DFT/B3LYP Study of Thermochemistry of D-Glucosamine, a Representative Polyfunctional Bioorganic Compound

D-glucosamine, as a representative polyfunctional compound, is a bioactive amino sugar. inthis study, the gas phase thermochemical properties of d-glucosamine, including its metal ionaffinity (mia), metal binding sites, anion affinity (aa), acidity and proton affinity, have beenexplored, using the density functional theory (oft) and a 6-311++g**basis set. the summaryof the mia and aa results (in kcal/rnolt ) are: li^+= 67.6, na^+= 51.1, k^+= 37.3, mg^2+=207.9, ca^2+= 150.4, zn^2+= 251.2, (cl^--= 27.4, cn^-= 28.0. the acidity values calculatedat different sites, including four -oh groups and one -nh z group, range from 344.0 to 373.0kcal/mol- 1. these results, surprisingly, indicate how drastically the presence of multiple -oh and-nh z groups may vary the thermochemical properties of a polyfunctional bioorganic compound,such as d-glucosamine