The coordination chemistry of -butylcalix[8]arene with transition and lanthanide metal ions.

A survey of the literature and the Cambridge Structural Database reveals thirty nine -butylcalix[8]arene-supported transition (3d, limited to V-Cu) and lanthanide metal complexes ranging in nuclearity from one to eighteen, twenty of which are homometallic and nineteen of which are heterometallic. We provide a review of the coordination chemistry of these complexes, including our own work in the area. We also provide our thoughts and perspectives on the common structural themes observed, identify gaps in knowledge and evaluate how that may inform and direct future synthetic efforts.

Supramolecular assemblies derived from methyl-substituted cucurbit[5]uril and lanthanide nitrates.

Interaction of the lanthanide nitrates M(NO) (M = Gd, Eu) with methylcucurbit[5]uril (MeQ[5]) in the presence of transition metal chlorides (ZnCl and FeCl) in acidic media resulted in the isolation of the complexes [MeQ[5]Gd(HO)Cl Gd(HO)](ZnCl)∙Cl∙8.9H2O () and [MeQ[5]Eu(HO)Cl(HO)](FeCl) (). The molecular structures of  and  have been determined by single crystal X-ray crystallography, and reveal discrete complexes which are involved in dense stacking with adjacent MeQ[5]s linked via H-bonding and/or metal anions resulting in a supramolecular assembly.

Stellated cuboctahedron of Fe.

The solvothermal reaction of FeCl ⋅ 4HO and HTBC[4] in a basic dmf/EtOH solution affords an [Fe ] Keplerate conforming to a stellated cuboctahedron. Magnetic and heat capacity measurements reveal spin frustration effects arising from the high symmetry. A crossover between inverse and direct magnetocaloric effects is observed at ~10 K for applied-field changes lower than 3 T.

A bis-calix[4]arene-supported [CuII16] cage.

Reaction of 2,2'-bis--Bu-calix[4]arene (HL) with Cu(NO)·3HO and -methyldiethanolamine (Me-deaH) in a basic dmf/MeOH mixture affords [CuII16(L)(Me-dea)(μ-NO)(μ-OH)(dmf)(MeOH)(HO)](HL)·16dmf·4HO (4), following slow evaporation of the mother liquor. The central core of the metallic skeleton describes a tetracapped square prism, [Cu], in which the four capping metal ions are the Cu ions housed in the calix[4]arene polyphenolic pockets. The [CuII8] square prism is held together "internally" by a combination of hydroxide and nitrate anions, with the -methyldiethanolamine co-ligands forming dimeric [CuII2] units which edge-cap above and below the upper and lower square faces of the prism.

Engineered MOF-Enzyme Nanocomposites for Tumor Microenvironment-Activated Photodynamic Therapy with Self-Luminescence and Oxygen Self-Supply.

Photodynamic therapy (PDT) is a promising strategy for cancer treatment. However, its efficiency is hindered by three key parameters, namely, limited penetration depth of external light, tumor hypoxia, and self-aggregation of photosensitizers. Herein, we fabricated a novel "all-in-one" chemiluminescence-PDT nanosystem through the integration of an oxygen-supplying protein (hemoglobin, Hb) and a luminescent donor (luminol, Lum) in hierarchically engineered mesoporous porphyrinic metal-organic framework (MOF) nanoparticles.

A {GdNa} Molecular Quadruple-Wheel with a Record Magnetocaloric Effect at Low Magnetic Fields and Temperatures.

Reaction of Gd(OAc)·4HO, salicylaldehyde and CHONa in MeCN/MeOH affords [GdNa(OAc)(HCO)(CO)(HO)]·9HO.0.5MeCN (·9HO.

Regioselective electrophilic aromatic borylation as a method for synthesising sterically hindered benzothiadiazole fluorophores.

Regioselective stepwise phenylation of 4,7-diarylbenzo[][1,2,5]thiadiazole fluorophores has been achieved through a facile one-pot, three-step synthetic strategy involving sequential borylation, hydroxydechlorination and Suzuki-Miyaura cross-coupling reactions. Crucial to the selectivity was the use of BCl to regioselectively install a boronic acid group in the -position of only one of the diaryl groups. The subsequent introduction of -phenyl groups through Suzuki-Miyaura cross-coupling gave rise to twisted structures with hindered intramolecular rotation, providing a structural lever with which the fluorophore absorption and emission properties could be adjusted.

Controlled Hydrolysis of Phosphate Esters: A Route to Calixarene-Supported Rare-Earth Clusters.

Phosphate ester bonds are widely present in nature (e. g. DNA/RNA) and can be extremely stable against hydrolysis without the help of catalysts.

A ferromagnetically coupled pseudo-calixarene [Co] wheel that self-assembles as a tubular network of capsules.

Reaction of Co(OAc)·4HO and Hsal in a basic MeCN solution affords the hexadecanuclear wheel [Co(sal)(OAc)]·16MeCN (1·16MeCN) that displays ferromagnetic nearest neighbour exchange and has pseudo-calixarene character. Symmetry equivalent wheels self-assemble to form remarkable tubular networks of capsules in the extended structure.

Constructing "Closed" and "Open" {Mn} Clusters.

Use of the 1,3,5-tri(2-hydroxyethyl)-1,3,5-triazacyclohexane ligand, LH, in manganese chemistry affords access to two structurally related {Mn} clusters: a "closed" {Mn Mn } puckered square wheel of formula [MnL(LH)O(OH)(MeO)Br(imH)(HO)](Br) (; imH = imidazole) and an "open" {Mn } rod of formula [Mn LO(aibH)(aib)(MeO)(MeOH)](NO) (, aibH = 2-amino-isobutyric acid). In each case the triaza ligands, L/LH, direct the formation of {Mn} triangles with their N atoms preferentially bonding to the Jahn-Teller axes of the Mn ions. Subsequent self-assembly is dependent on the anion of the Mn salt and the identity of the organic coligand employed-the terminally bonded imidazole and the chelating/bridging amino acid.

Hybrid lanthanide double-deckers based on calixarene and polyoxometalate units.

Complementarity of calixarene (HL) and polyoxometalate ligands results in the first organic-inorganic [ML{MoO(OMe)(NO)}] (M = Y, Gd and Dy) hybrid, directing the formation of a distorted square-antiprismatic MO ligand field and resulting in slow relaxation of the magnetisation for the Dy derivative.

Correction: The coordination chemistry of -butylcalix[4]arene with paramagnetic transition and lanthanide metal ions: an Edinburgh Perspective.

Correction for 'The coordination chemistry of -butylcalix[4]arene with paramagnetic transition and lanthanide metal ions: an Edinburgh Perspective' by Lucinda R. B. Wilson , , 2022, DOI: 10.

Facile synthetic routes to bridge-functionalised calix[4]arenes.

Ring-opening of furans at the equatorial methylene bridge positions of a calix[4]arene gives access to a range of new molecules (in good yield) that have widespread potential impact in supramolecular chemistry amongst other areas.

The coordination chemistry of -butylcalix[4]arene with paramagnetic transition and lanthanide metal ions: an Edinburgh Perspective.

The calix[4]arene scaffold is an extremely versatile supramolecular platform that has found widespread use across many research areas due to its synthetic versatility, controllable conformation, and the presence of cavities or clefts for tailorable guest binding. The tetraphenolic lower-rim of -butylcalix[4]arene in the cone conformation is ideal for binding a variety of paramagnetic transition and lanthanide metals, and in this Perspective we review our endeavours in using such complexes as metalloligands in the synthesis of polymetallic clusters that have fascinating structural and magnetic properties. By varying reactants, stoichiometries and reaction or crystallisation conditions it is possible to access an incredible range of clusters, all of which show consistent trends in coordination preferences and assembly behaviours.

Oxidation state variation in bis-calix[4]arene supported decametallic Mn clusters.

The reaction of MnCl·4HO, HL (2,2'-bis--Bu-calix[4]arene) and NEt in a dmf/MeOH solvent mixture results in the formation of a mixed valent decametallic cluster of formula [MnII6MnIII4(L)(μ-OH)(μ-OH)(MeOH)(dmf)(MeCN)]·MeCN (3). Complex 3 crystallises in the monoclinic space group 2/ with the asymmetric unit comprising half of the compound. Structure solution reveals that the bis-calix[4]arene ligands are arranged such that one TBC[4] moiety in each has undergone inversion in order to accommodate a [MnIII4MnII6] metallic skeleton that describes three vertex-sharing [MnIII2MnII2] butterflies.

Phosphorylated-calix[4]arene double-deckers of single rare earth metal ions.

Combination of phosphoryl and calix[4]arene moieties in the same organic framework (LPO) directs the formation of homoleptic double-decker complexes [LnIII(LPO)2](OTf)3 for Ln = Tb and Dy, with the latter displaying slow relaxation of the magnetisation.

Exploiting complementary ligands for the construction of square antiprismatic monometallic lanthanide SMMs.

The methylation of p-tert-butylcalix[4]arene in the distal 1,3-phenolic sites provides the ligand H2L = {p-tert-butylcalix[4](OMe)2(OH)2arene} that enables construction of heteroleptic mononuclear lanthanide complexes. The reaction of (N(nBu)4)(acac) (Hacac = acetylacetone), MIIICl3 and H2L under Schlenk conditions results in the formation of a family of (N(nBu)4)[MIIIL(acac)2] complexes where M = Y (1), Gd (2), Tb (3) and Dy (4). The metal ions are eight-coordinate in distorted square-antiprismatic coordination geometries, resulting in slow relaxation of the magnetisation for the Tb derivative.

One-Pot Fabrication of Hollow Porphyrinic MOF Nanoparticles with Ultrahigh Drug Loading toward Controlled Delivery and Synergistic Cancer Therapy.

Hollow nanostructures have attracted significant research interest in drug delivery systems due to their high capacities for drug loading and unique physicochemical properties, showing great potential in specific biomedical applications. Herein, hollow porphyrinic metal-organic framework (H-PMOF) nanoparticles with a mesoporous spherical shell have been fabricated a facile self-sacrificial ZIF-8 nanoparticle template strategy. The H-PMOF nanoplatform not only demonstrates a greatly enhanced photodynamic therapy efficacy compared with nonhollow porphyrinic MOF nanoparticles but also can be used as a superior drug carrier to co-load doxorubicin (DOX) and indocyanine green (ICG) with an ultrahigh drug-loading capacity of 635%.

Self-Assembly of a Semiconductive and Photoactive Heterobimetallic Metal-Organic Capsule.

We report the synthesis of a novel metal-organic capsule constructed from six pyrogallol[4]arene macrocycles, which are switched together by 16 Fe and 16 Co ions. This supramolecular structure is the first instance of a spheroidal heterometallic nanocage assembled through a one-step metal-ligand coordination approach. This new assembly also demonstrates an important proof of concept through the formation of multiple heterometallic metal-metal interactions within the capsule framework.

Magneto-structural studies of an unusual [MnMnGd(OR)] partial cubane from 2,2'-bis--Bu-calix[4]arene.

Reaction of 2,2'-bis-p-tBu-calix[4]arene (H8L) with MnCl2·4H2O, GdCl3·6H2O and 2,6-pyridinedimethanol (H2pdm) affords [MnIIIMnIIGdIII(H3L)(pdmH)(pdm)(MeOH)2(dmf)]·3MeCN·dmf (3·3MeCN·dmf) upon vapour diffusion of MeCN into the basic dmf/MeOH mother liquor. 3 crystallises in the tetragonal space group P41212 with the asymmetric unit comprising the entire cluster. The highly unusual core contains a triangular arrangement of MnIIIMnIIGdIII ions housed within a [MnIIIMnIIGdIII(OR)4]4- partial cubane.

With complements of the ligands: an unusual S-shaped [Mn] assembly from tethered calixarenes.

The reaction between MnCl2·4H2O, 2,2'-bis-p-tBu-calix[4]arene (H8L1) and 2-(hydroxymethyl)pyridine (hmpH) in a basic dmf/MeOH solution results in the formation of the complex [MnIII10MnII4(L1)3(hmp)4(μ3-O)4(μ3-OH)2(MeOH)4(dmf)6](dmf)4 (6) upon vapour diffusion of petroleum ether into the mother liquor. The crystals are in the monoclinic space group C2/c, with the asymmetric unit (ASU) comprising one half of the molecule. The structure describes a large S-shaped cluster (∼40 Å top to tail) where the unusual syn and anti conformations of the calixarene ligands results in two binding pockets each containing a [MnIII5MnII2] moiety comprised of two perpendicular, vertex-sharing [Mn4] butterflies.