Salts containing different amino acids: Salts with β-alaninium L-proline dimeric cation

Recently we have discovered a new class of amino acids salts containing different amino acids. In the present paper we report crystal structures of salts with the beta-alaninium L-proline dimeric cation: beta-alaninium L-proline chloride, (beta-AlaH center dot center dot center dot(L)-Pro)Cl (I), beta-alaninium L-proline bromide, (beta-AlaH center dot center dot center dot(L)-Pro)Br (II), beta-alaninium L-proline iodide, (beta-AlaH center dot center dot center dot(L)-Pro)I (III), beta-alaninium L-proline tetrafluoroborate, (beta AlaH center dot center dot center dot(L)-Pro)BF 4 (IV), beta-alaninium L-proline perchlorate, (beta-AlaH center dot center dot center dot(L)-Pro)ClO4 (V) and beta-alaninium Lproline nitrate, (beta-AlaH center dot center dot center dot l-Pro)NO3 (VI). The salts (I-III) are isostructural and crystallize in the polar space group P2(1) with one formula unit in the asymmetric unit. The salts (IV-VI) crystallize in space group P2(1)2(1)2(1) with two (isotypic compounds (IV) and (V)) resp. one (VI) formula units in the asymmetric unit. The O center dot center dot center dot O distances in the dimeric cations are 2.490(5) angstrom (I), 2.5001(19) angstrom (II), 2.529(3) angstrom (III) and 2.556(4), 2.581(4) angstrom (IV), 2.566(5), 2.570(5) angstrom (V) and 2.561(2) angstrom (VI). These values are compared with those in salts with dimeric cations (beta-AlaH center dot center dot center dot beta-Ala) and (l-ProH...l-Pro) with respective anions. Infrared spectra of obtained salts were registered and are discussed. (C) 2021ElsevierB.V. Allrightsreserved.

Automated summary

A new class of amino acid salts containing different amino acids has been discovered recently. In this study, crystal structures of salts with the beta-alaninium L-proline dimeric cation were reported. The salts exhibit varying O...O distances in the dimeric cations and were compared with other salts containing dimeric cations. Infrared spectra of the obtained salts were also analyzed and discussed.