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A series of Ca-based coordination polymers were prepared mechanochemically by milling Ca(OH)2 with phthalic acid (H2oBDC), isophthalic acid (H2mBDC), and terephthalic acid (H2pBDC). The hydrated compounds [Ca(oBDC)(H2O)], [Ca(mBDC)(H2O)3.4], and [Ca(pBDC)(H2O)3] were prepared for the first time via mechanochemical routes. The refined structures were validated by extended X-ray absorption data. The new dehydrated compound [Ca(oBDC)] (1-H2O), obtained after the thermal post-treatment of 1 in a reversible phase transition process, was determined ab initio based on the powder X-ray diffraction (PXRD) data. The materials were thoroughly characterized using elemental analysis, thermal analysis, and spectroscopic methods: magic-angle spinning NMR and attenuated total reflection-infrared spectroscopy. The specific surface areas and sorption properties of the hydrated and dehydrated samples were determined using the isotherms of gas sorption and dynamic vapor sorption measurements.
Ca-, Sr-, and Ba-Based coordination polymers (CPs) were prepared mechanochemically by milling metal-hydroxide samples with anthranilic acid (oABAH). {[Ca(oABA)2(H2O)3]}n consists of one-dimensional polymeric chains that are further connected by a hydrogen-bonding network. {[Sr(oABA)2(H2O)2]·H2O}n is a one-dimensional CP in which water molecules bridge Sr2+ ions and increase the dimensionality by building an extended network. {[Ba(oABA)2(H2O)]}n crystallizes as a two-dimensional CP comprising one bridging water molecule. The cation radii influence the inorganic connectivity and dimensionality of the resulting crystal structures. The crystal structures were refined from powder X-ray diffraction data using the Rietveld method. The local coordination environments were studied via extended X-ray absorption fine structure (EXAFS) measurements. The compounds were further characterized using comprehensive analytical methods such as elemental analysis, thermal analysis, MAS NMR, imaging, and dynamic vapor sorption (DVS) measurements. Compounds 1, 2, and 3 exhibit small surface areas which decrease further after thermal annealing experiments. All compounds exhibit a phase transformation upon heating, which is only reversible in 3.