VERY STRONG HYDROGEN-BONDS IN HYDRATED 1/1 ADDUCTS OF AN OLEFINIC DOUBLE BETAINE WITH PERCHLORIC AND NITRIC-ACIDS - L.HCLO4.H2O AND L.HNO3.H2O [L=CIS-(P-ME2N+C5H4N)2C2(COO-)2]

The hydrated 1:1 adducts of an olefinic double betaine with perchloric and nitric acids, L.HClO4.H2O 1 and L.HNO3.N2O 2 [L = cis-(p-Me2N+C5H4N)2C2(COO-)2], have been shown to be nearly isostructural by X-ray crystallography and infrared spectroscopy. The common cationic unit HL+ of both compounds exhibits significant semi-quinonoid character and possesses symmetry m, its two coplanar carboxylate groups being linked by a very strong, nearly linear intramolecular O-H-O hydrogen bond [O...O 2.397(9) angstrom and O-H-O 167.1-degrees for 1; 2.388(7) angstrom and 167.4-degrees for 2]. The HL+ units are further connected by intermolecular O-H...O hydrogen bonds between the exocyclic carboxyl oxygen atoms and the water molecules to generate polymeric zigzag chains running parallel to the c axis, and the disordered ClO4- or NO3- anions occupy channels running parallel to the a axis in the resulting host lattice.