Actinide complexes geometry

The nonacoordination is fairly common for the lanthanide and the actinide complexes. Two (Fig. 27) idealized geometries have been proposed 93) for nonacoordinated polyhedra (i) the monocapped square antiprism (C41,) and (ii) the s-tricapped trigonal prism (Hs ). Out of these two geometries, the symmetrically tricapped trigonal prism is more common than the monocapped square antiprism and it was not imtil early 1970 s that this C v) geometry has been positively identified in lanthanide complexes. However, Hoard et al. 209) may have observed this geometry in [Ln(EDTA) (OH2) 3] complex but were unable to recognize it. 

Table 5.10 Coordination Numbers and Coordination Geometry of Some Actinide Complexes...

Table5. Geometry of monomeric eight-coordinate actinide complexes with bidentate ligands...

TABLE I. COMPARISON OF COORDINATION GEOMETRIES IN BISCYCLO-PENTADIENYL ACTINIDE COMPLEXES a... 

Table III. Geometry of Monomeric Eight-Coordinate Actinide Complexes with Bidentate Ligands...

Finally, of the two actinide complexes 76 129] and 77 I30. 76 has the simple structural motif of 4 and a normal geometry around magnesium... 

Actinide complexes, 1129-1220 coordination numbers, 1131 geometry, 1131 kinetic stability, 1130 steric effects, 1130 Aciinide(III) complexes, 1131-1136 amides, 1133 ammines, 1131 antipyrine, 1134 aqua,1133... 

As already shown, DFT methods can be used to describe and explain the reactivity of actinide complexes, even when SET is involved. Interestingly, it is worth noting that DFT allowed theoretical treatment of the experimental systems. In particular, the geometry and... 

Although several phenyl derivatives of the lanthanides and actinides have been characterized, only one re-arene complex of the / transition metals is known to date. This is the uranium(III) benzene complex, U(AlCl4)s CeHe 153), prepared by the combination of uranium tetrachloride, aluminum trichloride and aluminum powder in refluxing benzene, the Fischer-Hafner method [154). The molecular geometry of the complex is shown in Fig. 18. 

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