HYDROGEN-BONDING .56. IR-SPECTRA AND STOICHIOMETRY OF THE HYDRATES OFN-METHYLTRIETHYLENEDIAMINE CATION HALIDES AND HYDROXIDE

We have prepared the N-methyltriethylenediamine cation bromide hemihyd rate, chloride monohydrate, fluoride monohydrate and hydroxide dihydra te. These salts show no propensity to form higher crystalline hydrates . There is no indication of H2O to cage nitrogen hydrogen bonding, as was previously observed for the iodide monohydrate. Combination of IR and thermodynamic information demonstrates that the bromide and iodide hemihydrates have the same water-halide structure. Since the bromide hemihydrate does not contain (H2O.Br-)2 clusters, we conclude that the iodide hemihydrate does not contain (H2O.I-)2 clusters, as previously postulated. Both the bromide and iodide hemihydrates are presumed to contain C2v X-...HOH...X- groupings. The chloride and fluoride monohyd rates contain planar (H2O.X-)2 clusters. The hydroxide monohydrate cou ld not be prepared; the dihydrate decomposes slowly on further dehydra tion, presumably by S(N)2 attack of OH- on the methyl group.