Inositols, borate complexes

Speculation is made about why epi-inositol flips into the triaxial form to form a tridentate complex with borate, but complexes without flipping with metal ions. The distances between the three axial oxygen atoms are similar to those between the three oxygen atoms in the ax-eq-ax sequence. However, in the triaxial borate complexes (3) the bonds are tetrahedral if one were formed at the ax-eq-ax oxygen atoms, the bonds would be considerably distorted. However, the angles have much less effect on complex formation with cations which does not involve covalent bonds. 

B-C bonds, 3, 97 B-N bonds, 3, 97 B-O bonds, 3,94 B-P bonds, 3, 97 B-Si bonds, 3, 97 oxo acid anion complexes, 3, 96 Borates, alkoxo-, 3, 94 Borates, amidotrihydro-, 3,92 Borates, aryloxo-, 3, 94 Borates, carboxylato-, 3,96 Borates, catechol, 3,95 Borates, chlorosulfato-, 3,97 Borates, dicarboxylato-, 3,96 Borates, dipyrazol-l-yl-, 3, 92 Borates, halogeno-, 3,92 Borates, halogenohydro-, 3,90 Borates, hydro-, 3,90 Borates, hydrohydroxo-, 3,90 Borates, hydropyrazol-l-yl-, 3, 92 Borates, hydroxo-, 3,94 Borates, hydroxycarboxylato-, 3,96 Borates, inositol, 3, 95 Borates, monoalkyl-, 3, 92 Borates, monophosphido-, 3, 92 Borates, peroxohydroxo-, 3, 94 Borates, polyol, 3, 95 Borates, pyrrol-l-yl-, 3, 92 Borates, sulfato-, 3, 97 Borates, tetrabromo-, 3, 92 Borates, tetrachloro-, 3, 92 Borates, tetrafluoro-, 3, 92 minerals, 6, 847 Borates, tetrahalogeno-mixed, 3, 93 nB NMR, 3, 92 Borates, tetraiodo-, 3, 92 Borates, tetranitrato-, 3, 96 Borates, tetraperchlorato-, 3, 97 Borates, tripyrazol-l-yl-, 3, 92 Borax, 3,101 Borazines... 

From the change of pH caused by successive additions of cyclitols to a borate solution, the equilibrium constants of complex formation have been calculated66 they show that the complexes are formed from cyclitol and borate in a 1 1 ratio. The stability of the tridentate borates depends on the steric disposition of the free hydroxyl groups in the complex the more of these in axial positions, the less stable the complex. This is illustrated by the values of the equilibrium constant in the following two series which are arranged by decreasing number of free axial hydroxyl groups in the complex scyWo-quercitol, 5.0 epf-quercitol, 310 m-quercitol, 7900 myoinositol, 25 epi-inositol, 700 and m-inositol, 1.1 X 106. When the constitution of a cyclitol allows the formation of both the tridentate and the classical, cis-1,2 type of complex, the former predominates. 

The structure of a rhenium(V) complex with l,3,5-trideoxy-l,3,5-tris (2-hydroxybenzylamino)-c /i -inositol has been described, and the metal ion sequestering abilities of borate esters of 2-amino-2-deoxy-D-gluconate and 2-amino-2-deoxy-D-galactonate have been studied. The largest effects were measured upon adding Cd(ll) or Ni(II) to the borate - 2-amino-2-deoxy-D-gluconate system. A ribonucleoside technetium chelate prepared from 2, 3 -diamino-2, 3 -dideoxyadenosine is mentioned in Chapter 20. 

Capillaiy zone electrophoresis (c.z.e.) separation of anions including carboxylates of sugar acids was achieved in a 3 minute run with indirect u.v. detection using a complex co-ion as an electroosmotic flow modifter that dynamically coats the capillary walls. " Inositol mono-, bis-, tris- and hexakis-phosphates were similarly separated using a tetradecylammonium bromide - borate buffer combination. Inositol 1- and 2-phosphate were easily separated." ... 

NMR spectroscopy has been used to determine the thermodynamics of borate ester formation by three readily grafted carbohydrates. Boron specia-tion in borate-poly(amido amine) dendrimer has been performed using B NMR spectroscopy. The role of inositol in the synthesis of FAU- and LTA-type zeolites has been investigated using H, C, Na, and Al NMR spectroscopy. Ulvan-boron complex formation has been studied using B and NMR spectroscopy. The complexation of borate ions and humic acid fractions has been analysed with B and H NMR spectroscopy. ... 

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