Glycols in the Synthesis of Zinc-Anilato Coordination Polymers

We report the synthesis, structural investigation, and thermal behavior for three zinc-based 1D-coordination polymers with 3,6-di-tert-butyl-2,5-dihydroxy-p-benzoquinone, which were synthesized in the presence of different glycols. The interaction of zinc nitrate with glycols, followed by using the resulting solution in solvothermal synthesis with the anilate ligand in DMF, makes it possible to obtain linear polymer structures with 1,2-ethylene or 1,2-propylene glycols coordinated to the metal. The reaction involving 1,3-propylene glycol under similar conditions gives a crystal structure that does not contain a diol. The crystal and molecular structures of the synthesized compounds were determined using single crystal by X-ray structural analysis. The influence of glycol molecules coordinated to the metal on the thermal destruction of synthesized compounds is shown.

Complexes of Metal Halides with Unreduced o-(Imino)quinones

A series of complexes of metal halides with unreduced quinone-type ligands have been synthesized and characterized in detail. The 3,6-di-tert-butyl-o-benzoquinone (1) and 4,6-di-tert-butyl-N-aryl-substituted o-iminobenzoquinones (2-5) (aryl is 2,6-dimethylphenyl in 2, 2-methyl-6-ethylphenyl in 3, 2,6-diethylphenyl in 4, and 2,6-diisopropylphenyl in 5) were used to obtain the molecular complexes with metal 12 group halides as well as with indium(III) iodide. The molecular structures of five complexes, bearing an unreduced form of redox-active ligand, have been established by single-crystal X-ray analysis. The spectral data, electrochemical measurements, and DFT calculations indicate the significant transformations of the molecular orbitals of 1-5 upon complexation with Lewis acids. The reduction potentials of o-(imino)quinones in complexes with metal halides shift into the anodic region versus uncoordinated ones. The choice of metal halide allows varying the shift magnitude up to 1.7 V in 2·CdI₂. The change of the oxidizing ability of the 1-5 upon coordination with Lewis acids enables the oxidation of mercury and ferrocene, infeasible for free ligands.

Magnesium and Nickel Complexes with Bis(p-iminoquinone) Redox-Active Ligand

Abstract

Poorly soluble in the most part of organic solvents dimeric complexes $${\text{M}}{{{\text{g}}}_{{\text{2}}}}{\text{L}}_{2}^{2}$$·4DMF (I) and $${\text{N}}{{{\text{i}}}_{{\text{2}}}}{\text{L}}_{2}^{2}$$·4DMF (II) (L is 4,4'-(1,4-phenylenebis(azanylylidene))bis(3,6-di-tert-butyl-2-hydroxycyclohexa-2,5-dien-1-one dianion)) are synthesized by the reactions of magnesium and nickel acetates with the ditopic redox-active ligand of the hydroxy-para-iminoquinone type in a DMF solution. The molecular and crystal structures of the synthesized compounds are determined by X-ray diffraction analysis (CIF files CCDC nos. 2045665 (I) and 2045666 (II·3DMF)). The thermal stability is studied by thermogravimetry. The redox-active character of the organic bridging ligand in the dimeric complexes $${\text{M}}{{{\text{g}}}_{{\text{2}}}}{\text{L}}_{2}^{2}$$·4DMF and $${\text{N}}{{{\text{i}}}_{{\text{2}}}}{\text{L}}_{2}^{2}$$·4DMF is confirmed by the data of solid-phase electrochemistry.

Heteroleptic LaIII Anilate/Dicarboxylate Based Neutral 3D-Coordination Polymers

Three new 3D metal-organic frameworks of lanthanum based on mixed anionic ligands, [(La2(pQ)2(BDC)4)·4DMF]n, [(La2(pQ)2(DHBDC)4)·4DMF]n, [(La2(CA)2(BDC)4)·4DMF]n (pQ-dianion of 2,5-dihydroxy-3,6-di-tert-butyl-para-quinone, CA-dianion of chloranilic acid, BDC-1,4-benzenedicarboxylate, DHBDC-2,5-dihydroxy-1,4-benzenedicarboxylate and DMF-N,N'-dimethylformamide), were synthesized using solvothermal methodology. Coordination polymers demonstrate the rare xah or 4,6T187 topology of a 3D framework. The homoleptic 2D-coordination polymer [(La2(pQ)3)·4DMF]n was obtained as a by-product in the course of synthetic procedure optimization. The thermal stability, spectral characteristics and porosity of coordination polymers were investigated.

2D-metal–organic coordination polymers of lanthanides (La(iii), Pr(iii) and Nd(iii)) with redox-active dioxolene bridging ligands

2D-coordination redox-active networks bearingt-Bu-substituted anilic bridged ligands and lanthanide ions were synthesized and characterized.