183W NMR Studies of Tungstate Complexes of Carbohydrates. 2.Competitive Formation of erythro and threo Complexes of Alditols. Characterization of a Novel Bis-Dinuclear Complex Formed with Perseitol

Use of polyols as particle size and shape controllers: application to boehmite synthesis from sol–gel routes

“…[26][27][28][29][30] Both the number of hydroxyl groups, which is related to the carbon chain length, and the polyol stereochemistry were shown to be key parameters. Indeed, polyols complexing strength has been extensively studied.…”

“…Indeed, polyols complexing strength has been extensively studied. [26][27][28][29][30] Both the number of hydroxyl groups, which is related to the carbon chain length, and the polyol stereochemistry were shown to be key parameters. The positive impact on complexing strength of an increasing number of hydroxyl groups is rather obvious at first glance, as a cooperative effect of adjacent OH groups may be expected in the complexation phenomenon.…”

Aqueous Ethylenediamine Dihydroxo Palladium(II): A Coordinating Agent for Low- and High-Molecular Weight Carbohydrates

“…13 C NMR spectra of 1 and of the glucose part of 3 exhibit deshielding of the alkoxo carbon atoms by about Dd 10 ppm, which has also been observed for bis-ethylene- diamine-1,2-diolatocobalt(iii) compounds [24a] and in sugar alcohol complexes of molybdenum and tungsten. [28] In contrast, the chemical shifts of 2 and of the fructose part of 3 seem to contradict the commonly accepted assumption that a carbohydrate carbon atom bearing a metal-bound oxygen atom can be recognized by a CIS of 10 ppm or more. [28] However, a CIS of 10 ppm at, for example, a d 0 molybdenum(vi) centre may be of different origin than the same shift caused by a low-spin d 8 palladium(ii) center.…”

“…[28] In contrast, the chemical shifts of 2 and of the fructose part of 3 seem to contradict the commonly accepted assumption that a carbohydrate carbon atom bearing a metal-bound oxygen atom can be recognized by a CIS of 10 ppm or more. [28] However, a CIS of 10 ppm at, for example, a d 0 molybdenum(vi) centre may be of different origin than the same shift caused by a low-spin d 8 palladium(ii) center. Accordingly, the shifts reported here were not predicted exclusively from inductive effects.…”

Aqueous Ethylenediamine Dihydroxo Palladium(II): A Coordinating Agent for Low- and High-Molecular Weight Carbohydrates

“…Coordinationinduced shift is a well-known feature of the 13 C NMR spectra of polyolato complexes of molybdenum and tungsten. [28] In contrast, no CIS is observed for 2; the 13 C NMR chemical shifts of C2 and C4 are essentially the same as those of free levoglucosan. The 13 C NMR spectrum of 3 is characteristic of 1,2-and 1,3-diolate complexation.…”