Actinide carbonyl

While stable binary actinide carbonyls are still unknown, research in this area focused mainly on the detection and theoretical investigation of unstable molecules such as the monocarbonyl complexes of thorium and uranium. The possible molecular structures U-GO, U-OG, and GUO of carbon monoxide interacting on a uranium metal surface have been studied by density functional theory (DFT).14 GUO has been produced experimentally by reaction of laser-ablated U atoms with CO in excess argon and trapped in a triplet state in solid argon at 7 K.15 Studies of the reaction of thorium atoms with CO have been carried out. The reaction of laser-ablated thorium atoms with carbon monoxide in excess neon gave the first thorium carbonyl complex, Th-GO, which rearranges photochemically to CThO (Scheme l).16... 

At this juncture there appear to be some distinct similarities between the early transition metal and actinide carbonylation results. The enediolate products are, with the exception of mole-cularity, the same (cf. J, and I), although the insertion/coupling reaction appears to be much more rapid for thorium and uranium. 

Although stable, homoleptic, mononuclear, and polynuclear complexes of carbon monoxide can be prepared for almost every transition element, a number of experiments indicate that actinide carbonyls (e.g., U(CO)t )... 

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]. 

Although stable, homoleptic, mononuclear and polynuclear complexes of carbon monoxide are known for almost every transition element, a number of experiments indicate that actinide carbonyls (e.g. U(CO) ) are not stable at ambient temperature. However, uranium carbonyls can be prepared in cryogenic matrices [6,7]. Co-condensation of uranium vapor with CO in a 4K argon matrix yields species identifiable by infrared spectroscopy (in particular, Voo) uranium carbonyls, U(CO) . Derived force constants suggest bonding patterns rather similar to those observed for zero-valent early transition-element and lanthanide carbonyls. However, decomposition of these actinide carbonyls occurs at temperatures above about 30 K. 

Carbon monoxide [630-08-0] (qv), CO, the most important 7T-acceptor ligand, forms a host of neutral, anionic, and cationic transition-metal complexes. There is at least one known type of carbonyl derivative for every transition metal, as well as evidence supporting the existence of the carbonyls of some lanthanides (qv) and actinides (1) (see AcTINIDES AND THANSACTINIDES COORDINATION COMPOUNDS). 

The reaction is general and has been applied to many transition metals as well as lanthanides and actinides. Variants use metal carbonyls and other complexes to supply the capping unit, e.g. 

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... 

As already noted, the carbonylation of bis(pentamethyl-cyclopentadienyl) actinide hydrocarbyls is irreversible in the cases studied thus far. Thus, thermolysis does not result in CO loss, but rather in interesting chemical reactions. Thermolysis of 1 ( 5) in toluene solution results in hydrogen atom migration to yield an enolate (eq.(5)). NMR studies establish that eq.(5) is essentially quantitative, and that the stereochemical course... 

The aim of this Specialist Periodical Report is to cover in a comprehensive way the chemistry of the transition metals including the lanthanides and actinides. It includes published data on the metal carbonyls but does not necessarily include results concerned with organometallic complexes or spectroscopic data which are published elsewhere. 

A large number of urea and substituted urea complexes with actinide(IV) compounds are known in these the ligands are bonded to the metal via the carbonyl oxygen atom, and these complexes are therefore described in the section dealing with carboxylic add amide complexes (p. 1164). 

Carbonyl complexes with actinides, 4, 192 (7 5-acyclic)Re(CO)3 complexes, 5, 919 allylation, 10, 663 with allylic tins, 9, 354 into 7 3-allyl palladium complexes, 8, 364 arene chromium carbonyls... 

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... 

FT-ICR, see Fourier-transform ion cyclotron resonance Fullerene[60], germanium-germanium addition, 10, 748 Fullerenes with cobalt, 7, 51 on cobalt Cp rings, 7, 73 inside metallodendrimers, 12, 401 microwave applications, 1, 334 Pd rc-complexes, 8, 348 Ru—Os complexes, 6, 830 with tungsten carbonyls, 5, 687 )2-Fullerenes, with platinum, 8, 634 Fulvalene actinide complex, synthesis, 4, 232 Fulvalene chromium carbonyls, synthesis and characteristics, 5, 264... 

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