Syntheses and crystal structures ofαmethyl alaninium dihydrogen monophosphate and Lβmethyl alaninium dihydrogen monophosphate. An approach for the design and preparation of polar organic-inorganic materials

The two following salts have been prepared [(CH 3 ) 2 C(NH 3 )-COOH] + · H 2 PO 4 − ( α MADP) and [CH 3 CH 2 CH(NH 3 )COOH] + · H 2 PO 4 − (L β MADP). The crystal parameters are: a = 10.060(2), b = 7.634(2), c = 5.852(2) Å, α = 97.32°(5), β = 107.50°(5), γ = 81.16°(5); Z = 2; P [unk] for α MADP and a = 7.164(2), b = 6.533(2), c = 9.458(2) Å; β = 105.48°(7); Z = 2; P 2 1 for L β MADP. Crystal structures were solved by direct methods and refined to a final R value 0.026 with 2889 independent data for α MADP and to R = 0.033 with 2027 reflexions for L β MADP. Hydrogen atoms located by difference-Fourier syntheses were refined. The layer structure of α MADP and the chain structure of L β MADP emphasize the importance of H 2 PO 4 − polymeric anion and its possible use in the design of polar inorganic materials. The effect of chirality on the anion-aggregation, through the hydrogen bonds, clearly indicated by the L β MADP structure and some others already described, may be easily transposed to individual, cylic, chain or layer inorganic oxoanions.