title: Unexpected formation of a copper(II) 12-metallacrown-4 with (S)-glutamic-gamma-hydroxamic acid: a thermodynamic and spectroscopic study in aqueous solution.
abstract: The equilibria of copper(II) with (S)-glutamic-gamma-hydroxamic acid (H2L) were investigated in aqueous solution by different techniques: glass electrode potentiometry; calorimetry; VIS and CD spectrophotometry; and ES-MS. An unexpected pentacopper(II) 12-metallacrown-4 [Cu5L4H(-4)](2-) was detected, analogous to those well known formed by alpha- and beta-aminohydroxamic acids, but of lower stability. Another five species were found: [CuLH]+; [CuL2H2]; [Cu2L2]; [CuL2H]-; and [CuL2]2-. Their structures are proposed based on both spectroscopic and calorimetric data.
authors.affiliation: Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Universita di Parma, Parco Area delle Scienze, 17A, 43100 Parma, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Tegoni
authors.forename: Francesco
authors.initials: F
authors.lastname: Dallavalle
authors.forename: Barbara
authors.initials: B
authors.lastname: Belosi
authors.forename: Maurizio
authors.initials: M
authors.lastname: Remelli
mesh_terms: D002151:Calorimetry; D003300:Copper / Q000737:chemistry*; D043844:Crown Ethers / Q000737:chemistry*; D005971:Glutamates / Q000737:chemistry*; D006877:Hydroxamic Acids / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D011199:Potentiometry; D012996:Solutions; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D043844:Crown Ethers; D005971:Glutamates; D006877:Hydroxamic Acids; D009942:Organometallic Compounds; D012996:Solutions; C050614:glutamate-gamma-hydroxamic acid; D003300:Copper