NHN+ AND NHN- HYDROGEN-BONDS IN THE ADDUCTS OF 1,8-BIS(DIMETHYLAMINO)NAPHTHALENE WITH 1,8-BIS(TRIFLUOROACETAMIDO)NAPHTHALENE AND 1,8-BIS(4-TOLUENESULPHONAMIDO)-2,4,5,7-TETRANITRONAPHTHALENE

The crystal structure of the adduct of 1,8-bis(dimethylamino)napthalene (DMAN) with 1,8-bis(trifluoroacetamido)-naphthalene (TFAN) was determined from X-ray diffraction studies. The crystal of DMAN . TFAN are monoclinic, space group C2/c, with a = 20.181(4), b = 17.068(4), c = 18.333(4) angstrom, beta = 122.64(4)-degrees and Z = 8. The NHN- hydrogen bond formed after the abstraction of the proton from TFAN is 2.608(4) angstrom long with [NHN equal to 138(3)degrees. Remarkable symmetrization of the anion takes place although the bridge H-atom is localized closer to one nitrogen atom. H-1 NMR and IR studies in acetonitrile show that the ion pairs formed in the systems DMAN-TFAN and DMAN-TSATNN (1,8-bis(4-toluenesulphonamido)-2,4,5,7-tetranitronaphthalene) are very stable and that the NHN- hydrogen bonds in DMAN . TFAN are slightly stronger than those in DMAN . TSATNN.