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List of Schemes
1.1 Representation of benzohydroxamic acid, BHA and salicylhydroxamic acid, SHA……… 3
1.2 Representations of the cavities of the 12-crown-4 and of a 12-metallacrown-4………... 4
1.3 Representation of a dinuclear complex of salicylhydroxamic acid………... 5
1.4 Representation of a 15-MC-5 of a Copper(II)/(S)-α-alaninehydroxamate.……….. 5
1.5 Hydroxamic acids classification (I) primary acid (II) secondary acid.………. 6
1.6 Z E isomerization for hydroxamic acids.………..……….. 6
1.7 Resonance structures for hydroxamic acids.………..………... 7
1.8 Intermolecular and intramolecular H-bonds for a generic hydroxamic acid in its Z conformation.………..……….………..………… 7
1.9 Possible ionization paths for hydroxamic acids...………..……… 8
1.10 Possible protonation derivatives of primary hydroxamic acids.………... 8
1.11 Metal ion (Mn+) {O,O} coordination by a generic hydroxamic acid.……… 9
1.12 Metal ion (Mn+ ) {N,O} coordination by a generic aminohydroxamic acid.……….. 9
1.13 Eigen and Tamm mechanism.………..………. 11
1.14 Eigen-Wilkins mechanism.………..………. 11
1.15 The solvent exchange process in the metal ion coordination sphere.……… 13
1.16 Possible formation mechanisms of a metal complex.………... 15
3.1 Reactive scheme for the Ni(II)/SHA system in SDS micellar solution.……… 35
3.2 Reactive scheme for the Ni(II)/SHA system, involving the slow effect, in SDS micellar solution………..……….………..………. 41
4.1 The structure assumed for the dinuclear complex of SHA that can represent the repetitive unit of a SHA based metallacrown.………..……… 48
4.2 Reactions involved in Fe(III) hydrolysis and aggregation processes.………... 50
4.3 Proposed molecular structures for the Fe(III) trimer.……… 54
LIST OF SCHEMES
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5.1 Representations of α-, β-, and γ-aminohydroxamic acids………. 71 5.2 Coordination modes of aminohydroxamic acids………..………. 71 5.3 Representation of (A) 12-MC-4 of Cu(II) and β-alaninehydroxamic acid (β-Alaha);
(B) 15-MC-5 of Cu(II), Nd(III) and (S)-α-alaninehydroxamic acid (α-Alaha).………... 72 5.4 Structures of the conceptual building blocks of metallacrowns: 12-MC-4 (A) and 15-MC-5
(B)……...………... 72
5.5 Reaction mechanism for Cu(II)/(S)-α-Alaha self-assembly to form the 12-MC-4 metallacrown 82 5.6 Possible structures for the Cu(II)/(S)-α-Alaha dimer.………..………. 95