Poly[μ3-β-alanine-aqua-μ4-sulfato-dilithium]

The title compound, [Li2(SO4)(C3H7NO2)(H2O)]n, is a coordination polymer in which the β-alanine residues remain in the zwitterionic form. The crystal structure consists of corrugated sheets of [LiO4] and [SO4] tetrahedra parallel to (010) with the β-alanine molecules located between the sheets. The two independent Li+ cations are four-coordinated by O atoms in a distorted tetrahedral geometry. The crystal structure is formed by stacking of alternate organic and inorganic layers along the a axis. The crystal structure is further stabilized by N—H⋯O hydrogen bonds.

The title compound, [Li 2 (SO 4 )(C 3 H 7 NO 2 )(H 2 O)] n , is a coordination polymer in which the -alanine residues remain in the zwitterionic form. The crystal structure consists of corrugated sheets of [LiO 4 ] and [SO 4 ] tetrahedra parallel to (010) with the -alanine molecules located between the sheets. The two independent Li + cations are four-coordinated by O atoms in a distorted tetrahedral geometry. The crystal structure is formed by stacking of alternate organic and inorganic layers along the a axis. The crystal structure is further stabilized by N-HÁ Á ÁO hydrogen bonds.

Comment
Naturally available β-alanine is constituent of the dipeptides, carnosine and anserine. It has the ability to form coordinate complexes with different metals both transition and nontransition elements due to its free carboxylate anion in its zwitterionic form. Previous reports have shown that β-alanine was forming crystalline complexes with organic and inorganic compounds (Liao et al., 2001;Urpí et al., 2003;Pestov et al., 2005;Anbuchezhiyan et al., 2010).
Herein, we are reporting a very interesting crystal structure of β-alanine with lithium sulfate. Both β-alanine and lithium got tremendous interest to chemists due to their importance in medicine and pharmaceuticals (Poolsup et al., 2000;Cipriani et al., 2005;Anderson et al., 2008;Tiedje et al., 2010). Recently β-alanine is gaining momentum as a sports medicine (Derave et al., 2007) and Lithium remains as the 'gold standard' drug as mood stabiliser suitable for bipolar disorder (Geddes et al.,2 004). Hence the study of the title compound, which is formed by the combination of two potential drugs viz. β-alanine and lithium sulfate, will be very much useful for drug design and identification of the material.
The asymmetric unit ( Fig.1) contains one-half of the compound, the other half being related to the first by an inversion centre. The structure of the title compound ( Fig.2 supplementary materials sup-2 N, 6.48%; S, 12.4%. The close agreement between the calculated and observed values shows that the molecules of β-alanine, lithium sulfate and water have combined in equimolar ratio to form the title compound. From TGA we observed a weight loss of 8% between 166°C and 193°C which shows the presence of water molecules in the equimolar ratio in the title compound.

Refinement
The water H atoms were located in a difference Fourier, and refined isotropically with O-H restraints (0.86 (2) Å). All other H atoms were positioned geometrically (C-H = 0.96-0.97 Å; N-H = 0.91 Å) and in the refinement process were allowed to ride on their carrier atoms with Uiso(H) = 1.2Ueq(C, N). Fig. 1. The asymmetric unit of the title compound, with atom labels and anisotropic displacement ellipsoids drawn at the 50% probability level. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq S −0.30781 (7)