Conformational aspects of meso-tartaric acid. XI. Structure of lithium hydrogen meso-tartrate monohydrate

Abstract

oxygen atoms 02 and 03 respectively (Table 2d). This is in contrast to the structure of arginyl-glutamic acid which shows specific H-bonding interactions between the guanidyl group and carboxyl oxygen atoms of the glutamic acid side chain (Pandit, Seshadri & Viswamitra, 1983). Fig. 2 and Table 2(d) show that the two water molecules in the asymmetric unit form independent water chains along b. These chains are also H-bonded to the L-arginyl-L-aspartic acid residues.We thank Dr T. P. Seshadri for his help during data collection and DST and DBT for financial support.References Enraf-Nonius (1979 (2), c = 5.3107 (4)A, fl=95.768 (5) °, V= 654.71 (7) A 3, Z =4, Dx=l.766gcm -3, 2(MoKa)=0.71073A, g =1.6cm -x, F(000)=360, T=294K, R=0.042, wR=0.048 for 2326 observed reflections with I > 2.5tr(I). The crystal structure is a racemate of two conformational antipodes of the meso-tartrate anion, which has adopted its usual gauche conformation with respect to the carbon chain. The glycolic acid parts are almost planar. The Li ÷ ion is irregularly coordinated to five O atoms at a mean distance of 2.05 (6) tl,.Introduction. The crystal structure determination of the title compound is part of the research program which is being carried out on the molecular conformational aspects of neutral meso-tartaric acid and its ionized forms. A second point of interest is the nature of hydr0gen-bond schemes inacid salts in general.

Crystal structure of 1,2,3,4-tetrahydroisoquinolin-2-ium (2S,3S)-3-carboxy-2,3-dihydroxypropanoate monohydrate

“…In the vast majority of these crystal structures, the carbon skeleton of the hydrogen tartrate anion exhibits the anti conformation. Exceptions are the crystal structure of quininium (S,S)-hydrogen tartrate hemihydrate (PUVTUV; Ryttersgaard & Larsen, 1998), lithium meso-hydrogen tartrate monohydrate (COFGAF10; Stouten et al, 1988), potassium meso-hydrogen tartrate monohydrate (KHMTAR01; Currie et al, 1975) and 1-(4 0 -cyano-4 0 -cyclohexyl-4 0 -phenylbutyl)piperidinium (S,S)-hydrogen tartrate (EZOWUL; Jones, 2004) in which the hydrogen tartrate anions are found in the gauche conformation.…”