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Multistability on the molecular scale level required for molecular devices can be realized using metallocomplexes with redox-active ligands such as o-quinones, o-quinoneimines and o-diimines as building blocks. Herein, we prepared four sterically shielded di-o-quinones bridged with a dioxyarylene linker with different topology and steric characteristics and studied the properties of their reduced species. EPR spectroscopy investigation revealed that the intramolecular exchange interaction between paramagnetic centers in the biradical dianion derivatives of synthesized di-o-quinones predominantly depends on the steric environment of the linker and the nature of the counter cation at the dioxolene site, and the topology of the linker plays a secondary role. [ABSTRACT FROM AUTHOR]

Six new coordination polymers (CPs) of cadmium based on an extended anilate-type ligand, 4,4′-(1,4-phenylenebis(azanylylidene))bis(3,6-di-tert-butyl-2-hydroxycyclohexa-2,5-dienone) (H2L), have been synthesized. The series of coordination polymers includes [Cd(L)(DMF)] (1), 1D-CP [Cd(L)(dipy-1)]·2DMF (2A) and 2D-CP [Cd(L)(dipy-1)]·DMF (2B), [Cd2(L)2(dipy-2)(DMF)2] (3), [Cd(HL)(CH3COO)(dabco)] (4) and [Cd(L)(ur)2]·(H2L) (5) (where L – deprotonated form of H2L, DMF – N,N′-dimethylformamide, dipy-1 – 4,4′-trimethylenedipyridine, dipy-2 – 4,4′-dipyridyl, dabco – 1,4-diazabicyclo[2.2.2]octane, ur – urotropine). The crystal structure and thermal decomposition of 1D- and 2D-coordination polymers are reported. The structural diversity of the synthesized compounds was found to depend on the additional neutral donor ligands in the cadmium coordination sphere. Thus, the introduction of the flexible N-donor ligand dipy-1 into the cadmium coordination sphere leads to the formation of two types of coordination polymers (1D and 2D). The use of the rigid ligand dipy-2 promotes the formation of "honeycomb" 2D-CPs. The use of shorter N-donor ligands dabco and ur leads to linear derivatives in which the ligands being coordinated by cadmium don't act as "crosslinkers" of the chains in the network. [ABSTRACT FROM AUTHOR]

We report the synthesis, structures, and magnetic and luminescence properties of a series of new monoand dinuclear Er3+ complexes derived from sterically demanding aryloxide and fluorinated alkoxide ligands: [4-tBu-2,6-(Ph2CH)2C6H2O]3Er(THF) (1), [(C6F5)3CO]3Er(Me3SiOH) (2), [(C6F5)3CO]3Er[(Me3Si)2NH] (3), [(C6F5)3CO]3Er(C6H5CH3) (4), [(C6F5)3CO]3Er(o-Me2NC6H4CH3) (5) and {[Ph(CF3)2CO]2Er(μ²-OC (CF3)2Ph)}2 (6). In compounds 1, 2, and 4, the Er3+ ion is four-coordinated and adopts a distorted trigonal pyramidal geometry, while in 3, 5, and 6, the coordination geometry of Er3+ is impacted by the presence of several relatively short Er...F distances, making them rather 6-coordinated. All compounds behave as field-induced Single Molecule Magnets (SMMs) and exhibit an Er3+ characteristic near infrared (NIR) emission associated with the 4I13/2 → 4I15/2 transition with a remarkably long lifetime going up to 73 µs, which makes them multifunctional luminescent SMMs. The deconvolution of the NIR emission spectra allowed us to provide a direct probe of the crystal field splitting in these compounds, which was correlated with magnetic data. [ABSTRACT FROM AUTHOR]

Ditopic di-o-quinone with a resorcinol bridge exhibits the ability to self-assemble in a reaction with copper, giving a cage-like binuclear complex that, due to the cofacially placed metal ions, is capable of encapsulation of different solvent molecules as guest ligands. Notably, the geometry of the internal cavity of this complex adjusts depending on the coordinating properties of the encapsulated molecule (mono- or bidentate). A feature of this species is that the cage-forming units are copper(II) bis-semiquinonate moieties, capable of undergoing ligand-centered redox transformations. Electrochemical and EPR spectroscopy studies showed that there is a channel for intramolecular electronic exchange interactions between the redox centres of the molecule. [ABSTRACT FROM AUTHOR]

Bis(phenolate) ligands with benzimidazole‐2‐ylidene (L1) and tetrahydropyrimidine‐2‐ylidene (L2) linkers proved to be suitable coordination environments for the synthesis of isolable Sc3+ chloro and alkyl complexes. The treatment of Sc(CH2SiMe3)3(THF)2 with equimolar amounts of [L1,2H3]Cl afforded chloro complexes L1,2ScCl(solv)2 (solv=THF, Py) in 76–85 % yields. L1,2ScCl(THF)2 were also prepared by the salt metathesis reactions of ScCl3 with [L1,2]Na2 generated from [L1,2H3]Cl and 3 equiv. of NaN(SiMe3)2 (−40 °C, THF) and isolated in somewhat lower yields (68–73 %). L2ScCl(THF)2 was subjected to the alkylation reaction with LiCH2SiMe3 affording alkyl derivative [L2Sc(CH2SiMe3)]2. This compound can be alternatively prepared by the subsequent reactions of [L2H3]Cl with equimolar amount of NaN(SiMe3)2 and Sc(CH2SiMe3)3(THF)2. In the dimeric alkyl compound [L2Sc(CH2SiMe3)]2, one of the phenoxide groups of the dianionic ligand is coordinated to one scandium center, while the second one features μ‐bridging coordination with two metal centers. [ABSTRACT FROM AUTHOR]

We report the synthesis of Ln3+ nitrate [Ln(Tpm)(NO3)3] ⋅ MeCN (Ln=Yb (1Yb), Eu (1Eu)) and chloride [Yb(Tpm)Cl3] ⋅ 2MeCN (2Yb), [Eu(Tpm)Cl2(μ‐Cl)]2 (2Eu) complexes coordinated by neutral tripodal tris(3,5‐dimethylpyrazolyl)methane (Tpm). The crystal structures of 1Ln and 2Ln were established by single crystal X‐ray diffraction, while for 1Yb high resolution experiment was performed. Nitrate complexes 1Ln are isomorphous and both adopt mononuclear structure. Chloride 2Yb is monomeric, while Eu3+ analogue 2Eu adopts a binuclear structure due to two μ2‐bridging chloride ligands. The typical lanthanide luminescence was observed for europium complexes (1Eu and 2Eu) as well as for terbium and dysprosium analogues ([Ln(Tpm)(NO3)3] ⋅ MeCN, Ln=Tb (1Tb), Dy (1Dy); [Ln(Tpm)Cl3] ⋅ 2MeCN, Ln=Tb (2Tb), Dy (2Dy)). [ABSTRACT FROM AUTHOR]