Shi ZQ, Ji NN, Hu HL. A new Zn
II metallocryptand with unprecedented diflexure helix induced by V-shaped diimidazole building blocks.
ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2020;
76:411-416. [PMID:
32831259 DOI:
10.1107/s2052520620004217]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 03/27/2020] [Indexed: 06/11/2023]
Abstract
Taking advantage of V-shaped ligands, a ZnII metallocryptand, namely {[Zn2(didp)2(m-bdc)2]}n, (1) [didp = 2,8-di(1H-imidazol-1-yl)-dibenzothiophene and m-H2bdc = isophthalic acid], has been hydrothermally synthesized. Single-crystal X-ray diffraction analysis reveals a 26-membered butterfly-type metallomacrocycle [Zn2(didp)2]. One m-bdc2- ligand bridges [Zn2(didp)2] units to form a laterally non-symmetric [Zn2(didp)2(m-bdc)] metallocryptand with an exo-exo conformation. Another crystallographically independent m-bdc2- functions as a secondary synthon to bridge discrete metallocryptands into a 1D zigzag chain architecture. Undoubtedly, the choice of two matched ligands in this work is crucial for metallocryptand construction and structure expansion. Interestingly, a rare helical chain with two flexures in one single L and/or R strand is observed. Another important feature is the C-O...π interactions, by which the dimensionality extension of (1) can be induced. Fluorescence measurements and density functional theory (DFT) calculations illustrate that the emission of (1) can probably be attributed to ligand-to-ligand charge transfer (LLCT).
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