Sodium 3-(2-Chlorophenyl)propenoate Dihydrate and Tetraaquamagnesium Bis[3-(2-hydroxyphenyl)propenoate]

Poly[μ5-{hydrogen bis-[(E)-cinnamato]}-caesium]

In the structure of the title polymeric complex, [Cs(C₉H₇O₂)(C₉H₈O₂)]_n, a caesium salt of trans-cinnamic acid, the Cs⁺ ions of the two individual irregular CsO₈ coordination polyhedra lie on twofold rotation axes and are linked by four bridging carboxyl O-atom donors from two cinnamate ligand species. These two ligand components are inter­linked through a delocalized H atom within a short O⋯H⋯O hydrogen bond. Structure extension gives a two-dimensional coordination polymer which lies parallel to (001). The structure was determined from a crystal twinned by non-merohedry, with a twin component ratio of approximately 1:1.

Anhydrous thallium hydrogen L-glutamate: polymer networks formed by sandwich layers of oxygen-coordinated thallium ions cores shielded by hydrogen L-glutamate counterions

Anhydrous thallium hydrogen L-glutamate [Tl(L-GluH)] crystallizes from water (space group P2(1)) with a layer structure in which the thallium ions are penta- and hexacoordinated exclusively by the oxygen atoms of the γ-carboxylate group of the hydrogen L-glutamate anions to form a two-dimensional coordination polymer. The thallium-oxygen layer is composed of Tl(2)O(2) and TlCO(2) quadrangles and is only 3 Å high. Only one hemisphere of the thallium ions participates in coordination, indicative of the presence of the 6s(2) lone pair of electrons. The thallium-oxygen assemblies are shielded by the hydrogen l-glutamate anions. Only the carbon atom of the α-carboxylate group deviates from the plane spanned by the thallium ions, the γ-carboxylate groups and the proton bearing carbon atoms, which are in trans conformation. Given the abundance of L-glutamic and L-aspartic acid in biological systems on the one hand and the high toxicity of thallium on the other hand, it is worth mentioning that the dominant structural motifs in the crystal structure of [Tl(L-GluH)] strongly resemble their corresponding analogues in the crystalline phase of [K(L-AspH)(H(2)O)(2)].