been studied by potentiometry, UV/Vis and EPR spectroscopy and magnetic moment measurements. The CuII complexation involves the formation of a mononuclear species with a tetradentate mixed amine/hydroxamate coordination mode, whereas the FeIII complexation involves a binuclear species with Fe2L3 stoichiometry and normal {O,O}‐hydroxamate coordination mode. The redox potential of the iron complexes and the corresponding electron transfer mechanism are also evaluated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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Design of metal chelates with biological activity. 3. Nickel(II) complexes of alkyl and amino hydroxamic acids

Cited by 46 publications

References 0 publications

Fluorescence quenching and bonding properties of some hydroxamic acid derivatives by iron(III) and manganese(II)

Fluorescence quenching and bonding properties of some hydroxamic acid derivatives by iron(III) and manganese(II)

Hydroxamic Acids − An Intriguing Family of Enzyme Inhibitors and Biomedical Ligands

A New Diazacyclooctane Dihydroxamate as a Siderophore Analogue − Synthesis and Equilibrium Studies of Iron(III) and Copper(II) Complexes

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