619-44-3Relevant articles and documents
Flexible bifunctional monoethylphosphonate/carboxylates of Zn(ii) and Co(ii) reinforced with DABCO co-ligand: paradigmatic structural organization withpcutopology
Boldog, Ishtvan,G?kpinar, Serkan,Gil-Hernández, Beatriz,Goldman, Anna,Heering, Christian,Janiak, Christoph,Millan, Simon
, p. 2933 - 2944 (2020)
Two novel isostructural phosphonate-monoethylcarboxylate MOFs with the structural formula of [M2(EtBCP)2(DABCO)0.5]·2DMA (M = Zn (2), Co (3); H2EtBCP =O-ethyl-P-(4-carboxyphenyl)phosphonic acid, DABCO = 1,4-diazabicyclo[2.2.2]octane, DMA =N,N-dimethylacetamide) were synthesized and characterized. The frameworks of2and3are sustained by {Zn2(PO2(OEt))2}nmetal-phosphonate- and DABCO-extended {Zn2(COO)4(DABCO)}npaddle-wheel carboxylate chain-SBUs. The chains providing connectivity in three, mutually orthogonal directions are running parallel and are combined in a framework, which could be interpreted as having apcutopology. The simple structure-organization principle, which suggests the possibility of the elongation of the bifunctional ligand with scaling in two directions, allows to view the structures of2and3as prototypes for an isoreticular series. The porosity of both compounds, based on a relatively short ligand, is low: no adsorption of N2was registered, however, CO2is adsorbed readily allowing to estimate the surface area at ~330 m2g?1(~900-1060 m2g?1geometric estimate). The compounds demonstrate a two-step CO2adsorption isotherm both at 195 K (0-1 bar) and 298 K (0-20 bar). The adsorption isotherms are characterized by a gradual (type “F-I”), albeit still relatively steep onset of the second step, associated with structural flexibility/bistability. The estimated pore volumes at the start of the transformation (195 K) for2and3are ~0.11 (0.08P/P0) and 0.12 cm3g?1(0.12P/P0) respectively, which corresponds considerably well to the geometrically calculated accessible volume of ~0.07 cm3g?1for the experimental structure (3.3 ? probe diameter). The structural prerequisites of the observed flexibility of the framework, which might be associated with the non-planarity of the metal-phosphonate moieties, acting as ‘levers’ for propagating mechanical stress, are discussed.
Field-induced single-ion magnets exhibiting tri-axial anisotropy in a 1D Co(ii) coordination polymer with a rigid ligand 4,4′-(buta-1,3-diyne-1,4-diyl)dibenzoate
C. Silva, Henrique,Ferreira, Glaucio B.,Guedes, Guilherme P.,Matos, Catiúcia R. M. O.,Nunes, Wallace C.,Ronconi, Célia M.,Sarmiento, Charlie V.
, p. 15003 - 15014 (2021/11/17)
Herein a 1D Co(ii) coordination polymer of formula [Co(η1-L1)(η2-L1)(py)2(H2O)]n (CoCP) has been synthesised using the rigid H2L1 proligand, containing a long spacer bearing two triple bonds. Single-crystal X-ray diffraction showed that Co(ii) adopts a distorted octahedral geometry. The state-averaged complete active self-consistent field (SA-CASSCF) calculation showed that the ground state of CoCP is a high spin quartet with a highly multiconfigurational character of its electronic structure. Due to the large intra- and intermolecular distances between the spin carriers, the magnetic interactions are negligible and the zero-field splitting (ZFS) effects of cobalt(ii) ions are predominant. This behavior was confirmed by direct current (DC) magnetic measurements and theoretical calculations using the broken-symmetry approach. Quantum chemical calculations indicate that CoCP has a negative axial component possessing mixed tri-axial anisotropy. The DC magnetic susceptibility data were fitted with a Griffith-Figgis Hamiltonian and the obtained parameters are in good agreement with those simulated by the ab initio calculation. Alternating current (AC) magnetic measurements showed a field induced slow magnetic relaxation in CoCP, which is attributed to the hyperfine interaction effects.
Method for preparing iodo-benzoic acid (ester) by improving moral Michael reaction
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Paragraph 0024; 0037-0038, (2021/11/03)
The invention discloses a method for preparing iodo-benzoic acid (ester) by improving a moral reaction, and belongs to the technical field of organic synthesis. The method comprises the following steps: preparing and separating the diazonium tetrafluoroborate through diazotization of aminobenzoic acid (ester) and then performing iodination reaction with the iodinated reagent in an organic medium to obtain the corresponding iodo carboxylic acid (ester). The iodo-benzoic acid (ester) prepared by the method has high purity. The method has the advantages of good quality and simple post-treatment, and the product yield reaches 70 - 90%.