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Complex formation of two calix[4]arene derivatives - containing two ethoxycarbonylmethoxy groups or a bridge including two carboxamide moieties in the coordination sphere - with aliphatic amines (n-octylamine, OA and triethylamine, TEA) were the subject of FT-IR studies. Two nitrophenyl type auxochromic moieties were also present in both of the ligands. Solvent effects were studied in chloroform, diiodomethane and dichloromethane. Presumably, in these reactions, the reactants undergo phenol-amine type interactions and, simultaneously, coordinative interaction takes place between the carbonyl group of the ligand and the protonated form of the aliphatic amine. Complex formation of calixarene 1a with n-octylamine was complete resulting in drastic changes in the FT-IR spectra. Moreover, the possibility of the formation of a new compound by the reaction between the ester type functionalities and octylamine was precluded. The expected ligand was synthesized and its spectra were compared with those of calixarene 1a. In most of the cases of calixarene 1b, the amide moiety of the carboxamide bridge does not participate in the complex formation with the exception of complexes formed in diiodomethane solution and of the 1b-TEA complex observed in dichloromethane.

The 'host' properties of distally dialkylated calix[4]arenes and 4-tert-butylcalix[4]arenes in the presence of 1-chloro-4-(trifluoromethyl)benzene (BFT) were studied in chloroform solvent by intensity-independent spectrofluorometric method. The anisotropy decay experiments were found as suitable method to indicate the host-guest complex formation but it is unable to determine the strength of supramolecular interaction.

Complexation of lithium ions by three chromoionophoric calix[4]arenes has been studied by ¹H and 7Li NMR spectroscopy. The signalling unit of the chromoionophores is the N-methylpyridinium(methyleneimino) group in conjugation with a phenolic group of the calixarene ring while the coordination spheres contain esteric (ethoxycarbonylmethoxy) or etheric (ethoxy, propoxy) units. ¹H NMR and NOESY measurements suggest the dominance of cone conformations of the calixarene rings with slight, solvent-dependent distortions. Complexation occurs only in the presence of a weak base. The interaction with lithium ions causes a broadening of both the ¹H and 7Li NMR signals. Analysis of the chemical shifts in the three complexes indicates a different coordination environment for the lithium with the calixarene containing esteric groups from those having etheric groups. This explains the differences in the stabilities of the lithium complexes of the two types of calixarenes. [ABSTRACT FROM AUTHOR]

The first representatives of 1,3-alt-thiacalix[4]arene bis(crown-5 and -6) ethers were synthesized by the cyclocondensation of thiacalix[4]arenes with tetraethylene glycol ditosylate and 1,14-diiodo-3,6,9,12-tetraoxatetradecane, respectively. The complexing abilities of ligands were determined by alkali (Na+, K+, Rb+, Cs+) picrate extraction methods. [Copyright &y& Elsevier]

The first representatives of 1,3-alt-thiacalix[4]mono(crown-5 and -6) ethers were synthesized by the cyclocondensation of 25,27-dialkoxythiacalix[4]arenes with tetraethylene glycol ditosylate and 1,14-diiodo-3,6,9,12-tetraoxatetradecane, respectively. The complexing abilities of ligands were determined by the alkali (Li+, Na+, K+, Rb+, Cs+) picrate extraction method. [Copyright &y& Elsevier]

The complexation behavior of the distally dialkylated calix[4]arenes and 4-tert-butylcalix[4]arenes (hosts) with 1-chloro-4-(trifluoromethyl)benzene (guest) was examined in four different alcohols (MeOH, EtOH, n-PrOH, n-BuOH) as solvents. The complex stability constants (Ks) and the complexation energy of the host–guest complexes were determined. Fair ‘by group’ linear correlations between each log K series determined in the same solvent and the complex stabilization energies were found. As a consequence, the solvents having high permittivities result in less stability of the host–guest complex in these particular cases examined. [Copyright &y& Elsevier]

A new spiropyran derivative containing a calixcrown ring has been synthesised. Thermal conversion from merocyanine to the spiropyran form was studied in ethanol and in acetonitrile, and equilibrium and kinetic data were compared with those of the parent 6-nitrospiropyran. The kinetics of thermal decay of the merocyanine form of the calixcrown-spiropyran molecule shows a biexponential character in both solvents, while the decay is much slower in ethanol than in acetonitrile. [Copyright &y& Elsevier]