Manganese complexes hydroxycarboxylates

The oxalate [Mn(C204)3], like the catecholate [Mn(cat)3] compounds, can be readily oxidized to Mn state. Otherwise, oxalate can form polymers and the combination of phosphate and oxalate in fomting hybrid framework materials has been also explored. Several hydroxycarboxylates exist as monomers or polymers and the first mononuclear manganese citrate complex, (NH4)4[Mn(C6H507)2], has been recently isolated and crystallographically characterized. ... 

Cartoni et al. [88] studied perspective of the use as stationary phases of n-nonyl- -diketonates of metals such as beryllium (m.p. 53°C), aluminium (m.p. 40°C), nickel (m.p. 48°C) and zinc (liquid at room temperature). These stationary phases show selective retention of alcohols. The retention increases from tertiary to primary alcohols. Alcohols are retained strongly on the beryllium and zinc chelates, but the greatest retention occurs on the nickel chelate. The high retention is due to the fact that the alcohols produce complexes with jS-diketonates of the above metals. Similar results were obtained with the use of di-2-ethylhexyl phosphates with zirconium, cobalt and thorium as stationary phases [89]. 6i et al. [153] used optically active copper(II) complexes as stationary phases for the separation of a-hydroxycarboxylic acid ester enantiomers. Schurig and Weber [158] used manganese(ll)—bis (3-heptafiuorobutyryl-li -camphorate) as a selective stationary phase for the resolution of racemic cycUc ethers by complexation GC. Picker and Sievers [157] proposed lanthanide metal chelates as selective complexing sorbents for GC. Suspensions of complexes in the liquid phase can also be used as stationary phases. Pecsok and Vary [90], for example, showed that suspensions of metal phthalocyanines (e.g., of iron) in a silicone fluid are able to react with volatile ligands. They were used for the separation of hexane-cyclohexane-pentanone and pentane-water-methanol mixtures. 

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