手性金属-有机骨架材料作为一种新型的多孔材料,在手性分离领域备受关注.以S-苹果酸和4,4'-联吡啶为配体与醋酸铜反应,通过溶剂热法合成了一种具有三维手性网状结构的手性金属-有机骨架材料[Cu(S-mal)(bpy)]n.将其用作固定相制成高效液相色谱手性柱,采用不同比例的正己烷/异丙醇作为流动相对一系列外消旋化合物进行手性拆分.结果显示,该手性柱对醇类、酮类、黄酮、酚类、胺类等17种外消旋化合物表现了较好的手性拆分能力.将该手性柱与之前我们报道的3种手性MOFs柱相比较,其表现出了更好的手性选择性,具有较好的手性拆分互补作用.最后还对该手性柱的重现性和稳定性做了评价,结果表明该手性柱表现出较好的重现性和稳定性.
Chiral metal-organic framework materials, as a new type of porous materials, have attracted much attention in the field of chiral separation. In this paper, a homochiral MOF [Cu(S-mal)(bpy)]n with 3D chiral networks was synthesized by the reaction of ligands (S-malic acid and 4,4'-bipyridine) with copper acetate via a solvothermal method. A packed chiral column for high performance liquid chromatography was fabricated using [Cu(S-mal)(bpy)]n as stationary phase. Before the packing, the MOF crystals was crushed in ethanol applying soft pressure and then the MOF with suitable particle size (5 - 10 μm) was obtained via solvent suspension. A 4.2 g mass of prepared MOF was suspended in a mixture of hexane and isopropanol. In order to control the packing quality, the suspension of MOF was packed into a stainless steel empty column (25 cm long × 4.6 mm i.d.) under 40 MPa using hexane/isopropanol (9 : 1, V/V) as the slurry solvent according to a conventional high pressure slurry packing procedure. To investigate the chiral recognition ability of this stationary phase, a series ofracemic compounds were separated on the chiral MOF columm using different ratio of n-hexane/isopropanol as mobile phase. The results showed that the chiral column exhibited good resolving ability towards 17 racemates, including alcohols, ketones, flavonoids, phenols and amines. For instance, the resolution value of 1-(1-naphthyl)ethanol could reach 4.5. Compared with three kinds of homochiral MOFs columns previously reported by our group, this column showed better chiral recognition ability and higher resolution toward racemates, and has a good complementary for chiral separation. The [Cu(S-mal)(bpy)]n possesses cavities with average dimensions (5 A° × 5 A° ×6 A°), which were interconnected by narrow windows with diameter ≤3 A°. Therefore, the chiral recognition mostly depends on the surface of the MOF crystal in which the steric fit between the chiral networks and conformation of the