Actinide complexes isocyanide

Cycloheptatrienes with chromium, 5, 337 in molybdenum carbonyls, 5, 480 tj7-Cycloheptatrienyl complexes, with tungsten carbonyls and isocyanides, 5, 693 Cycloheptatrienyl compounds actinide complexes, 4, 227 with actinides, 4, 226 lanthanide complexes, 4, 122... 

There are scattered reports on isocyanide complexes of other metals including copper and gold, vanadium, and several lanthanides and actinides. 

The analogous uranium(III) compounds also show unusual reactivity patterns. For example, addition of COT to (Cp )3U yields a mixed metallocene dimer (18) bridged by a COT ligand in this reaction, the (Cp )3U complex has effectively acted as a formal three-electron reductant (equation 3)." A variety of substituted (Cp )3U complexes form adducts with CO and CNR (isocyanides) - these are rare examples of actinide metals with r-acidic ligands." Paramagnetic uranium alkyl complexes are active in a range of catalytic processes." ... 

Theoretical studies [59] indicate that the lowest unoccupied molecular orbital (LUMO) of such molecules is localized primarily on the acyl carbon atom, similarly to the situation in Fischer complexes. An example of such a compound is shown in Fig. 23.9, where the shortness of the Th-O distance (2.37(2) A) relative to Th-Cg (2.44(2) A) is unprecedented for a dihapto-acyl. A second example of an actinide dihapto-acyl is shown in Fig. 23.10. It should be noted that the orientation of the C-O vector is in the opposite direction from that in Fig. 23.9. The relative magnitudes of the Th-O and Th-C distances appear to reflect both the orientation of the C-O vector and conjugation with the arene n system. The intricate chemistry exhibited by actinide dihapto-acyls is summarized in Fig. 23.11. Important reactions include C-C coupling to form monomeric (10) or dimeric enediolates [57,58,60,61], isomerization to yield enolates (//) [60,62], catalytic hydrogenation to yield alkoxides (/2) [63], CO tetramerization to form dionediolates (13) [62, 64], coupling with ketenes 14), coupling with CO and phosphines 15) [62, 64], and addition to isocyanides to yield ketenimines [62, 64] 16). 

---