An EPR and voltammetric study of simple and mixed copper(II) complexes with L- or D-glutamate and L-arginate in aqueous solution(128 visite)(PDF privato98 visite) Valora G, Bonomo RP, Tabbì G
Parole chiave: Cw Epr, Cu(ii) Complexes, Aminoacidate Ligands, Trans Copper Conformers, Electrostatic Interactions, Swv Formal Redox Potentials,
Affiliazioni:
*** IBB - CNR *** Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Viale A. Doria 6, 95125 Catania, Italy CNR, Istituto di Biostrutture e Bioimmagini, Via P. Gaifami 18, 95126 Catania, Italy
[14] R. Bregier-Jarzebowska, J. Solution Chem. 43 (2014) 2144–2162.
[15] G. Brookes, L.D. Pettit, J. Chem. Soc., Dalton Trans. (1977) 1918–1924.
[16] T. Lund, J. Vanngard, Chem. Phys. 42 (1965) 2979–2980.
[17] T. Sakurai, O. Yamauchi, A. Nakahara, Bull. Chem. Soc. Japan 51 (1978) 3203–
[18] E. Kaifer, J. Bard, J. Phys. Chem. 89 (1985) 4876–4880.
[19] N. Ohata, H. Masuda, O. Yamauchi, Inorg. Chim. Acta 302 (2000) 749–761.
[20] L. Borer, D. Gallagher, J. Ready, ChemBio News 15 (1) (2005) 40.
[21] M.S. Bukharov, V.G. Shtyrlin, A.S. Mukhtarov, G.V. Mamin, S. Stapf, C. Mattea, A. A. Krutikov, A.N. Il’in, N.Y. Serov, Chem. Phys. 16 (2014) 9411–9421.
[22] R.P. Bonomo, F. Riggi, A.J. Di Bilio, Inorg. Chem. 27 (1988) 2510–2512.
[23] R.P. Bonomo, F. Riggi, Chem. Phys. Lett. 93 (1982) 99–102.
[25] J.E. Wertz, J.R. Bolton, Electron Spin Resonance. Elementary Theory and Practical Applications, Mac Graw Hill, New York, 1972.
[26] B.A. Goodman, D.B. McPhail, H. Kipton, J. Powell, J. Chem. Soc., Dalton Trans.
[27] H.A. Kuska, M.T. Rogers, Electron Spin Resonance of Transition Metal Complex Ions, Coordination Chemistry, in: A.E. Martell (Ed.), ACS Monograph, vol. 1, Van Nostrand Reinhold Company, New York, 1971.
[28] H. Masuda, A. Odani, T. Yamazaki, T. Yajima, O. Yamauchi, Inorg. Chem. 32
[29] P. Pary, L.N. Bengoa, W.A. Egli, J. Electrochem. Soc. 162 (2015) D275–D282.
[30] G. Tabbì, A. Giuffrida, R.P. Bonomo, J. Inorg. Biochem. 128 (2013) 137–145.
[31] T. Weiser, M. Wienrich, Brain Res. 742 (1996) 211–218.
EPR CW measurements at room and low temperature have been carried out on the systems containing<br>63copper(II) nitrate, L-Arg and L-or D-Glu or DL- racemic mixtures of both amino acids in aqueous solution<br>or in mixed solvents. For these copper(II) bis and ternary complexes, RT EPR spectra revealed that mixtures<br>of cis and trans conformers are really present in aqueous solution. In most cases, for these systems,<br>the cis conformer is more abundant at the lowest temperature (275 K). Increasing gradually the temperature<br>from 275 K to 305 K the cis/trans ratio tends towards the trans conformer. This latter is less abundant<br>in the case of [Cu(L-Glu)2], because of the possible interaction of negative side chain carboxylate<br>anions with the water molecules axially bound, and for [Cu(L-Arg)(D-Glu)], probably owing to a possible<br>electrostatic interaction between the two opposite charged side chains which are on the same side of the<br>CuN2O2 coordination plane. Low temperature frozen solution EPR spectra run on these systems show<br>the presence of only one absorbing specie thus giving reason to the stabilization of one conformer over<br>the other, in particular, the cis conformer. There are no evident differences in the anisotropic Spin<br>Hamiltonian parameters derived from the frozen EPR solution spectra of these systems, which are<br>characterized by a tetragonally elongated octahedral stereochemistry. SWV measurements confirmed<br>the EPR spectroscopic data, actually giving rise to the observation of slightly asymmetrical peaks, which<br>revealed two near formal redox potentials assigned to the two conformers.
3 Records (3 escludendo Abstract e Conferenze). Impact factor totale: 11.251 (11.251 escludendo Abstract e Conferenze). Impact factor a 5 anni totale: 12.113 (12.113 escludendo Abstract e Conferenze).
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