School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
ISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX, UK.
Nat Commun. 2017 Feb 13;8:14212. doi: 10.1038/ncomms14212.
Hydrogen bonds dominate many chemical and biological processes, and chemical modification enables control and modulation of host-guest systems. Here we report a targeted modification of hydrogen bonding and its effect on guest binding in redox-active materials. MFM-300(V) {[V(OH)(L)], LH=biphenyl-3,3',5,5'-tetracarboxylic acid} can be oxidized to isostructural MFM-300(V), [VO(L)], in which deprotonation of the bridging hydroxyl groups occurs. MFM-300(V) shows the second highest CO uptake capacity in metal-organic framework materials at 298 K and 1 bar (6.0 mmol g) and involves hydrogen bonding between the OH group of the host and the O-donor of CO, which binds in an end-on manner, =1.863(1) Å. In contrast, CO-loaded MFM-300(V) shows CO bound side-on to the oxy group and sandwiched between two phenyl groups involving a unique ···c.g. interaction [3.069(2), 3.146(3) Å]. The macroscopic packing of CO in the pores is directly influenced by these primary binding sites.
氢键在许多化学和生物过程中起主导作用，而化学修饰则能够实现对主体-客体体系的控制和调节。在这里，我们报告了对氢键的靶向修饰及其对氧化还原活性材料中客体结合的影响。MFM-300(V) {[V(OH)(L)]，LH=联苯-3,3',5,5'-四羧酸}可以被氧化为结构相同的 MFM-300(V)，[VO(L)]，其中桥连羟基发生去质子化。MFM-300(V)在 298 K 和 1 巴（6.0 mmol g）下显示出金属-有机骨架材料中第二高的 CO 吸收容量（6.0 mmol g），涉及主体中 OH 基团和 CO 的 O-供体之间的氢键，其结合方式为端到端，=1.863(1)Å。相比之下，负载 CO 的 MFM-300(V)显示 CO 以侧接方式与氧基结合，并被两个苯环夹在中间，涉及独特的···c.g.相互作用[3.069(2)，3.146(3)Å]。CO 在孔中的宏观堆积直接受到这些主要结合位点的影响。
