Anion Encapsulation Drives the Formation of Dimeric Gd^III[15-metallacrown-5]³⁺ Complexes in Aqueous Solution

Abstract

Metallacrown complexes capable of sequestering dianions, as shown in the solid state, also exist in aqueous solution at neutral pH, as demonstrated by calorimetric and mass spectrometric data. The driving forces for the formation of these dimeric complexes in solution strongly depend on the chain length of the guest rather than its degree of unsaturation.

Peculiarities of crystal structures and photophysical properties of GaIII/LnIII metallacrowns with a non-planar [12-MC-4] core

“…31 With structural similarity to crown ethers, MCs are capable of binding a central metal ion through the hydroximate oxygen atoms. MCs have been extensively explored in the fields of selective ion recognition, [32][33][34][35][36][37][38] molecular magnetism [39][40][41][42][43][44][45][46][47] and magnetorefrigeration, 48 as well as contrast agents for magnetic resonance imaging (MRI). [49][50][51] In view of the creation of luminescent Ln III -based compounds, the unique MC scaffolds combine a large number of chromophores able to efficiently absorb and sensitize characteristic Ln III emission in the visible and NIR ranges as well as to protect Ln III from the sources of non-radiative deactivations.…”

pH‐Responsive Switching Properties of a Water‐Soluble Metallamacrocyclic Phenylalaninehydroximate La(III)–Cu(II) Complex: Insight into Tuning Protonation Ligand States

“…Nowadays, the popularity of water‐soluble polynuclear metallamacrocyclic Cu(II)‐Ln(III) complexes is largely due to their rich coordination chemistry, diverse properties and ease of synthesis . The remarkable feature of Cu(II)‐Ln(III) 15‐MC‐5 complexes is the deep color .…”

“…Nowadays, the popularity of water-soluble polynuclear metallamacrocyclic Cu(II)-Ln(III) complexes is largely due to their rich coordination chemistry, diverse properties and ease of synthesis. [11][12][13][14][15][16][17][18][19][20][21][22] The remarkable feature of Cu(II)-Ln(III) 15-MC-5 complexes is the deep color. [23][24][25][26] It should be pointed out that the observed ligand-field bands in visible region near 550 nm have provided the potential ability to obtain useful diagnostic information concerning the structures of transition metal ionpeptide complexes.…”

Complex formation of copper(ii), nickel(ii) and zinc(ii) with ethylophosphonoacetohydroxamic acid: solution speciation, synthesis and structural characterization

“…the number of metal ions and ligands, as well as pH, are provided. Taking into account the possible applications of MCs in a number of research fields (in particular, synthesis of porous MOFs for selective absorption of guest molecules, luminescent materials, selective molecular recognition agents) [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] over the last two decades their chemistry has largely expanded, revealing that a key aspect in the control of the MCs scaffolds' topology and geometry is a proper match between the metal ion and the ligand. 3,[20][21][22] Apart numerous hydroxamate ligands functionalized in α-or β-position by NH 2 -group (e.g.…”