Actinide complexes phenols

In hydrogenation, early transition-metal catalysts are mainly based on metallocene complexes, and particularly the Group IV metallocenes. Nonetheless, Group III, lanthanide and even actinide complexes as well as later metals (Groups V-VII) have also been used. The active species can be stabilized by other bulky ligands such as those derived from 2,6-disubstituted phenols (aryl-oxy) or silica (siloxy) (vide infra). Moreover, the catalytic activity of these systems is not limited to the hydrogenation of alkenes, but can be used for the hydrogenation of aromatics, alkynes and imines. These systems have also been developed very successfully into their enantioselective versions. 

C14H22O, Phenol, 2,6-di-tert-butyl-, actinide and lanthanide complexes, 27 166... 

The actinide cations can form strong complexes with humic and fulvic acid ligands. This may reflect the presence of phenolic, amine, and alcoholic OH-groups, and also carbonate groups in... 

C 4H gOgP, 1/7-Phospholium, 2,3,4,5-tetra-kis(methoxycarbonyl)-2,2-dimethyl-, manganese complex, 26 167 C,4H2QOgPS. 2W-l,2-Thiaphosphorin-2-ium, 3,4,5,6-tetrakis(methoxycaibonyl)-2,2-dimethyl-, manganese complex 26 165 C,4H720, Phenol, 2,6-di-terr-butyl-, actinide and lanthanide complexes, 27 166 C HjjP, Phosphine, di-rm-butylphenyl-, palladium and platinum complexes, 28 114, 116... 

OC14H22, Phenol, 2,6-di-KrT-butyl- actinide and lanthanide complexes, 27 166 OC15H24, Phenol, 2,6-di-reiT-butyl-4-methyl-, actinide and lanthanide complexes, 27 166... 

The calix[4]arene molecule was modified at both the upper (para) and lower (phenolic) rims by the introduction of phosphate and phosphonate groups, mainly by the group of Kalchenko (Fig. 4B). Such derivatives complex and allow the extraction of lanthanide and actinide tri- and tetravalent cations. Detoxification of radioactive waters may be possible in this way, as the chemieal and physical robustness of the calix[n]arenes makes them particularly suitable for this task. 

The parent oxacalix[3] arenas show little ability to bind alkali metals,however, a range of quaternary ammonium cations are attracted to the symmetric cavity. Deprotonation of the phenol moieties allows them to bind to transition metals (scandium, titanium, vanadium, rhodium, molybdenum, gold, etc.), lanthanides (lutetium. yttrium, and lanthanum), and actinides (uranium as uranyl). Oxacalix[3]arenes derivatized on the lower rim can complex gallium, mercury, and alkali metals, including sodium, in a manner reminiscent of natural transmembrane cation filters. One major use was to purify crude samples of fullerenes. The pseudo-Cs symmetry of the macrocyclic cavity is complementary to threefold symmetry elements of Cgo. which binds preferentially in... 

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