The synthesis and characterization of new oligo(polyether)s with Schiff base type

New oligo(polyether) ligands with Schiff base type were synthesized by the reaction of diethyleneglycol bis(2-aminophenyl ether) and triethyleneglycol bis(4-aminophenyl ether) with oligosalicylaldehyde (OSA). OSA was synthesized from the oxidative polycondensation of salicylaldehyde (SA) with air in an aqueous alkaline medium at 90 °C. The products were characterized by 1H-NMR, 13C-NMR, FT-IR, UV–Vis and elemental analysis. The number average molecular weight, Mn, mass average molecular weight, Mw, and polydispersity index values, PDI, of OSA, graft oligo[1,5-di(N-2-oxyphenyl-salicylidene)-3-oxapentane] (compound 4) and graft oligo[1,8-di(N-4-oxyphenyl-salicylidene)-3,6-oxaoctane] (compound 5) were found to be 1690 g mol−1, 5150 g mol−1, 3.05, 1100 g mol−1, 5400 g mol−1, 4.90 and 1100 g mol−1, 5600 g mol−1, 5.01, respectively. TG and DTA analyses were shown to be stable of oligo(polyether) ligands with Schiff base type against thermo-oxidative decomposition. The weight loss of oligo(polyether) ligands with Schiff base type (compounds 4 and 5) were found to be 52 and 56% at 1000 °C, respectively.