Porphyrin thorium

The actinide element, thorium, also forms a porphyrin complex, ThIV(Por)(acac)2, in the same way as the lanthanide derivatives (Scheme 8).l7a The acetylacetonato groups most likely coordinate to the thorium atom on the same side of the porphyrin (Scheme 8). Thlv and Ulv(OEP)Cl2L2 (L = PhCN, THF, py) are prepared from H2(OEP) and MC14.35... 

The first accurate description of the optical properties of homoleptic tetrapyrrole sandwiches relies on a TDDFT study of zirconium(IV), ceri-um(IV) and thorium(IV) bis(porphyrins) [136]. 

Finally porphyrins and phthalocyanins can give sandwich type compounds such as UIV(porph)2, UIV(Pc)2, and [UnI(porph)2]. 32 Thorium gives similar complexes. 

Large metal ions such as thorium or uranium were also employed in order to combine a porphyrin, octaethylporphyrin (OEP), with a phthalocyanine (Pc) chromophore in face-to-face or double-decker orientation. and Th compounds could be electrogenerated in up to seven different oxidation states. The first two reductions occurred mainly on the Pc ring while the first two oxidations of the same heteroleptic compounds involved primarily orbitals of the porphyrin macrocycle. In contrast, the homoleptic (MP)2 and (MPc)2 derivatives undergo initial one-electron oxidations and reductions which are localized not at a single ring, but involve both macrocycles. ... 

Porphyrin complexes of yttrium, lanthanum, cerium, praesodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and thorium can be synthesized using this method. 

Photophysical properties of Th(TPP)(acac)2 have also been examined and compared with those of the trimeric species [Th(TPP)(OH)2]3 (Tran-Thi et al. 1992). The fluorescence of the porphyrin (3t,jt ) state is severely quenched in both compounds (triplet state (Tp 208 ps). The triplet yield of the trimer (0.38), however, is drastically reduced with respect to that of the monomer (1.00) even though the former contains three thorium atoms. This has been attributed to the enhancement of the probability of deactivation of the singlet excited states via an internal conversion pathway. 

The checker could not detect the formation of Ce porphines even after 26 hr. t La, Pr, and Ce porphyrins tend to demetalate on purification. Thorium porphyrins are difficult to isolate in a pure state. 

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