Lulich Alice, Amiri Mehran, Stephen Doctor, Shohel Mohammad, Mao Zhiwei, Nyman May
Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States.
ACS Omega. 2023 Mar 6;8(11):10476-10486. doi: 10.1021/acsomega.3c00114. eCollection 2023 Mar 21.
Bismuth metal-organic frameworks and coordination polymers (CP) are challenging to synthesize, given the poor solubility of bismuth precursors and asymmetric and labile ligation of Bi due to its intrinsic lone pair. Here, we synthesize and structurally characterize three Bi-CPs, exploiting a tetrafluoroterephtalate (FBDC) linker to determine the effect of high acidity on these synthesis and coordination challenges. Single-crystal X-ray diffraction characterization showed that pi-pi stacking of linkers directs framework arrangement and generally deters open porosity in the three structures, respectively featuring Bi chains ( ), Bi dimers ( ) linked into chains, and Bi tetramers ( ). Powder X-ray diffraction and microscopic imaging show the high purity and stability of these compounds in water. Naphthalenedisulfonate (NDS) was used as a mineralizer in the synthesis of ( ) and ( ), and studies of its role in assembly pathways yielded two additional structures featuring mixed NDS and FBDC, respectively, linking monomer and octamer Bi nodes, and confirmed that FBDC is the preferred (less labile) linker. Methylene blue (MB) adsorption studies show differing efficacies of the three Bi-FBDC phases, attributed to surface characteristics of the preferential growth facets, while generally most effective adsorption is attributed to the hydrophobicity of fluorinated ligands. Finally, thermogravimetric analysis of all three Bi-FBDC phases indicates simultaneous ligand degradation and in situ formation of volatile Bi compounds, which could be exploited in the chemical vapor deposition of Bi-containing thin films.
铋金属有机框架和配位聚合物（CP）的合成具有挑战性，因为铋前驱体的溶解性差，且由于铋的固有孤对电子，其配位不对称且不稳定。在此，我们合成并对三种铋配位聚合物进行了结构表征，利用四氟对苯二甲酸酯（FBDC）连接体来确定高酸度对这些合成和配位挑战的影响。单晶X射线衍射表征表明，连接体的π-π堆积引导框架排列，并且通常会阻碍三种结构中的开放孔隙率，这三种结构分别具有铋链（ ）、连接成链的铋二聚体（ ）和铋四聚体（ ）。粉末X射线衍射和显微镜成像表明这些化合物在水中具有高纯度和稳定性。萘二磺酸盐（NDS）在（ ）和（ ）的合成中用作矿化剂，对其在组装途径中的作用的研究产生了另外两种结构，分别具有混合的NDS和FBDC，连接单体和八聚体铋节点，并证实FBDC是更优选的（较不稳定的）连接体。亚甲基蓝（MB）吸附研究表明三种铋-FBDC相具有不同的吸附效率，这归因于优先生长面的表面特性，而一般来说最有效的吸附归因于氟化配体的疏水性。最后，对所有三种铋-FBDC相的热重分析表明配体同时降解并原位形成挥发性铋化合物，这可用于含铋薄膜的化学气相沉积。
