Influence of the CO···π Interaction on the Thermal Dehydration Behavior of [Cu₂(sgly)₂(H₂O)]·1H₂O^†

The hydrogen-bonding pattern present in [Cu2(sgly)2(H2O)]·H2O [1; H2sgly = N-(2-hydroxybenzyl)glycine] has been found to be very similar to that observed in [Cu2(sala)2(H2O)] (2), which undergoes solid state transformation from a hydrogen-bonded one-dimensional helical coordination polymeric structure to a three-dimensional (3D) coordination polymeric network structure with chiral channels, after losing all of the water molecules below 110 °C. However, 1 fails to undergo such a transformation when dehydrated thermally. Furthermore, the intermolecular hydrogen bonds in 1 are weaker than those found in 2. A detailed crystal structure analysis of 1 reveals that the presence of the CO···π intermolecular interaction between a carboxylate carbonyl group and a phenyl ring appears to be responsible for the weakening of hydrogen bonds, thermal dehydration behavior, preventing the formation of new Cu−O bonds and, hence, the 3D coordination polymeric network structure.