Observation of pentacarbonylchromium on flash photolysis of hexacarbonylchromium in cyclohexane solution

Kelly, John M.; Hermann, H; Gustorf, Ernst Koerner von

doi:10.1039/c39730000105

Cited by 58 publications

(24 citation statements)

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“…Evidence for the formation of organometallic alkane complexes in solution was first provided by flash photolysis studies of Cr(CO) 6 in cyclohexane [21] and perfluoromethylcyclohexane [22]. The Cr(CO) 5 intermediate was observed to have an increased lifetime in cyclohexane compared to perfluoromethylcyclohexane.…”

Section: Group VI Metal Carbonyl Alkane Complexesmentioning

confidence: 97%

Formation and reactivity of organometallic alkane complexes

Cowan

George

2008

Coordination Chemistry Reviews

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Section: Group VI Metal Carbonyl Alkane Complexesmentioning

confidence: 97%

Formation and reactivity of organometallic alkane complexes

Cowan

George

2008

Coordination Chemistry Reviews

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“…We have used picosecond time-resolved infrared spectroscopy to directly monitor the photolysis of Cp*Re(CO) 3 in scCH 4 and demonstrated that the initially generated Cp*Re(CO) 2 (CH 4 ) forms an equilibrium mixture of Cp*Re(CO) 2 (CH 4 )/Cp*Re(CO) 2 (CH 3 )H within the first few nanoseconds. The ratio of alkane to alkyl hydride complexes varies in the order CpRe(CO) 2 (C 2 H 6 ):CpRe(CO) 2 …”

Section: Characterization Of Organometallic Methane and Ethane Complementioning

confidence: 99%

“…This was interpreted to indicate a significant interaction between the matrix material and the vacant coordination site of the photofragment. Organometallic alkane complexes were first observed in solution at room temperature following photolysis of Cr(CO) 6 in cyclohexane solution, which showed that Cr(CO) 5 (cyclohexane) is formed within 50 ns after photolysis [2,3]. Further ultrafast studies have demonstrated that solvation actually occurs within the first picosecond following photolysis [4,5].…”

Section: Introductionmentioning

confidence: 97%

Recent advances in organometallic alkane and noble gas complexes

Calladine

Vuong

Sun

et al. 2009

Pure and Applied Chemistry

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Fast time-resolved infrared (TRIR) spectroscopy has been useful for studying the reactions of a wide range of organometallic alkane and noble gas complexes at ambient temperature following irradiation of metal carbonyl precursor complexes. The reactivity of organometallic alkane and xenon complexes decreases both across and down groups V, VI, and VII, and for a given metal/ligand combination the alkane and xenon complexes have similar reactivities. Systematic studies of reactivity have produced long-lived Re complexes which have allowed such complexes to be characterized using NMR spectroscopy. A new approach using liquid propane at low temperature as a solvent to monitor the interaction of such weakly coordinating ligands with transition-metal centers is outlined. TRIR studies monitoring the coordination and activation of methane and ethane in supercritical methane and liquid ethane solvents at room temperature are also reviewed.

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“…These molecules decay in the NMR experiments by reaction either with expelled CO reforming starting material, or with CpM(CO) 3 to form Cp 2 M 2 (CO) 5 , or with itself to form Cp 2 M 2 (CO) 4 , or with residual impurities to form CpM(CO) 2 L (M = Mn or Re). [55][56][57] The rates of decay will depend linearly on the concentration of the incoming reagent if the reaction is associative.…”

Section: ' Introductionmentioning

confidence: 99%

Manganese Alkane Complexes: An IR and NMR Spectroscopic Investigation

et al. 2011

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Manganese propane and manganese butane complexes derived from CpMn(CO)(3) were generated photochemically at 130-136 K with the alkane as solvent and characterized by FTIR spectroscopy and by (1)H NMR spectroscopy with in situ laser photolysis. Time-resolved IR spectroscopic measurements were performed at room temperature with the same laser wavelength. The ν(CO) bands in the IR spectra of the photoproducts in propane are shifted to low frequency with respect to CpMn(CO)(3), consistent with formation of CpMn(CO)(2)(propane). The (1)H NMR spectra conform to the criteria for alkane complexes: a high-field resonance for the η(2)-CH protons that shifts substantially on partial deuteration of the alkane and exhibits a coupling constant J(C-H) on (13)C-labeling of ca. 120 Hz. The NMR spectrum of each system exhibits two diagnostic product resonances in the high-field region for the η(2)-CH protons, corresponding to CpMn(CO)(2)(η(2)-C1-H-alkane) and CpMn(CO)(2)(η(2)-C2-H-alkane) isomers. Partial deuteration of the alkane at C1 results in characteristic strong isotopic perturbation of equilibrium of the η(2)-CH resonance of CpMn(CO)(2)(η(2)-C1-H-alkane). With propane-(13)C(1), the η(2)-CH resonance of CpMn(CO)(2)(η(2)-C1-H-alkane) isomer exhibits (13)C satellites with J(C-H) = 119 Hz. The corresponding resonance of CpMn(CO)(2)(η(2)-C2-H-alkane) is identified by use of propane-2,2-d(2). The lifetimes of the (η(2)-C1-H-alkane) isomers of the manganese complexes were determined by NMR spectroscopy as 22 ± 2 min at 134 K (propane) and 5.5 min at 136 K (butane). The corresponding spectra and lifetimes of the CpRe(CO)(2)(alkane) complexes were measured for reference (CpRe(CO)(2)(propane) lifetime ca. 60 min at 161 K; CpRe(CO)(2)(butane) 13 min at 171 K). The lifetimes determined by IR spectroscopy were similar to those determined by NMR spectroscopy, thereby supporting the assignments. These measurements extend the range of alkane complexes characterized by NMR spectroscopy from rhenium and rhodium derivatives to include less stable manganese derivatives.

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Observation of pentacarbonylchromium on flash photolysis of hexacarbonylchromium in cyclohexane solution

Cited by 58 publications

References 0 publications

Formation and reactivity of organometallic alkane complexes

Formation and reactivity of organometallic alkane complexes

Recent advances in organometallic alkane and noble gas complexes

Manganese Alkane Complexes: An IR and NMR Spectroscopic Investigation

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