Investigation of Chromophoric Behavior of Water‐Soluble La^III‐Cu^II Polynuclear Metallamacrocyclic 15‐MC‐5 Complex

Abstract

The visible absorption spectrum of the water soluble polynuclear metallamacrocyclic LaIII‐CuII complex La(H2O)3[15‐MCCu(II)Phalaha‐5](Cl)3 (1) based on α‐phenylalaninehydroxamic acid appears to be solvent‐ and ion‐sensitive. The copper(II) d–d transitions of the complex 1 dissolved in methanol, ethanol, water, dimethylformamide, dimethylsulfoxide, pyridine, and N‐methylpyrrolidone were studied. The chromophoric behavior of complex 1 was investigated in the presence of the Cl–, Br–, I–, HSO4–, CO32–, HCO3–, H2PO4–, CN–, SCN–, and N3– anions. A considerable change of the d–d transition of the central copper(II) atom was observed for the strongly coordinating cyanide and azide anions. In the presence of HSO4–, the d–d intensity of copper(II) also decreased significantly. The molecular structure of La2(H2O)7[15‐MCCu(II)Phalaha‐5]2(SO4)4 (2), obtained as result of the substitution of the coordinated water molecules in 1 by the SO42– anions, was investigated by X‐ray crystallography.

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

“…In the visible region of the spectra a broad band with a maximum at 575 nm ( ε = 406 M –1 cm –1 ) is attributed to Cu(II) d‐d transition band. This broad band is responsible for the characteristic dark blue color of 1 , that is observed in all previously reported water‐soluble Cu(II)‐Ln(III) aminohydroximate complexes , , , . Note, that the broad bands in the region above 600 nm are quite common for copper(II) complexes with square pyramidal or distorted square pyramidal geometries .…”

“…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 .…”

Synthesis and Molecular Structure of the First Metallamacrocyclic Bi(III)-Cu(II) 15-MC-5 Complex Derived from Pyrazinohydroxamic Acid

“…[4] The first planar 15-MC-5 uranyl complex was obtained by self assembly of picolinehydroxamic acid with Cu 2+ and UO 2 2+ ions. [15] A number of MCs were prepared in a similar way in the following few years, leading to the isolation of 15-MC-5 of copper and aminohydroxamic acids encapsulating Ln 3+ , [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Y 3+ , [31][32][33] and non-transition metals Ca 2+ , [33][34][35] Na + , [31] Ag + , [31] Pb 2+ , [31] and Hg 2+ . [31] Following our interest in Ln(III)-Cu(II) 15-MC-5 metallacrowns with aminohydroxamic ligands, we report now on a metallamacrocyclic complex constructed from Cu 2+ and Bi 3+ metal centers and aminohydroxamic moieties.…”

Crystal structure of a TbIII–CuII glycinehydroxamate 15-metallacrown-5 sulfate complex

“…The 15-metallacrown-5 complexes are 3d-4f metallamacrocyclic assemblies, which can be easily obtained from one-step reactions between an -substituted hydroxamic acid and the corresponding salts of transition metals and lanthanides (Stemmler et al, 1999;Pavlishchuk et al, 2011Pavlishchuk et al, , 2019. Compounds bearing 15-metallacrown-5 {LnCu 5 } 3+ units have demonstrated the ability to serve as sensors (Zabrodina et al, 2018), can absorb and adsorb various small molecules (Lim et al, 2010;Pavlishchuk et al, 2014;Ostrowska et al, 2016) and display SMM behaviour (Wang et al, 2019(Wang et al, , 2021Zaleski et al, 2006;Wu et al, 2021). Taking into account the fact that 15-metallacrowns-5 are also suitable building blocks for the generation of porous coordination polymers and discrete assemblies (Pavlishchuk et al, 2017a(Pavlishchuk et al, ,b, 2018, the synthesis of ISSN 2056-9890 new examples of this class of metallamacrocyclic assemblies and studies of their structural features are of particular interest.…”