As a monolayer version of nanoscale metal organic frameworks (nMOFs), nanoscale metal–organic layers (nMOLs) have recently emerged as a novel class of two-dimensional (2D) molecular nanomaterials. nMOLs are built from metal-oxo secondary building units (SBUs) with suitable coordination modes and organic linkers with proper geometries in a bottom-up fashion by carefully controlling the reaction temperature, capping agents, water concentration, and other parameters. M₆-BTB and related nMOLs are formed by linking M₆(μ₃-O)₄(μ₃-OH)₄ (M = Zr⁴⁺, Hf⁴⁺, Ce⁴⁺) SBUs and planar tricarboxylate bridging ligands such as 1,3,5-benzene-tribenzoate (BTB), while M₁₂-nMOLs are constructed from M₁₂(μ₃-O)₈(μ₃-OH)₈ (μ₂-OH)₆ (M = Zr⁴⁺, Hf⁴⁺) SBUs and linear dicarboxylate ligands such as 5,15-di(p-benzoato)porphyrin (DBP). Mechanistic studies revealed the important roles of capping agents and water on the growth of nMOLs and the stepwise growth process involving the partial hydrolysis of metal ions to form metal-oxo clusters with capping agents and the subsequent replacement of capping agents by bridging ligands. The 2D nature of nMOLs facilitates the postsynthetic modification of bridging ligands and the exchange of capping agents to simultaneously incorporate multifunctionalities into nMOLs.

中文翻译：

---

用于生物医学应用的纳米级金属有机层

作为纳米级金属有机框架 (nMOFs) 的单层版本，纳米级金属有机层 (nMOLs) 最近已成为一类新型的二维 (2D) 分子纳米材料。nMOL 由具有合适配位模式的金属-氧代二级构建单元 (SBU) 和具有适当几何形状的有机连接器以自下而上的方式通过仔细控制反应温度、封端剂、水浓度和其他参数构建而成。M ₆ -BTB 和相关的 nMOL 通过连接 M ₆ (μ ₃ -O) ₄ (μ ₃ -OH) ₄ (M = Zr ⁴⁺ , Hf ⁴⁺ , Ce ⁴⁺) SBU 和平面三羧酸桥接配体如 1,3,5-苯三苯甲酸酯(BTB)，而 M ₁₂ -nMOLs 由 M ₁₂ (μ ₃ -O) ₈ (μ ₃ -OH) ₈ (μ ₂ - OH) ₆ (M = Zr ⁴⁺ , Hf ⁴⁺ ) SBUs 和线性二羧酸配体如 5,15-di( p-苯并）卟啉（DBP）。机理研究揭示了封端剂和水对 nMOL 生长的重要作用，以及金属离子部分水解形成金属氧簇与封端剂以及随后由桥连配体替代封端剂的逐步生长过程。nMOLs 的二维性质促进了桥接配体的合成后修饰和封端剂的交换，以同时将多功能性纳入 nMOLs。