Hydrothermal Synthesis and Characterization of a Metal–Organic Framework by Thermogravimetric Analysis, Powder X-ray Diffraction, and Infrared Spectroscopy: An Integrative Inorganic Chemistry Experiment

Abstract

This advanced undergraduate laboratory experiment involves the synthesis and characterization of a metal−organic framework with microporous channels that are held intact via hydrogen bonding of the coordinated water molecules. The hydrothermal synthesis of Co 3 (BTC) 2 •12H 2 O (BTC = 1,3,5-benzene tricarboxylic acid) is carried out using one of four different reactors (stainless steel, microwave, polypropylene bottle, or sealed glass ampules) and the products are evaluated and compared using thermogravimetric analysis, powder X-ray diffraction, and IR spectroscopy. Powder X-ray diffraction is also used to monitor the changes in structure of the framework during the partial or complete removal of the associated water molecules, as well as after reabsorption of water.

Water-Driven Structural Transformation in Cobalt Trimesate Metal-Organic Frameworks

“…All the patterns reported in Figure 1a,b were equivalent, and they were all different from the patterns reported for other metal trimesates. The structures used for the comparison were obtained by search in articles collection databases [24,[35][36][37][38][39][40][41][42][43][44][45][46]48,[51][52][53][54] and in the Cambridge Structural Database (CCSD, [55]) using as a query in ConQuest one cobalt atom bound to one oxygen atom of a BTC linker and coordinated to two additional oxygen atoms through a single bond. The most intense reflection of the pattern was centered at 10.2 • , corresponding with a d-spacing of 8.7 Å.…”

“…These reflections could not be indexed as belonging to the expected products from KCL-102 decomposition (Co(OH) 2 , Co 3 O 4 , and trimesic acid) or to any other reported Co trimesates (Refs. [35][36][37][38][39][40][41][42][43][44][45][46]). Although these peaks could be related to an additional Co trimesate phase, we suggest that they were associated with the formation of mesopores due to framework collapse, as already reported for other MOFs.…”

“…The first material reported as a metal-organic framework by Yaghi et al in 1995 was a cobalt trimesate [36]. Other cobalt trimesates were reported since then for very different applications [37][38][39][40][41][42][43][44][45]. Among them, Co 3 (BTC) [46] is particularly interesting for energy related applications.…”

MOFs (METAL-ORGANIC FRAMEWORKS): UMA FASCINANTE CLASSE DE MATERIAIS INORGÂNICOS POROSOS

“…Com relação a este último tópico, os principais grupos de pesquisa em MOFs têm usado predominantemente a dinâmica molecular clássica para estudar os tipos de interação com moléculas gasosas, embora alguns estudos utilizando a simulação de estrutura eletrônica baseada na Teoria do Funcional da Densidade (DFT) também estão sendo realizados. 3,8 Do ponto de vista do ensino de Química, periódicos como o Journal of Chemical Education vêm demonstrando a importância da realização de experimentos sobre o tema MOFs em disciplinas de Química Inorgânica, 14,15 já estando inclusive na capa de um importante livro-texto de Química Geral. 16 No que diz respeito à material de referência sobre o assunto disponível em língua portuguesa, do que seja do nosso conhecimento, existem apenas dois artigos publicados na Química Nova 17,18 e um livro coordenado pelo professor Severino Alves, da Universidade Federal de Pernambuco.…”

Synthesis and Characterization of POMs-Based Coordination Polymer: A Comprehensive Chemical Experiment

“…配位聚合物是由配位方式多样的金属离子或金属簇与有机配体通过配位键(或者超分子作用)连 接而形成的具有一维、二维或三维结构的聚合物，因其独特的结构以及其在吸附、脱附上的潜在应 用前景受到人们的广泛关注 [1] 。多酸(Polyoxometalates，简写为 POMs)是一类具有大量的表面端氧和 桥氧原子、可控的形状和尺寸、高负电荷以及其他多种性质的阴离子金属氧簇，这使得多酸可以作 为次级结构单元(Secondary Building Units，简写为 SBUs)来构筑结构新颖的功能性多酸配位聚合 物 [2,3] 。 从 1826 年发现第一个杂多酸金属盐，1864 年合成出第一个杂多酸--12-钨硅酸，多酸化学发 展至今已有接近两个世纪的悠久历史。而"12-钨硅酸的制备和性质"作为我校化学专业综合化学实 验中"功能材料及特殊合成技术"专题的重要组成实验之一，可以让学生了解多酸化学这一重要领 域，一直深受学生的好评 [4] 。近年来，多酸化学与配位化学领域逐渐交叉融合，使得多酸配位聚合物 的合成和性质研究逐渐成为无机化学和材料化学领域的重要研究方向之一，但在校大学生接触这类 材料的机会并不多 [5] 。与多酸配位聚合物相关的知识除了无机化学教学内容中配位化学等相关知识 外，还涉及有机化学中有机配体合成、分析化学和物理化学中相关表征以及性能分析等知识体系。 所以，如果能在大学化学实验中引入多酸配位聚合物的制备与表征，不仅能使学生对已经学习的知 识体系融会贯通，还有利于减小本科教学与实际科研之间的差距，提升学生学习化学的兴趣 [6][7][8] [9]…”