Structures of tetrapotassium, tetrarubidium and tetracaesium 1,4,5,8-naphthalenetetracarboxylate hexahydrates

Abstract

(Fitzgerald, Gallucci & Gerkin, 1991b). Of particular interest in this series is the effect of cation size on crystal structure and the attendant hydrogenbonding network, as well as on the conformation of the organic anion. Heretofore, no structural series for simple Group IA salts of an aromatic carboxylic acid has been reported. Structures of aromatic acid salts have been reported, and these are compared to the structures of the tetranaphthalate salts. Moreover, there have been few reports of hydrated aromatic salts in which the H atoms have been located and refined successfully. The present study, therefore, was also planned to add appreciably to the structural data available for hydrated aromatic salts. AbstractThe three title salts are isomorphic except for one structural feature. Each of the two water molecules of the tetrapotassium structure has one H atom disordered over two sites in a cyclic hydrogen-bond arrangement. Disordered H atoms appear not to be present in the tetrarubidium and tetracaesium structures. The effect of cation size on the geometry of the organic anion in these solids is most readily observed in the configuration and conformation of the carboxylate groups. The four unique C--O bond lengths, and the four unique C--C--O bond angles, of the carboxylate groups exhibit more than one value and in a consistent manner among the three structures.

Polymer-Induced Self-Assembly of Small Organic Molecules into Ultralong Microbelts with Electronic Conductivity

“…The carboxylate groups are torsioned from the perylene ring systemsee Figure S2 and Table S4. These deviations of the planes of the carboxylate groups with respect to the mean plane of the perylene core are similar to those in potassium naphthalene-1,4,5,8-tetracarboxylate . The C−O bond lengths of the carboxylate groups range from 1.252(2) to 1.267(2) Å (Table S2).…”

Structures of artificial sweeteners – cyclamic acid and sodium cyclamate with other cyclamates

“…There is no covalent interaction between the layers, which are separated from each other by the hydrophobic cyclohexane parts -protruding from both sides. It is interesting to note that the sodium, potassium, rubidium and ammonium cylamates are isostructural: because of the smaller size of the Na + cation, the sodium salt does not normally fit into such a series, as exemplified by alkali hydrogen acetylenedicarboxylates [Na + (Leban, 1974a); K + (Leban et al, 1973); Rb + (Blain et al, 1973); NH þ 4 (Leban, 1974b)] and alkali naphthalenetetracarboxylates (Fitzgerald et al, 1993).…”

Room-Temperature FTIR Spectra of the Cyclic S4 (H2O)4 Cluster in Crystalline Li2(H2O)4(B12F12): Observation of B and E ν(OH) Bands and Coupling of Strong O–H···O and Weak O–H···F Vibrations

“…Its FTIR spectrum also has a broad and uninformative ν­(OH) region, as shown in Figure S10 . There are other examples of R4 clusters in crystalline compounds, including several in which the H 2 O molecules are coordinated to alkali metals. − However, none of these papers reported vibrational spectra that can be interpreted unambiguously.…”