Synthesis and Structural Characterization of Lithium-Based Metal−Organic Frameworks

Two lithium-based metal−organic frameworks, Li2(C14H8O4) [Li2(4,4′-BPDC) [1]; ULMOF-2, UL = ultralight; BPDC = biphenyldicarboxylate]; space group P21/c, a = 12.758(2) Å, b = 5.142(4) Å, c = 8.00(2) Å, β = 97.23°, V = 520.6(14) Å3 and Li2(C14H8O6S) [Li2(4,4′-SDB) [2]; ULMOF-3, UL = ultralight; SDB = sulfonyldibenzoate], space group P21/n, a = 5.5480(11) Å, b = 23.450(5) Å, c = 10.320(2) Å, β = 96.47(3)°, V = 1334.1(5) Å3, were synthesized. Compounds 1 and 2 were synthesized by solvothermal methods and were characterized using single crystal X-ray diffraction. Structure 1 consists of layers of two-dimensional antifluorite related LiO motif connected by BPDC linkers, whereas structure 2 is constructed by a combination of tetrameric lithium polyhedral clusters connected by the sulfonyldibenzoate linker. The frameworks are stable up to 575 and 500 °C, respectively, under N2 atmosphere.

本研究合成了两种锂基金属有机框架：其一为Li₂(C₁₄H₈O₄)[Li₂(4,4′-BPDC) [1]; ULMOF-2，其中UL代表超轻质（ultralight, UL），BPDC代表联苯二甲酸盐（biphenyldicarboxylate, BPDC）]，其空间群为P2₁/c，晶胞参数为a=12.758(2) Å，b=5.142(4) Å，c=8.00(2) Å，β=97.23°，晶胞体积V=520.6(14) ų；其二为Li₂(C₁₄H₈O₆S)[Li₂(4,4′-SDB) [2]; ULMOF-3，其中UL代表超轻质（ultralight, UL），SDB代表二苯砜二甲酸盐（sulfonyldibenzoate, SDB）]，其空间群为P2₁/n，晶胞参数为a=5.5480(11) Å，b=23.450(5) Å，c=10.320(2) Å，β=96.47(3)°，晶胞体积V=1334.1(5) ų。化合物1与化合物2均通过溶剂热法合成，并采用单晶X射线衍射进行结构表征。其中，化合物1的结构由二维反萤石型LiO结构基元构成的层状骨架通过BPDC桥联配体连接而成；而化合物2则由四聚体锂多面体簇通过二苯砜二甲酸盐桥联配体组装得到。上述两种框架材料在氮气氛围下分别可稳定至575 ℃与500 ℃。