Studies Directed to Understanding the Structure of Chitosan−Metal Complexes:  Investigations of Mono- and Disaccharide Models with Platinum(II) Group Metals

Abstract

X-ray and NMR experiments were performed with simple chitosan models based on glucosamine monosaccharides and disaccharides to understand the binding properties and structures of the complexes formed between this polysaccharide and platinum(II) metals. Subjection of the glucosamine derivatives with [PdCl2(PhCN)2] provided trans-diamine complexes which upon further treatment with excess (NH4)PF6 generated complexes possessing two 5-membered chelate rings involving the C2-amine and the C3-hydroxyl group of the two individual glucosamine units.

Oxovanadium(IV) complexes of carbohydrates: A brief overview

“…The N-donors may be provided by the same chitosan chain, as reported in the case of the Fe(III) complex [28], or by two parallel opposing chains, generating a trans-diamine arrangement, similar to that proposed for the Pd(II) complex [24,29].…”

Modeling the coordination chemistry of chitosan: Synthesis and characterization of a nickel(II) complex with a 2-aminoglucose Schiff-base ligand

“…Due to its versatility, biocompatibility, insolubility and non-toxicity chitosan is of current interest as support and supramolecular ligand for heterogeneous catalysis [2][3][4][5][6][7][8][9]. Schiff-base modified derivatives of chitosan show good catalytic activities concerning cyclopropanation, alkane oxidation and C-C coupling reactions [10][11][12][13].…”

Highly Enantioselective Transfer Hydrogenation of Prochiral Ketones Using Ru(II)‐Chitosan Catalyst in Aqueous Media

“…The major, broad, unresolved set of signals (5.60, 5.41, 2.64 ppm) showed formation of a flexible complex with the p ‐cym in its composition (signals corresponding to the two CH 3 groups showed similar pattern). We assigned these signals to H of complexes in which amino groups are coordinated to the Ru, based on previously proposed interaction of aminosaccharide derivatives with Pd . The well‐resolved signal set (5.24, 5.03, 2.53 ppm) may be attributed to formation of a more rigid half‐sandwich type complex in which a glucosamine monomer may act as a bidentate ligand and is coordinated to the metal by two amino groups or by the involvement of hydroxyl and/or acetamido groups ,.…”

“…We assigned these signals to H of complexes in which amino groups are coordinated to the Ru, based on previously proposed interaction of aminosaccharide derivatives with Pd . The well‐resolved signal set (5.24, 5.03, 2.53 ppm) may be attributed to formation of a more rigid half‐sandwich type complex in which a glucosamine monomer may act as a bidentate ligand and is coordinated to the metal by two amino groups or by the involvement of hydroxyl and/or acetamido groups ,. Due to the overlapped signals it is not possible to identify certainly the ring Hs, however, one may observe the split of the H2 signal in two signals.…”