160248-28-2Relevant articles and documents
Syntheses and Crystal Structures of Two Cadmium Methanetetrabenzoates Featured by Open Framework and Infinite Layers
Harms, Sven,K?ferstein, Roberto,G?rls, Helmar,Robl, Christian
, p. 912 - 918 (2019/06/27)
Colorless single crystals of Cd2[μ8-MTB]·3H2O·DMF (1) were prepared in DMF/H2O solution [1: space group C2/c (no. 15) with a = 1821.30(6), b = 2175.08(6), c = 1269.87(4) pm, β = 129.684(1)°]. The connection between the methane-p-benzoate tetraanions (MTB4–) and the Cd2+ cations leads to a three-dimensional framework with channels extending along [110] and [110] with openings of 670 pm × 360 pm. The channel-like voids accommodate water molecules and N,N-dimethylformamide (DMF) molecules not bound to Cd2+. Colorless single crystals of [Cd4(2,2′-bipy)4(μ7-MTB)2]·7DMF (2) were prepared in DMF in the presence of 2,2′-bipyridine [2: space group P1 (no. 2) with a = 1224.84(4), b = 1418.85(5), c = 2033.49(4) pm, α = 85.831(2)°, β = 88.351(2)°, γ = 68.261(1)°]. The coordination of MTB4– to Cd2+ results in infinite layers parallel to (001). The layers, not connected by any hydrogen bonds, contain small openings of about 320 pm × 340 pm.
Flexible porous molecular materials responsive to CO2, CH4 and Xe stimuli
Bassanetti, Irene,Bracco, Silvia,Comotti, Angiolina,Negroni, Mattia,Bezuidenhout, Charl,Canossa, Stefano,Mazzeo, Paolo Pio,Marchió, Luciano,Sozzani, Piero
supporting information, p. 14231 - 14239 (2018/08/04)
In the search for flexible molecular crystals endowed with porosity, we achieved the fabrication of expandable crystalline prototypal structures, which allow the absorption of gases, without modifying the crystal architecture. The design brings together highly symmetrical tetrahedral elements to construct swellable porous adamantoid frameworks through co-operation of eight surrounding hydrogen bonds mounted on conformationally flexible groups. The flexibility of the porous crystals manifests itself in response to stimuli of selected gases, which promote reversible conformational changes, inducing breathing in the molecular structure. The backbone of the reticular construction is based on the formation of the carboxylic dimers, which project outwards from the tetrahedral molecular core to consolidate the 3D framework. Contact with proper gases such as CO2, Xe and hexane triggers a 56-70% enlargement of the channel cross-section. The accommodation of CO2 and Xe in the channel chambers was revealed by synchrotron-light X-ray diffraction, combined with molecular dynamics and density functional theory (DFT) theoretical calculations. Rare experimental observations of xenon dynamics, in which Xe diffuses along the channels and experiences different chamber orientations in the crystal, were gathered by analysing 129Xe NMR chemical shift anisotropy profiles, which encode the shape and orientation of each visited cavity along the channel. The jump rate and activation energy experienced was uniquely established by exploring Xe atoms in their diffusional path. Nitrogen showed a low affinity to the matrix and was unable to enlarge the pores, thus it was excluded from the restrictive pores of the empty crystal. Given the properties of molecular crystals, it is possible to outline some advantageous aspects, such as simple design, easy self-assembly, solubility, reversible gas uptake and absence of metal ions, and they can thus be considered for eco-friendly gas capture and separation.
EPR, 1H, and 13C ENDOR Studies of a Quintet-State 13C-Labeled Galvinoxyl-Type Tetraradical
Kirste, Burkhard,Grimm, Michael,Kurreck, Harry
, p. 108 - 114 (2007/10/02)
The syntheses of unlabeled and fourfold 13C-labeled tetraphenylmethane tetrakisgalvinols are described.Different paramagnetic species, i.e., a double-state monoradical, a triplet-state biradical, a quartet-state triradical, a quintet-state tetraradical, c
