Synthesis and Characterization of Hydrazide-Linked and Amide-Linked Organic Polymers

Four kinds of either hydrazide-linked or amide-linked polymers were facilely synthesized by using hydrazine, tetrakis(4-aminophenyl)methane (TAPM), terephthaloyl chloride (TPC), and trimesoyl chloride (TMC) as building blocks. The morphology, porosity, composition, and surface property of polymers were characterized by scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption measurement, ¹³C/CP-MAS NMR, X-ray photoelectron spectroscopy, etc. The results indicated that building blocks had important effects on morphology and porosity. Poly(TMC-TAPM) synthesized with TMC and TAPM showed the highest surface area of 241.9 m² g^-1. In addition, note that a hollow structure with ∼20 nm wall thickness was formed in poly(TMC-hydrazine) prepared with TMC and hydrazine. Further study indicated that both carboxyl groups (-COOH) and hydrazide groups (-CONH-NH₂) existed on the surface of poly(TMC-hydrazine), besides the mainly hydrazide linkage (-CONH-NHOC-). Taking advantages of good hydrophilicity and special functional groups on the surface, we finally adopted poly(TMC-hydrazine) to enrich glycopeptides from tryptic digest via both hydrophilic interaction chromatography method with identification of 369 unique N-glycosylation sites and hydrazide chemistry method with identification of 88 unique N-glycosylation sites, respectively.