Crystal structures of metallocene complexes with uranium–germanium bonds

The first structural examples of complexes with uranium–germanium bonds are presented, namely, bis[3,5-bis(trifluoromethyl)phenyl-2κC 1](hydrido-2κH)(iodido-1κI)bis[1,1(η5)-pentamethylcyclopentadienyl]germaniumuranium(Ge—U), [GeU(C10H15)2(C8H3F6)2HI], and bis[3,5-bis(trifluoromethyl)phenyl-2κC 1](fluorido-1κI)(hydrido-2κH)bis[1,1(η5)-pentamethylcyclopentadienyl]germaniumuranium(Ge—U), [GeU(C10H15)2(C8H3F6)2FH]. The two complexes both have a long U—Ge bond [distances of 3.0428 (7) and 3.0524 (7) Å].

Fair Look at Coordination Oligomerization of Higher α-Olefins

Coordination catalysis is a highly efficient alternative to more traditional acid catalysis in the oligomerization of α-olefins. The distinct advantage of transition metal-based catalysts is the structural homogeneity of the oligomers. Given the great diversity of the catalysts and option of varying the reaction conditions, a wide spectrum of processes can be implemented. In recent years, both methylenealkanes (vinylidene dimers of α-olefins) and structurally uniform oligomers with the desired degrees of polymerization have become available for later use in the synthesis of amphiphilic organic compounds and polymers, high-quality oils or lubricants, and other prospective materials. In the present review, we discussed the selective dimerization and oligomerization of α-olefins, catalyzed by metallocene and post-metallocene complexes, and explored the prospects for the further applications of the coordination α-olefin dimers and oligomers.

Equilibria and mesomerism/valence tautomerism of group 4 metallocene complexes

Priority of equilibrium: reactivity of unusual group 4 metallocene complexes is best explained by the equilibrium and only additionally by the mesomerism/valence tautomerism. The equilibrium predominates the empirically found experimental results.