The structural chemistry of lithium, sodium and potassium anthranilate hydrates

Abstract

Lithium, sodium and potassium anthranilates (2-aminobenzoates) have been prepared by neutralization of anthranilic acid with the corresponding alkali hydroxides in aqueous solution. Li(Anth) and Na(Anth) crystallize as hemihydrates, K(Anth) as the monohydrate. A single crystal structure determination has shown that Li(Anth)-(H 2 O) 0.5 forms a chain structure composed of unique polyhedral compartments with ten-membered ring rims sharing two opposite rectangular faces. The strings are connected via hydrogen bonds involving the amino groups which are not part of the inner coordination sphere of the penta-coordinated lithium atoms. By contrast, Na(Anth)(H 2 O) 0.5 has a layer structure with the hexa-and hepta-coordinated sodium atoms O,N-chelated by anthranilate anions and interconnected via bridging carboxylate groups and water molecules. Hydrogen bonding contributes to the connectivity within a given sheet with its corrugated double-layer of sodium atoms, but not beyond the layers which are shielded by the arene rings. K(Anth)(H 2 O) also forms a sheet structure with a single corrugated layer of sevencoordinated potassium cations O,O-chelated and bridged by the anthranilate anions and by the water molecules. The amino groups have no contact with the metal centres and are involved solely in hydrogen bonding. The hydrocarbon rings extending above and below the sheets show no π-π-stacking and are not indented. DALTON

Conformational Preferences of N,N-Dimethylsuccinamate as a Function of Alkali and Alkaline Earth Metal Salts: Experimental Studies in DMSO and Water As Determined by 1H NMR Spectroscopy

“…Distances of carboxylate-metal ion complex in the respective gauche conformers for 1a – 1c were calculated to be greater than their trans counterparts in each case. For example, the calculated Li + –O distances for 1a (1.93–1.96 Å) in the gauche conformer are consistent with the values of 1.90–2.67 Å found in lithium-carboxylate X-ray crystal structures, 16−18 while the values of 1.84–1.85 Å observed in the trans conformer appear to be slightly underestimated. The calculated Na + –O distances (2.26–2.29 Å) in gauche 1b and the K + –O distance in gauche 1c (2.58–2.70 Å) matched the values observed in crystal structures (i.e., 2.26–2.67 Å and 2.36–2.73 Å, respectively), 19−22 whereas the values in the trans conformers are slightly lower (i.e., 2.19–2.20 Å for 1b and 2.53–2.54 Å for 1c ).…”

Interactions of a β-dipeptide with monovalent metal cations: crystal structures of (anthranoyl)anthranilic acid and its lithium, sodium and thallium salts☆

“…Structural investigations have been performed on the anthranilates of the alkali [35,36] and earth alkaline metals [37,38] as well as of several first row transition metals [39,40] and of thallium [41,42]. The consideration of the thallium(I) cation in this series served to illustrate its specific coordination characteristics (especially as opposed to the potassium cation which has almost the same size) which may be one of the main reasons for the toxicity of this group 13A metal [43].…”

Synthesis, spectroscopy, thermal studies and supramolecular structures of two new alkali-earth 4-nitrobenzoate complexes containing coordinated imidazole

“…In this context, a rich structural chemistry of the biologically relevant alkali and alkali-earth metals has been recently developed with amino as well as mercapto benzoic acids. [9][10][11][12][13][14][15] As part of an ongoing programme, we are investigating the chemistry of metal complexes of 4-nitrobenzoic acid (4-nbaH) to exploit the H-bonding capabilities of the nitro functionality. [16][17][18] The versatile ligational behaviour of the 4-nitrobenzoate (4-nba) ligand is well documented in the literature.…”