Practical Porous Matrix for Molecular Structure Determination of General Liquid Chemicals

A practical porous crystalline matrix for molecular structure determination of a wide range of liquid chemicals has been set up. We herein report proof-of-concept research on the temperature-dependent single-crystal-to-single-crystal (SCSC) guest exchange of the <i>P</i>- and <i>M</i>-helix-enantiomeric multilayered ensemble with flexible open-channels of the shortest diameter, 4.4 × 4.4 Ų. This landmark ensemble is, to the best of our knowledge, the most efficient, practical, tolerant, and reproducible porous matrix for single crystal structure determination of general liquid compounds via easy SCSC guest exchange without any desolvation process. The innovative channel behaves in a guest-dependent flexible response manner and enables scientists to solve structures of a wide range of liquid chemicals. This paper reports the molecular structures of 41 liquid chemicals including chiral and natural compounds via guest exchange at >75% success rate

Suprachannels via a Molecular Array of 2D Networks: Solvent Effects, Anion Exchange, and Physicochemical Properties of Silver(I) Complexes Bearing <i>N</i>,<i>N</i>′,<i>N</i>″‑Tris(2-pyridinylethyl)-1,3,5-benzenetricarboxamide

The solvent effects on suprachannel formation via a molecular array of 2D networks were studied. The basic structure of the [Ag₃L₂]­(X)₃ (X^– = NO₂^–, NO₃^–) 2D network consists of hexagonal (Ag₆L₆) motifs formed via self-assembly of Ag­(I) with <i>C</i>₃-tridentate <i>N</i>-donors. The 2D networks are arranged in an eclipsed mode in aqueous solution, thus forming suprachannels (5.2 × 7.3 Ų, 6.2 × 7.7 Ų) of [Ag₃L₂(H₂O)₂]­(X)₃, whereas they are arranged in a staggered <i>abab</i>... mode in nonaqueous solution, thus forming semisuprachannels (3.1 × 5.1 Ų) of [Ag₃(NO₃)₂L₂]­(NO₃). The suprachannel structure of [Ag₃L₂(H₂O)₂]­(NO₃)₃ is soluble in methanol; contrastingly, the semisuprachannel structure of [Ag₃(NO₃)₂L₂]­(NO₃) is insoluble in that solvent. In the present study, significant differences in molecular recognition and anion exchangeability between [Ag₃L₂(H₂O)₂]­(NO₃)₃ and [Ag₃(NO₃)₂L₂]­(NO₃) were found

Crystals of Ni₆L₁₂ Ellipsoidal Tubes as Single-Crystal-to-Single-Crystal Adsorption Matrix: Penetrative Study of Self-Assembled Crystals vs Guest-Exchanged Crystals

Informative similarities/differences between self-assembled and single-crystal-to-single-crystal (SCSC) guest-exchanged crystals based on both the molecular structure and adsorption nature are observed. The self-assembly of Ni(ClO4)2 with a dicyclopentyldi(pyridine-3-yl)silane bidentate ligand (L) in a mixture of toluene and acetonitrile gives rise to purple crystals consisting of double-stranded ellipsoidal tubes, [Ni6(ClO4)4(CH3CN)8L12]·8ClO4·4CH3CN·5C7H8. The coordinated acetonitriles as well as the solvates are removed at 170 °C to transform the purple crystals into blue crystals of [Ni(ClO4)2L2]n that return to the original crystals in the mixture of toluene and acetonitrile. Further, the toluene and acetonitrile solvates of the original crystals are replaced by o-, m-, and p-xylene isomers within 5 min in a SCSC manner. In the present study, SCSC xylene-exchanged crystals were compared with crystals obtained from direct self-assembly in a mixture of each xylene isomer and acetonitrile

Host–Guest Chemistry of 1D Suprachannels and Dihalomethane Molecules: Metallacyclodimeric Ensembles Consisting of Zinc(II)-2,7-bis(nicotinoyloxy)naphthalene Complexes

Self-assembly of ZnX₂ (X = Cl, Br, and I) with 2,7-bis­(nicotinoyl­oxy)­naphthalene (L) as a hemicircular bidentate ligand containing a chromophore moiety yields a systematic metallacyclodimeric unit, [ZnX₂(L)]₂. These basic skeletons constitute, via interdigitated π···π interactions, a unique columnar ensemble forming a suprachannel. This can then be employed as an unusual “diiodomethane within the suprachannel” host–guest system, CH₂I₂@​[ZnX₂(L)]₂. Specifically, the suprachannel significantly stabilizes the CH₂I₂ molecules in the order [ZnI₂(L)]₂ > [ZnBr₂(L)]₂ > [ZnCl₂(L)]₂. This suprachannel has significant halogen effects on the photoluminescence (PL), thermal properties, and host–guest inclusion

Suprachannel as a Radical Trap: Crystal Structure of Single Carbon Radicals

We report proof-of-concept experiments on the unprecedented crystal structure of an iodomethyl radical (·CH₂I) nestled within an ensemble’s suprachannel via single crystal-to-single crystal photoreaction without destruction of the suprachannel. The trapped nonconjugated carbon radical was additionally confirmed by EPR, ¹³C MAS, UPS, and Raman spectra

Host–Guest Conversion: Transformation of Diiodomethane within 1D-Ensemble Suprachannels into Triiodide–Iodine Channel via Photoreaction

Self-assembly of ZnBr₂ with 2,7-bis­(isonicotinoyloxy)­naphthalene (L) yields one-dimensional (1D) zigzag chains of [ZnBr₂L] composition. This 1D chain ensemble forms unique suprachannels of 4.0 × 4.2 Ų size via weak C–H···π and π···π interactions. A 350 nm ultraviolet irradiation affects host–guest conversion. Diiodomethane molecules within the suprachannel structure of CHCl₃·CH₂I₂@[ZnBr₂L] were transformed into an unprecedented triiodide–iodine channel skeleton, HL⁺@[I₃·I₂]⁻. Specifically, two clear, quasi-reversible redox peaks were observed at +0.33 and +0.70 V versus Ag/AgCl in the anodic scan and at +0.19 and +0.62 V in the cathodic scan in acetonitrile for HL⁺@[I₃·I₂]⁻