Complexation Chemistry of Zirconium(IV), Uranium(VI), and Iron(III) with Acetohydroxamic Acid

Investigation of Zr(iv) and 89Zr(iv) complexation with hydroxamates: progress towards designing a better chelator than desferrioxamine B for immuno-PET imaging

“…For example, the N-methyl carbon of the E form syn to oxygen (d 36.14) is better shielded than the anti carbon of the Z form (d 36.89). This assignment is consistent with the previous 13 C NMR studies, which have shown that alkyl carbon atoms syn to amide oxygen are better shielded than the corresponding anti carbons. 10 In line with these 13 C assignments, the two methyl peaks at d 3.24 and 3.37 are assigned to the E and Z forms of the N-CH 3 respectively (Tables S4 and S5, ESI †).…”

“…This assignment is consistent with the previous 13 C NMR studies, which have shown that alkyl carbon atoms syn to amide oxygen are better shielded than the corresponding anti carbons. 10 In line with these 13 C assignments, the two methyl peaks at d 3.24 and 3.37 are assigned to the E and Z forms of the N-CH 3 respectively (Tables S4 and S5, ESI †). In contrast, all the 1 H and 13 C doublets associated with the Z and E rotamers of Me-AHA appear as singlets in Zr(Me-AHA) 4 since only the Z rotamer can form a bidentate complex with Zr 4+ (Fig.…”

“…A selection of calculated overall (log β) and stepwise (log K ) stability constants is available in Table 1. These values are in good agreement with the literature data for Zr(IV) hydroxamates complexes investigated by other experimental methodologies, 7,13 and are also in the same order of magnitude than those observed with Fe 3+ , known to form strong complexes with hydroxamic acids in various natural biological processes. 11 Speciation diagrams calculated from the complexation constants are available in ESI (Fig.…”

“…The experimental 1 H and 13 C NMR spectra of the free ligand (Fig. S4, ESI †) show the presence of Z and E rotamers of Me-AHA at room temperature due to the hindered rotation with respect to the C-N amide bond.…”

Removal of BTA Adsorbed on Cu: A Feasibility Study Using the Quartz Crystal Microbalance with Dissipation (QCMD) Technique

“…One such compound is acetohydroxamic acid (AHA, CH 3 -CO-NH-OH) that is known to be an excellent copper chelator. [21][22][23][24][25][26] It has a pKa 9.3 21,25,27,28 and the acetohydroxamate ion forms a 1:1 and 2:1 complex with cupric ions with a stability constant of 10 7.9 and 10 14 respectively. The feasibility of removal of BTA by AHA may be represented by the following reaction:…”