Intermolecular non-covalent interactions in the organic perrhenates crystal structures: from theory to practice†

Ten novel perrhenates of nitrogenous heterocycles have been generated throughout this investigation. The crystal structure of these compounds was thoroughly examined, and intermolecular non-covalent interactions were analysed using the Hirshfeld surface approach. Organic perrhenate cations interact primarily through intermolecular contacts of the H⋯H, O⋯H/H⋯O, and N⋯H/H⋯N types, whereas anions interact mostly via O⋯H/H⋯O interactions. Six of the eight structures with aromatic fragments had anion–π interactions, whereas four of the 11 structures had anion–anion interactions of the Re–O type. Previously unexplored subtypes of 2D networks composed of interacting tetrahedral perrhenate anions have been discovered in piperazinium and triazolium salts. Thermochemical analysis suggests that Re–O⋯Re anion–anion interactions provide additional stabilisation and impact phase transitions in perrhenates. The consistent patterns of organic salt perrhenate behaviour under MALDI-spectrometry settings have been identified. Characteristic multiplets for rhenium acid salts, which can be designated MALDI fingerprints, have been found. Potential formulae of oxorhenates corresponding to the listed multiplets have been specified.