Antiferromagnetic Copper(II) Metal–Organic Framework Based Quartz Crystal Microbalance Sensor for Humidity

Abstract

A novel copper metal–organic framework (MOF) [Cu3L2(H2O)2.75]·0.75H2O·1.75DMA (H3L = 4-(2-carboxyphenoxy)-isophthalic acid, DMA = dimethylacetamide) has been synthesized and structurally characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction. Compound 1 shows a three-dimensional architecture with a sqc topology net where the [Cu2(COO)4] unit was viewed as a node. Magnetic studies indicate that strong antiferromagnetic coupling with J = −159.0(9) cm–1 dominates in the compound. As a sensor, the compound based on quartz crystal microbalance (QCM) exhibits good linearity humidity sensing properties after being exposed to various relative humidity environments at room temperature. The resulting sensitivity is about 28.7 Hz/%RH with a good linearity coefficient of 0.993.