Sudarath deravong. Synthesis of 25,27-[N,N-DI-((ethoxy)benzyl)propylenediamine]-26,28-dimethoxy-p-tert-butylcalix[4]arene dihydrochloride and investigation of its basicity and complexation with some transition metal ions. Master's Degree(Chemistry). Chulalongkorn University. Center of Academic Resources. : Chulalongkorn University, 1998.
Synthesis of 25,27-[N,N-DI-((ethoxy)benzyl)propylenediamine]-26,28-dimethoxy-p-tert-butylcalix[4]arene dihydrochloride and investigation of its basicity and complexation with some transition metal ions
Abstract:
25,27-[N,N-di-((ethoxy)benzyl)propylenediamine]-26,28-dimethoxy-p-tert-butylcalix[4]arene dihydrochloride (7, L.2HCl), an ammonium derivative of diaza calix[4]arene, was prepared by methylating phenoxy oxygen of dialdehyde calix[4]arene with CH3I. The methylated dialdehyde was then reacted with 1,3-diaminopropane to give a schiff base compound which was then reduced with NaBH4 and protonated with 2% HCl in CH3OH. The conformational isomerism of L.2HCl was studied by 1H NMR spectroscopy. 1H NMR spectra of L.2HCl in CDCl3 and in DMSO-d6 showed that the calix[4]arene moiety orientated in mixed conformations. However, the 1H NMR spectrum in CD3OD indicated cone conformation. Gradual additions of CD3OD into a CDCl3 solution of L.2HCl revealed that intermolecular hydrogen bonding between methanol and CH3OAr-t-C4H9 held the calix[4]arene framework incone conformation. Variable temperature experiments of L.2HCl in a mixed solvent of CD3OD/CDCl3 implied a possible mechanism of phenyl ring movement and suggested that a pinched cone conformation was preferred at -40 ํC. In addition, protonation constants of L were calculated in methanolic solution of 1 x 10-2 M Bu4NCF3SO3 by potentiometric titration. Log K1(Log K2) values of the first protonation (second protonation) were 10.06 (6.67), 9.97 (6.75), 9.61 (6.64), 9.75 (6.77) and 9.69 (6.68) at 20, 23, 25, 27 and 30 ํC, respectively. Calculated thermodynamic functions, triangleH1, triangleH2, triangleS1 and triangleS2 for the first and second protonations were -67 kJ/mol, 3 kJ/mol, -38 kJ/mol K and 137 kJ/mol K, respectively. Complexation studies of L with Zn2+ and Cu2+ ions by the same method showed that L could not form complexes with both ions.