High-resolution nuclear magnetic resonance spectroscopy studies of polysaccharides crosslinked by sodium trimetaphosphate: a proposal for the reaction mechanism

• Published in: Carbohydrate research Vol. 342; no. 7; pp. 943 - 953
• Main Authors: Lack, Stéphane, Dulong, Virginie, Picton, Luc, Cerf, Didier Le, Condamine, Eric
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 21.05.2007; Elsevier
• Subjects: 31P Nuclear magnetic resonance spectroscopy; Chemical Sciences; Cross-Linking Reagents - analysis; Cross-Linking Reagents - chemistry; Crosslinking mechanism; Glucans - chemistry; Hydrogels; Hydrogels - chemical synthesis; Hydrogels - chemistry; Hydrogen-Ion Concentration; Magnetic Resonance Spectroscopy - methods; Molecular Structure; Polymers; Polyphosphates - analysis; Polyphosphates - chemistry; Polysaccharides - analysis; Polysaccharides - chemistry; Pullulan; Sodium trimetaphosphate; dd; Hydrogels; STPP; NaPF 6; τ c; heteroCOSY; ADP; COSY; PO(OMe) 3; Int; STPP g; P c; Glc-OMe; P g; pH; P i; Crosslinking mechanism; PP g; STMP; Pullulan; AMP; d; T 1; DSS; T 2; PP i; ppm; m; Sodium trimetaphosphate; aq; at; s; t; ND; HR-MAS NMR; 31P Nuclear magnetic resonance spectroscopy; ATP
• ISSN: 0008-6215; 1873-426X; 0008-6215
• DOI: 10.1016/j.carres.2007.01.011

Reaction between methyl α- d-glucopyranoside and sodium trimetaphosphate (STMP) in alkaline medium was studied by nuclear magnetic resonance spectroscopy ( 31P, 1H, 13C). We have determined the various formed species and the reaction mechanism. An NMR spectroscopy study ( 31P, 1H, 13C) of the postulated crosslinking mechanism of sodium trimetaphosphate (STMP) on polysaccharides is reported using methyl α- d-glucopyranoside as a model. In a first step, reaction of STMP with Glc-OMe gives grafted sodium tripolyphosphate (STPP g). On the one hand, STTP g can react with a second alcohol functionality to give a crosslinked monophosphate. On the other hand, a monophosphate (grafted phosphate) could be obtained by alkaline degradation of STPP g. NMR spectroscopy allows to detect the various species formed and to obtain the crosslinking density of STMP–polysaccharides hydrogels.