Henkelis Susan E, Huber Dale L, Vogel Dayton J, Rimsza Jessica M, Nenoff Tina M
Nanoscale Sciences Department, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States.
Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States.
ACS Appl Mater Interfaces. 2020 Apr 29;12(17):19504-19510. doi: 10.1021/acsami.0c01813. Epub 2020 Apr 14.
The magnetic susceptibility of NO-loaded RE-DOBDC (rare earth (RE): Y, Eu, Tb, Yb; DOBDC: 2,5-dihydroxyterephthalic acid) metal-organic frameworks (MOFs) is unique to the MOF metal center. RE-DOBDC samples were synthesized, activated, and subsequently exposed to humid NO. Each NO-loaded MOF was characterized by powder X-ray diffraction, and the magnetic characteristics were probed by using a VersaLab vibrating sample magnetometer (VSM). Lanthanide-containing RE-DOBDC (Eu, Tb, Yb) are paramagnetic with a reduction in paramagnetism upon adsorption of NO. Y-DOBDC has a diamagnetic moment with a slight reduction upon adsorption of NO. The magnetic susceptibility of the MOF is determined by the magnetism imparted by the framework metal center. The electronic population of orbitals contributes to determining the extent of magnetism and change with NO (electron acceptor) adsorption. Eu-DOBDC results in the largest mass magnetization change upon adsorption of NO due to more available unpaired f electrons. Experimental changes in magnetic moment were supported by density functional theory (DFT) simulations of NO adsorbed in lanthanide Eu-DOBDC and transition metal Y-DOBDC MOFs.
负载一氧化氮的稀土-二羟基对苯二甲酸金属有机框架材料（RE-DOBDC，稀土（RE）：钇、铕、铽、镱；二羟基对苯二甲酸：2,5-二羟基对苯二甲酸）的磁化率对于金属有机框架材料的金属中心而言是独一无二的。合成、活化了RE-DOBDC样品，随后将其暴露于潮湿的一氧化氮中。通过粉末X射线衍射对每个负载一氧化氮的金属有机框架材料进行了表征，并使用VersaLab振动样品磁强计（VSM）探测了其磁特性。含镧系元素的RE-DOBDC（铕、铽、镱）具有顺磁性，吸附一氧化氮后顺磁性降低。Y-DOBDC具有抗磁矩，吸附一氧化氮后略有降低。金属有机框架材料的磁化率由框架金属中心赋予的磁性决定。轨道的电子填充情况有助于确定磁性的程度以及吸附一氧化氮（电子受体）后磁性的变化。由于有更多未成对的f电子，Eu-DOBDC在吸附一氧化氮后导致最大的质量磁化率变化。通过对吸附在镧系元素Eu-DOBDC和过渡金属Y-DOBDC金属有机框架材料中的一氧化氮进行密度泛函理论（DFT）模拟，支持了磁矩的实验变化。
