The crystal structures of {LnCu₅}³⁺ (Ln = Gd, Dy and Ho) 15-metallacrown-5 complexes and a reevaluation of the isotypic Eu^III analogue

Abstract

Three new isotypic heteropolynuclear complexes, namely pentaaquacarbonatopentakis(glycinehydroxamato)nitratopentacopper(II)lanthanide(III) x-hydrate, [LnCu5(GlyHA)5(CO3)(NO3)(H2O)5]·xH2O (GlyHA2− is glycinehydroxamate, N-hydroxyglycinamidate or aminoacetohydroxamate, C2H4N2O2 2−), with lanthanide(III) (Ln III) = gadolinium (Gd, 1, x = 3.5), dysprosium (Dy, 2, x = 3.28) and holmium (Ho, 3, x = 3.445), within a 15-metallacrown-5 class were obtained on reaction of lanthanide(III) nitrate, copper(II) acetate and sodium glycinehydroxamate. Complexes 1–3 contain five copper(II) ions and five bridging GlyHA2− anions, forming a [CuGlyHA]5 metallamacrocyclic core. The Ln III ions are coordinated to the metallamacrocycle through five O-donor hydroxamates. The electroneutrality of complexes 1–3 is achieved by a bidentate carbonate anion coordinated to the Ln III ion and a monodentate nitrate anion coordinated apically to one of the copper(II) ions of the metallamacrocycle. The lattice parameters of complexes 1–3 are similar to those previously reported for an EuIII–CuII 15-metallacrown-5 complex with glycinehydroxamate of proposed composition [EuCu5(GlyHA)5(OH)(NO3)2(H2O)4]·3.5H2O [Stemmler et al. (1999). Inorg. Chem. 38, 2807–2817]. High-quality X-ray data obtained for 1–3 have allowed a re-evaluation of the X-ray data solution proposed earlier for the EuCu5 complex and suggest that the formula is actually [EuCu5(GlyHA)5(CO3)(NO3)(H2O)5]·3.5H2O.

Structural and Magnetic Properties of a {GdCu5}2Metallacrown Dimer with a Disulfonate Linker

“…The structure of the 15-metallacrown-5 fragments [GdCu 5 (GlyHA) 5 ] 3 + in complex 1 (Figure 2) is similar to that of several previously reported glycinehydroxamate Ln(III)-Cu(II) 15-metallacrowns-5, [52,53,[70][71][72] and discussion of structural features of 1 will thus be limited to supramolecular interactions of the [GdCu 5 (GlyHA) 5 ] 3 + cation with anions, sodium cations, and their solvating molecules. Details of the structural features of the metallamacrocyclic core {GdCu 5 } 3 + itself are given in the Supplementary Information section.…”

“…Substitution of anions in [GdCu 5 (GlyHA) 5 (CO 3 )(NO 3 )(H 2 O) 5 ] • 3.5H 2 O [52,53] by metathesis with an excess of the disulfonate linker Na 2 L (L 2À is 4,4'-bis(2sulfonatostyryl)biphenyl, Scheme 1) was carried out in a DMFwater solution and led to the formation of the centrosymmetric complex 1, {Na 2 (H 2 O) 8 [GdCu 5 (GlyHA) 5 (H 2 O) 4 L] 2 }L 2 • 2.5DMF…”

“…Here we report the synthesis, structure and magnetic properties of the dimeric complex {Na 2 (H 2 O) 8 [GdCu 5 (GlyHA) [52,53] with the Na + salt of the disulfonate linker. The experimental χ M T vs. T data were interpreted with two different previously proposed theoretical approaches.…”

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

“…these complexes feature, similar to 1, individual molecular complex cations (Katkova et al, 2015a,b;Pavlishchuk et al, 2011Pavlishchuk et al, , 2017aPavlishchuk et al, , 2018Pavlishchuk et al, , 2019Stemmler et al, 1999;Muravyeva et al, 2016;Kremlev et al, 2016), but a small number of oligomerized examples have also been reported (Pavlishchuk et al, 2017a(Pavlishchuk et al, , 2018.…”

“…Numerous research studies devoted to polynuclear 3d-4f assemblies have been stimulated by their non-trivial luminescence properties (Jankolovits et al, 2011;Maity et al, 2015), single-molecule magnet (SMM) behaviour (Dhers et al, 2016;Zangana et al, 2014) and their significant magnetocaloric effect (Pavlishchuk & Pavlishchuk, 2020;Zheng et al, 2014). 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).…”