Proton-transfer and non-transfer in compounds of quinoline and quinaldic acid with L-tartaric acid

Abstract

The structures of two compounds of l-tartaric acid with quinoline, viz. the proton-transfer compound quinolinium hydrogen (2R,3R)-tartrate monohydrate, C9H8N+·C4H5O6−·H2O, (I), and the anhydrous non-proton-transfer adduct with quinaldic acid, bis­(quinolinium-2-carboxyl­ate) (2R,3R)-tar­taric acid, 2C10H7NO2·C4H6O6, (II), have been determined at 130 K. Compound (I) has a three-dimensional honeycomb substructure formed from head-to-tail hydrogen-bonded hydrogen tartrate anions and water mol­ecules. The stacks of π-bonded quinolinium cations are accommodated within the channels and are hydrogen bonded to it peripherally. Compound (II) has a two-dimensional network structure based on pseudo-centrosymmetric head-to-tail hydrogen-bonded cyclic dimers comprising zwitterionic quinaldic acid species which are inter­linked by tartaric acid mol­ecules.