Square Grid Metal–Chloranilate Networks as Robust Host Systems for Guest Sorption

Abstract

Reaction of the chloranilate dianion with Y(NO3)3 in the presence of Et4N+ in the appropriate proportions results in the formation of (Et4N)[Y(can)2], which consists of anionic square‐grid coordination polymer sheets with interleaved layers of counter‐cations. These counter‐cations, which serve as squat pillars between [Y(can)2] sheets, lead to alignment of the square grid sheets and the subsequent generation of square channels running perpendicular to the sheets. The crystals are found to be porous and retain crystallinity following cycles of adsorption and desorption. This compound exhibits a high affinity for volatile guest molecules, which could be identified within the framework by crystallographic methods. In situ neutron powder diffraction indicates a size‐shape complementarity leading to a strong interaction between host and guest for CO2 and CH4. Single‐crystal X‐ray diffraction experiments indicate significant interactions between the host framework and discrete I2 or Br2 molecules. A series of isostructural compounds (cat)[MIII(X‐an)2] with M=Sc, Gd, Tb, Dy, Ho, Er, Yb, Lu, Bi or In, cat=Et4N, Me4N and X‐an=chloranilate, bromanilate or cyanochloranilate bridging ligands have been generated. The magnetic properties of representative examples (Et4N)[Gd(can)2] and (Et4N)[Dy(can)2] are reported with normal DC susceptibility but unusual AC susceptibility data noted for (Et4N)[Gd(can)2].

Crystal structures of 4-bromo-2-formyl-1-tosyl-1H-pyrrole, (E)-4-bromo-2-(2-nitrovinyl)-1-tosyl-1H-pyrrole and 6-(4-bromo-1-tosylpyrrol-2-yl)-4,4-dimethyl-5-nitrohexan-2-one

“…In each of the compounds reported here, a multitude of unremarkable interactions around the van der Waals limit are observed to constrain individual molecules. The presence of C-HÁ Á ÁO interactions would likely be unremarkable if not for the chelate motif -these so-called weak interactions can be far stronger with partial charge separation, such as in a sulfonyl, and when occurring at multiple preorganized sites simultaneously (Kingsbury et al, 2019). Collection of multiple crystal structures along the synthetic pathway of organic compounds is, we believe, good practice to assist data science investigations, and offers potential insight into the electronic structure of intermediates (Senge & Smith, 2005).…”

Redox Activity as a Powerful Strategy to Tune Magnetic and/or Conducting Properties in Benzoquinone-Based Metal-Organic Frameworks

“…Furthermore, when hydrogens at the 3 and 6 position are replaced with different substituents (halogen atoms or functional groups), they are better known in the literature as anilic acids, formulated as H 2 X 2 C 6 O 4 (H 2 X 2 An), where X indicates the substituent and C 6 O 4 indicates the anilate moiety (An) [2,42,43]. When the anilic acids are in their dianionic form, i.e., anilates, they act as valuable linkers for transition [44][45][46][47][48][49][50][51] and lanthanide metal nodes [52][53][54][55][56][57][58] to build materials showing a combination of fascinating physical properties and redox states (vide infra). All these features make them interesting molecular building blocks for constructing a large variety of novel supramolecular frameworks [49,59], as shown in Figure 1.…”

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

“…The introduction of different substituents in the 3 and 6 positions of the quinoid ring allows for a wide range of variations in their electronic and steric properties. Most commonly, researchers use chlorine [ 16 , 19 , 20 ], bromine [ 17 , 21 , 22 ], fluorine [ 23 , 24 ], nitro [ 25 , 26 ] and cyano-substituted [ 22 , 27 , 28 ] anilate ligands. The first paper on the use of 3,6-di-tert-butyl-2,5-dihydroxy-para-benzoquinone in the construction of 2D layered lanthanum MOFs was published [ 29 ].…”

“…Lanthanide MOFs/CPs are of great interest for their outstanding optical and magnetic properties [ 4 , 6 , 22 , 28 , 30 , 31 , 32 , 33 ]. They may appear as multifunctional materials for electro-optical, data storage, and sensing applications [ 5 , 27 , 34 , 35 , 36 ]. The first examples of heteroleptic NIR-Emitting Yb III /anilate-based coordination polymer nanosheets were prepared recently using terephthalic dicarboxylate coligands [ 7 ].…”