Chiral Supramolecular Microporous Thio-Oxomolybdenum(V) Tartrates for the Selective Adsorptions of Gases.

Abstract

Two pairs of enantiomerically pure hexanuclear and tetranuclear microporous molybdenum(V) d/l-tartrates, (H2trz)3[Mo6O6(μ2-O)3(μ2-S)3(d/l-Htart)3(Htrz)6]·8H2O (abbreviated as d-1 and l-1; H4tart = tartaric acid, Htrz = 1,2,4-triazole) and (H22-mim)8[Mo4O4(μ2-S)4(d/l-tart)2]2·4H2O (d-2/l-2; H2-mim = 2-methylimidazole), have been isolated in reduced media and well characterized. These enantiomers are observed to finish self-assemblies with single chiral configurations. Structural analyses indicate that tartrates adopt different coordination modes with α-carboxy and/or α-alkoxy groups in 1 and 2, which are further completed with nitrogen-containing ligands. There are two types of micropores that exist in 1 and 2, separately, which are all formed by the isolated molecules themselves. The significant roles of hydrogen bonding among lattice molecules, tartrates, and multi-azoles are suggested, where 1 and 2 exhibited interesting supramolecular networks only through intramolecular self-sorts. Adsorption tests show that 1 has good affinities toward CO2 and O2, while 2 is the most potential O2 adsorbent compared with other common gases CO2, H2, CH4, and N2 under different pressures. In addition, IR, UV-vis, CD (circular dichroism), and solid-state 13C NMR spectroscopies have demonstrated the special chemical properties of these novel molybdenum d/l-tartrates.