52491-41-5Relevant academic research and scientific papers
A transient infrared spectroscopy study of coordinatively unsaturated osmium carbonyl compounds
Bogdan, Paula L.,Weitz, Eric
, p. 639 - 644 (2007/10/02)
Transient infrared spectroscopy is used to study the coordinatively unsaturated osmium carbonyl fragments generated by 248-nm photolysis of gas-phase Os(CO)5. The nascent photoproducts, predominantly Os(CO)3 with some Os(CO)4, are highly reactive toward combination with both CO and Os(CO)5. The bimolecular rate constants for reaction of Os(CO)3 and Os(CO)4 with CO are 7.6 ± 0.9 and 5.5 ± 0.6 × 10-11 cm3 molecule-1 s-1, respectively. Infrared absorptions for a new unsaturated osmium species, Os2(CO)8, formed by reaction of Os(CO)3 with Os(CO)5, are assigned. The rate constant for this reaction is 2.7 ± 0.9 × 10-10 cm3 molecule-1 s-1, on the order of gas kinetic. The reactivities of the unsaturated osmium species are similar to those of the analogous ruthenium compounds and contrast with the reactivity of Fe(CO)4. The trends observed in the photochemistry of group 8 metal carbonyl complexes and the role of spin selection rules in the reactivity of these coordinatively unsaturated fragments are discussed. Continuing depletion of the Os(CO)5 parent after photolysis indicates that polynuclear osmium carbonyl clusters are formed.
The reactions of nitrosoarenes with cationic cyclohexadienyl complexes of iron tricarbonyl: an ESR study
Li, Lijuan,Perrier, Richard E.,Eaton, Donald R.,McGlinchey, Michael J.
, p. 1868 - 1877 (2007/10/02)
The reactions of nitrosoarenes with the (cyclohexadienyl)Fe(CO)3 cation have been investigated by using electron spin resonance spectroscopy.The radicals produced are nitroxides of the type (OC)3Fe(C6H7)(Ar)N-O* but, in some cases, disproportionation and loss of the metal carbonyl fragment leads to the corresponding C6H5(Ar)N-O* radical.With bulky nitrosoarenes, such as C6Me5NO, isomers are observed in which the aryl ring rotation is slow on the ESR time scale.The analogous reactions with the cyclohexadienyl cation derived from the B ring of (ergosteryl acetate)Fe(CO)3 lead to initial attack not at one of the termini of the delocalized system but rather at the central carbon, i.e., at C-7.Subsequent hydrogen migration leads to the (5,7-diene)Fe(CO)3 complex bearing the arylnitroxide at the 7-position.The mechanisms of these reactions are discussed.Key words: nitrosoarenes, iron cations, ESR.
Low-temperature photochemistry of matrix-isolated Fe(CO)4 complexes of α,β-unsaturated esters: C=C vs. ester group coordination
Gerhartz, Wolfgang,Grevels, Friedrich-Wilhelm,Klotzbücher, Werner E.
, p. 1850 - 1856 (2008/10/08)
Photolysis of various (η2-olefin)Fe(CO)4 complexes of α,β-unsaturated esters in low-temperature matrices shows that in all cases detachment of CO is the predominant photoreaction. However, instead of the expected (η2-olefin)Fe(CO)3 species three other Fe(CO)3 complexes are observed, in which the ester group is involved in bonding to the metal. Spectroscopic data indicate bonding of the organic ligand to the Fe(CO)3 moiety (a) in a η4-1-oxadiene type fashion, (b) via C=C double bond and the ester O-R group, and (c) solely via the ester carbonyl group. Under selective irradiation conditions haptotropic rearrangements involving these three complexes take place. For comparison the photolytic behavior of a (η4-vinyl ketone)Fe(CO)3 complex was investigated. Furthermore, studies in nitrogen-containing matrices aid in the assignments. In carbon monoxide containing matrices the photolytic detachment of the olefinic moiety, in addition to CO photodissociation, is indicated by the formation of Fe(CO)5.
