Actinide-to-carbon sigma bonds

The purpose of this article is to review recent results on the carbonylation chemistry of actinide-to-carbon sigma bonds, bearing in mind the unique properties of 5f-organometallics cited above. We focus our attention on the properties of bis(pentamethylcyclopentadienyl) actinide acyls. Just as transition metal acyls (A) occupy a pivotal role in classical carbonylation chemistry, it will be seen that many of the unusual... 

ABSTRACT, This chapter presents an overview of recent chemical progress involving molecules with actinide-to-carbon and actinide-to-hydrogen sigma bonds. The synthetic, structural, chemical/mechanistic, thermochemical, and bonding aspects of this chemistry are developing at a rapid rate. 

However, at low temperatures, all of these hydrides react rapidly (l.e., at a rate which is rapid on the nmr time scale by ca. -40 C) and reversibly with CO to yield bright-yellow complexes, which are formulated on the basis of spectroscopic data as dihaptoformyls [82,83] (eq.(64)). There is no infrared spectroscopic evidence for actinide carbonyl complexes. The enedlolate forming reaction is too rapid to allow complete characterization of the Wa-derlved formyl. In regard to thermodynamics, it is found by van t Hoff measurements that for 3Cb, AH - -4.5(9) kcal/mol, AS = -11.7(4.3) e.u. and for Ya—Yb, AH = -5.9(1.5) kcal/mol, AS = -23.9(7.4) e.u.. Migratory Insertion of carbon monoxide into an actlnlde-to-hydrogen sigma bond is clearly exothermic [83]. 

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