- Laser pulse photolysis and transient infrared investigation into the effect of solvent or substituents (X) on the reactivity of photogenerated (η6-C6H6-yXy)Cr(CO)2 intermediates
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Time-resolved infrared spectroscopy identified the first observable species following nanosecond laser photolysis of (benzene)Cr(CO)3 in alkane solution as (benzene)Cr(CO)2(alkane). UV/ vis-monitored laser flash photolysis was used to observe the reaction of this species with CO. The reactivity toward CO of the primary photoproducts derived from related arene complexes (arene = C6H5Cl, C5H5Me, p-ClC6H4Me, C6H5Et, C6H5But, o- and p-C6H4Me2, C6H3Me3, C6Me6, C6Et6) were also determined by this technique. The rate of reaction with CO was found to depend on the alkane solvent and on the nature and degree of substitution of the arene ligand. The enthalpies of activation for all reactions were constant (24 ± 2 kJ mol-1), while the entropy of activation increased upon methyl substitution of the arene and upon a change in the solvent from cyclohexane to a linear alkane.
- Creaven, Bernadette S.,George, Michael W.,Ginzburg, Allan G.,Hughes, Catherine,Kelly, John M.,Long, Conor,McGrath, Irene M.,Pryce, Mary T.
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p. 3127 - 3131
(2008/10/08)
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- A simple route to (η6-arene)tricarbonylchromium complexes and a systematic study of different catalysts for complexation of arenes with Cr(CO)6
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A systematic investigation was made of the catalytic effect of different substances on complexation of toluene with Cr(CO)6. 1-3 molar equivalents of butyl acetate in refluxing decalin was found to be the best catalyst, providing that the complexation was carried out in a special apparatus described earlier.Comparable yields were obtained also in butyl acetate as a solvent, but the reaction time was more than doubled.The utility of the method was verified by complexation of 7 different benzene derivatives.
- Hudecek, Milan,Toma, Stefan
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p. 147 - 151
(2007/10/02)
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- The study of catalyst effects on the complexation of arenes with Cr(CO)6. An overview
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New results from our thorough investigation of different catalystic effects on the rate and yields of complexation of arenes with Cr(CO) are presented with a short review of the subject.With decalin as solvent the following substances were found to be the best catalysts: butyl acetate, ethyl formate, and dimethyl succinate.Butyl acetate proved to be the catalyst also in di-n-butyl ether.Special attention was paid to the complexation of naphthalene, and chlorobenzene.Some unsuccessful attempts at asymmetric induction of complexation are also described.
- Hudecek, Milan,Gajda, Vladimir,Toma, Stefan
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p. 155 - 160
(2007/10/02)
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- Regioselective Nucleophilic Additions to Tricarbonyl(η6-arene)chromium(0) complexes: Electronic versus Chelation Control
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Regioselective addition of t-butyl-lithium to tricarbonyl(η6-benzyl alcohol)chromium(0) proceeds to give tricarbonyl(η6-5-methylene-6-exo-t-butylcyclohexa-1,3-diene)chromium(0), which can be isomerised to tricarbonyl(η6-o-
- Blagg, Julian,Davies, Stephen G.,Goodfellow, Craig L.,Sutton, Kevin H.
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p. 1133 - 1144
(2007/10/02)
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- Synthesis of Tricarbonyl(η6-paracyclophane)chromium. Smallest-Bridged Paracyclophane-Metal Complex
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Tricarbonyl(η6-paracyclophane)chromium has been synthesized and its spectral properties have been investigated.
- Tobe, Yoshito,Nakayama, Atsuyoshi,Kobiro, Kazuya,Kakiuchi, Kiyomi,Odaira, Yoshinobu
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p. 1549 - 1550
(2007/10/02)
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- Regioselective Nucleophilic Additions to (η6-Benzyl alcohol)tricarbonylchromium: Isolation and X-Ray Crystal Structure of the Intermediate (η6-5-Methylene-6-exo-t-butylcyclohexa-1,3-diene)tricarbonylchromium
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Treatment of (η6-benzyl alcohol)tricarbonylchromium with alkyl-lithium compounds (t-BuLi; MeLi-tetramethylethylenediamine; n-BuLi; PhLi) regioselectively generates the corresponding η6-5-methylene-6-exo-alkylcyclohexa-1,3-diene compl
- Blagg, Julian,Davies, Stephen G.,Goodfellow, Craig L.,Sutton, Kevin H.
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p. 1283 - 1285
(2007/10/02)
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