TY - JOUR

T1 - New hydrophobic l-amino acid salts

T2 - Maleates of l-leucine, l-isoleucine and l-norvaline

AU - Arkhipov, Sergey G.

AU - Rychkov, Denis A.

AU - Pugachev, Alexey M.

AU - Boldyreva, Elena V.

PY - 2015/7/1

Y1 - 2015/7/1

N2 - Crystals of maleates of three amino acids with hydrophobic side chains [l-leucenium hydrogen maleate, C6H14NO2 +.C4H3O4 -, (I), l-isoleucenium hydrogen maleate hemihydrate, C6H14NO2 +.C4H3O4 -.0.5H2O, (II), and l-norvalinium hydrogen maleate-l-norvaline (1/1), C5H11NO2 +.C4H3O4 -.C5H12NO2, (III)], were obtained. The new structures contain C22(12) chains, or variants thereof, that are a common feature in the crystal structures of amino acid maleates. The l-leucenium salt is remarkable due to a large number of symmetrically non-equivalent units (Z′ = 3). The l-isoleucenium salt is a hydrate despite the fact that l-isoleucine is a nonpolar hydrophobic amino acid (previously known amino acid maleates formed hydrates only with lysine and histidine, which are polar and hydrophilic). The l-norvalinium salt provides the first example where the dimeric cation l-Nva⋯l-NvaH+ was observed. All three compounds have layered noncentrosymmetric structures. Preliminary tests have shown the presence of the second harmonic generation (SGH) effect for all three compounds.

AB - Crystals of maleates of three amino acids with hydrophobic side chains [l-leucenium hydrogen maleate, C6H14NO2 +.C4H3O4 -, (I), l-isoleucenium hydrogen maleate hemihydrate, C6H14NO2 +.C4H3O4 -.0.5H2O, (II), and l-norvalinium hydrogen maleate-l-norvaline (1/1), C5H11NO2 +.C4H3O4 -.C5H12NO2, (III)], were obtained. The new structures contain C22(12) chains, or variants thereof, that are a common feature in the crystal structures of amino acid maleates. The l-leucenium salt is remarkable due to a large number of symmetrically non-equivalent units (Z′ = 3). The l-isoleucenium salt is a hydrate despite the fact that l-isoleucine is a nonpolar hydrophobic amino acid (previously known amino acid maleates formed hydrates only with lysine and histidine, which are polar and hydrophilic). The l-norvalinium salt provides the first example where the dimeric cation l-Nva⋯l-NvaH+ was observed. All three compounds have layered noncentrosymmetric structures. Preliminary tests have shown the presence of the second harmonic generation (SGH) effect for all three compounds.

KW - crystal structure

KW - L-amino acids

KW - l-isoleucine

KW - l-leucine

KW - l-norvaline

KW - l-norvaline-l-norvalinium dimer

KW - maleate

KW - noncentrosymmetric layered structures

KW - SHG effect

UR - http://www.scopus.com/inward/record.url?scp=84937417916&partnerID=8YFLogxK

U2 - 10.1107/S2053229615010888

DO - 10.1107/S2053229615010888

M3 - Article

C2 - 26146397

AN - SCOPUS:84937417916

VL - 71

SP - 584

EP - 592

JO - Acta Crystallographica Section C: Structural Chemistry

JF - Acta Crystallographica Section C: Structural Chemistry

SN - 2053-2296

ER -