Europium and ytterbium complexes with o-iminoquinonato ligands: synthesis, structure, and magnetic behavior

Complexes of divalent ytterbium (1) and europium (2) with a dianionic o-amidophenolate ligand were prepared by both the direct reduction of 4,6-di-tert-butyl-N-(2,6-diisopropylphenyl)-o-iminobenzoquinone (dpp-IQ) and the salt metathesis reaction of potassium o-amidophenolate with LnI2 (Ln = Yb, Eu). Oxidation of o-amidophenolates 1, 2 with one equivalent of dpp-IQ as well as the salt metathesis reaction of potassium o-iminosemiquinolate with LnI2 afforded ligand mixed-valent o-iminosemiquinonato-amidophenolato complexes of trivalent ytterbium (3) and europium (4). All novel complexes 1-4 were fully characterized, including the solid state structures of 1 and 2 determined by single crystal X-ray diffraction. The magnetic properties of paramagnetic 2-4 were examined.

Niobium uptake by a [P8W48O184]40−macrocyclic polyanion

Incorporation of Nb into the [P₈W₄₈O₁₈₄]⁴⁰⁻anionic macrocyclic cavitand leads to formation of new Nb–W POMs. Inclusion of up to five {NbO(H₂O)}³⁺groups was observed. Solution speciation of the Nb-encapsulating macrocycles was studied by HPLC-ICP-AES and SAXS.

Halogen bonding-assisted assembly of bromoantimonate(v) and polybromide-bromoantimonate-based frameworks

Halogen bonding within bromo- and polybromoantimonates(v).

Correction: Niobium uptake by a [P8W48O184]40−macrocyclic polyanion

Correction for ‘Niobium uptake by a [P₈W₄₈O₁₈₄]⁴⁰⁻macrocyclic polyanion’ by Alexandra A. Shmakovaet al.,New J. Chem., 2019,43, 9943–9952.

Halogen bonding in the structures of pentaiodobenzoic acid and its salts

Structural characterization of pentaiodobenzoic acid (PIBA) and its salts was performed for the first time.

A Novel Family of Polyiodo-Bromoantimonate(III) Complexes: Cation-Driven Self-Assembly of Photoconductive Metal-Polyhalide Frameworks

In the presence of different cations, reactions of [SbBr₆ ]^3- and I₂ result in a new family of diverse supramolecular 1D polyiodide-bromoantimonate networks. The coordination number of Sb, as well as geometry of assembling {I_x }^n- polyhalide units, can vary, resulting in unprecedented structural types. The nature of I⋅⋅⋅Br interactions was studied by DFT calculations; estimated energy values are 1.6-6.9 kcal mol^-1 . Some of the compounds showed strong photoconductivity in thin films, suggesting multiple feasible applications in optoelectronics and solar energy conversion.

Host-Guest Binding Hierarchy within Redox- and Luminescence-Responsive Supramolecular Self-Assembly Based on Chalcogenide Clusters and γ-Cyclodextrin

Water-soluble salts of anionic [Re₆ Q₈ (CN)₆ ]^4- (Q=S, Se, Te) chalcogenide octahedral rhenium clusters react with γ-cyclodextrin (γ-CD) producing a new type of inclusion compounds. Crystal structures determined through single-crystal X-ray diffraction analysis revealed supramolecular host-guest assemblies resulting from close encapsulations of the octahedral cluster within two γ-CDs. Interestingly, nature of the inner Q ligands influences strongly the host-guest conformation. The cluster [Re₆ S₈ (CN)₆ ]^4- interacts preferentially with the primary faces of the γ-CD while the bulkier clusters [Re₆ Se₈ (CN)₆ ]^4- and [Re₆ Te₈ (CN)₆ ]^4- exhibit specific interactions with the secondary faces of the cyclic host. Furthermore, analysis of the crystal packing reveals additional supramolecular interactions that lead to 2D infinite arrangements with [Re₆ S₈ (CN)₆ ]^4- or to 1D "bamboo-like" columns with [Re₆ Se₈ (CN)₆ ]^4- and [Re₆ Te₈ (CN)₆ ]^4- species. Solution studies, using multinuclear NMR methods, ESI-MS and Isothermal titration calorimetry (ITC) corroborates nicely the solid-state investigations showing that supramolecular pre-organization is retained in aqueous solution even in diluted conditions. Furthermore, ITC analysis showed that host-guest stability increases significantly ongoing from S to Te. At last, we report herein that deep inclusion alters significantly the intrinsic physical-chemical properties of the octahedral clusters, allowing redox tuning and near IR luminescence enhancement.

Bromo- and Polybromoantimonates(V): Structural and Theoretical Studies of Hybrid Halogen-Rich Halometalate Frameworks

Cation-dependent reactions "[SbBr₆ ]^3- +Br₂ +HBr+CationBr_x " result in the formation of bromide/polybromide complexes with zero-, one-, two-, or three-dimensional supramolecular frameworks and different Br/Sb ratios (up to 11). Seven new compounds representing six structural types were characterized by XRD and thermogravimetric analysis and DFT calculations enabled estimation of the energies of the Br⋅⋅⋅Br contacts (1.1-4.6 kcal mol^-1 ).