Synthesis, physicochemical and pharmacokinetic characterization of calcium uronates

Atypical calcium coordination number: Physicochemical study, cytotoxicity, DFT calculations and in silico pharmacokinetic characteristics of calcium caffeates

“…This confirms that the water molecule is weakly bound to the calcium ion in these complexes [29][30][31], in accordance with theoretical calculations, suggesting its place in the second coordination sphere. Two stage water decomposition can be a consequence of their different interaction with the ligand molecules via a net of hydrogen bonding.…”

“…These bands are indicative of coordination of the carboxylic group of caffeic acid [10,13]. The most important bands related to the metal-oxygen vibration were found in 290-500 cm À1 region [29]. The intensive band characteristic of the calcium-oxygen (COO À ) vibration was found at 414 cm À1 and calculated at 416 cm À1 .…”

“…This hydrogen bond causes a tilt of the Ca-O(H 2 O) bond, by about 20°, from an axial position (the angles O14-Ca-O12 and O14-Ca-O13 0 are 66.0°and 107.7°, respectively). Generally, releasing of the water molecules from the first coordination sphere (CN5 and 6) takes place at the temperature above 140°C [29,30]. In this case two water molecules are removed below this temperature.…”

“…The binding mode of water molecules may have an important consequence in e.g. pharmacokinetics [29].…”

Interaction of hydantoins with transition metal ions: synthesis, structural, spectroscopic, thermal and magnetic properties of [M(H2O)4(phenytoinate)2] M = Ni(II), Co(II)

“…This observation is supported by the enthalpy changes while complete dehydratation and loss of coordination water in the complex (2) ( Table 6). The temperature range for releasing of the first water molecule is 60-100°C with a week endothermic effect (DH = 6.7 kJ/mol, Table 7) characteristic for the dehydratation process [31] and corresponding to a loss of a crystalline water molecule (stage I). On heating from 100 to 140°C, the mass loss of 3.70% was observed, corresponding to a loss of one and half ammonia molecule (Table 6, stage II).…”