Klinge, Michael

[["dc.bibliographiccitation.firstpage","1205"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS"],["dc.bibliographiccitation.lastpage","1222"],["dc.bibliographiccitation.volume","219"],["dc.contributor.author","Buback, M."],["dc.contributor.author","Kling, M."],["dc.contributor.author","Schmatz, S."],["dc.date.accessioned","2018-11-07T08:50:10Z"],["dc.date.available","2018-11-07T08:50:10Z"],["dc.date.issued","2005"],["dc.description.abstract","Rate coefficients of beta-scission reactions in tertiary alkoxy radicals, R(CH3)(2)CO (R = methyl, ethyl, tert-butyl and neo-pentyl) have been estimated via density functional theory (DFT) calculations in conjunction with statistical unimolecular rate theory. For tert-butoxy, results obtained by employing different basis sets are compared with experimental values, indicating that UB3LYP/6-31G(d,p) excellently predicts kinetic data. Rate coefficients for inter- and intramolecular hydrogen abstraction are also reported. Depending on R, the P-scission rate may vary by orders of magnitude. The predicted temperature dependence of the alcohol-to-ketone product ratios for alkoxy radical decomposition in a hydrocarbon environment is in remarkably close agreement with the corresponding ratios measured on the product mixtures from decomposition of tert-butyl and tert-amyl peroxyacetates in solution of n-heptane."],["dc.identifier.doi","10.1524/zpch.2005.219.9.1205"],["dc.identifier.isi","000232490800002"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/21635"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Oldenbourg Verlag"],["dc.relation.issn","0942-9352"],["dc.title","Decomposition of tertiary alkoxy radicals"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","26"],["dc.bibliographiccitation.journal","ChemInform"],["dc.bibliographiccitation.volume","37"],["dc.contributor.author","Abel, B."],["dc.contributor.author","Buback, M."],["dc.contributor.author","Grimm, Ch."],["dc.contributor.author","Kling, M."],["dc.contributor.author","Schmatz, S."],["dc.contributor.author","Schroeder, J."],["dc.date.accessioned","2021-12-08T12:29:29Z"],["dc.date.available","2021-12-08T12:29:29Z"],["dc.date.issued","2006"],["dc.identifier.doi","10.1002/chin.200626278"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/96098"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-476"],["dc.relation.eissn","1522-2667"],["dc.relation.issn","0931-7597"],["dc.rights.uri","http://doi.wiley.com/10.1002/tdm_license_1.1"],["dc.title","Femtochemistry of Organic Peroxides: Ultrafast Formation and Decarboxylation of Carbonyloxy Radicals"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","13274"],["dc.bibliographiccitation.issue","43"],["dc.bibliographiccitation.journal","Journal of the American Chemical Society"],["dc.bibliographiccitation.lastpage","13278"],["dc.bibliographiccitation.volume","125"],["dc.contributor.author","Abel, Bernd"],["dc.contributor.author","Buback, M."],["dc.contributor.author","Kling, M."],["dc.contributor.author","Schmatz, S."],["dc.contributor.author","Schroeder, J."],["dc.date.accessioned","2018-11-07T10:35:22Z"],["dc.date.available","2018-11-07T10:35:22Z"],["dc.date.issued","2003"],["dc.description.abstract","The photoinduced (266 nm) ultrafast decarboxylation of the peroxyester tert-butyl 9-methylfluorene-9-percarboxylate (TBFC) in solution has been studied with femtosecond time resolution. While the photodissociation of TBFC occurs too fast to be resolved, the intermediate 9-methylfluorenylcarbonyloxy radical (MeFl-CO2) decarboxylates on a picosecond time scale. The latter process is monitored by pump-probe absorption spectroscopy at wavelengths between 400 and 883 nm. The measured transient absorbance signals reveal a dominant fast decay with a lifetime of a few picoseconds and, to a minor extent, a slow component with a lifetime of about 55 ps. Statistical modeling of MeFl-CO2 decarboxylation employing molecular parameters calculated by density functional theory suggests that the fast component is associated with the decarboxylation of vibrationally hot radicals, whereas the 55 ps decay reflects the dissociation of thermally equilibrated MeFl-CO2 at ambient temperature. The vast majority of MeFl-CO2 radicals thus decarboxylate on a time scale about an order of magnitude faster than expected from the time constant of 55 ps reported by Falvey and Schuster for this reference reaction. This literature value turns out to refer to decarboxylation rate of MeFl-CO2 at ambient temperature."],["dc.identifier.doi","10.1021/ja036304d"],["dc.identifier.isi","000186123900058"],["dc.identifier.pmid","14570504"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/45082"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.relation.issn","0002-7863"],["dc.title","A seemingly well understood light-induced peroxide decarboxylation reaction reinvestigated with femtosecond time resolution"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","9499"],["dc.bibliographiccitation.issue","45"],["dc.bibliographiccitation.journal","The Journal of Physical Chemistry A"],["dc.bibliographiccitation.lastpage","9510"],["dc.bibliographiccitation.volume","107"],["dc.contributor.author","Abel, Bernd"],["dc.contributor.author","Assmann, J."],["dc.contributor.author","Buback, M."],["dc.contributor.author","Grimm, C."],["dc.contributor.author","Kling, M."],["dc.contributor.author","Schmatz, S."],["dc.contributor.author","Schroeder, J."],["dc.contributor.author","Witte, T."],["dc.date.accessioned","2018-11-07T10:34:44Z"],["dc.date.available","2018-11-07T10:34:44Z"],["dc.date.issued","2003"],["dc.description.abstract","Experimental and theoretical investigations on the ultrafast photoinduced decomposition of three tert-butyl peroxides of general structure R-C(O)O-O-tert-butyl with R = phenyloxy, benzyl, or naphthyloxy in solution are presented. Photoinduced O-O bond scission occurs within the time resolution (200 fs) of the pump-probe experiment. The subsequent dissociation of photochemically excited carbonyloxy radicals, R-CO2, has been monitored on a picosecond time scale by transient absorption at wavelengths between 290 and 1000 nm. The measured decay of R-CO2 is simulated via statistical unimolecular rate theory using molecular energies, geometries, and vibrational frequencies obtained from density functional theory (DFT) calculations. The results are compared with recent data for tert-butyl peroxybenzoate (R = phenyl). While benzoyloxy radicals exhibit nanosecond to microsecond lifetimes at ambient temperature, insertion of an oxygen atom or a methylene group between the phenyl or naphthyl chromophore and the CO2 moiety significantly decreases the stability and thus lowers the lifetime of the carbonyloxy radicals in solution to picoseconds. The reasons behind this structural effect on decomposition rate are discussed in terms of barrier heights for decarboxylation on the ground-state potential energy surface and of a fast reaction channel via electronically excited states of carbonyloxy radicals. Arrhenius parameters are reported for thermal rate constants, k(T), of R-CO2 decarboxylation as deduced from modeling of the time-resolved experimental data in conjunction with the DFT calculations."],["dc.identifier.doi","10.1021/jp0350823"],["dc.identifier.isi","000186425000002"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/44941"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.relation.issn","1089-5639"],["dc.title","Ultrafast decarboxylation of carbonyloxy radicals: Influence of molecular structure"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.journal","ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY"],["dc.bibliographiccitation.volume","224"],["dc.contributor.author","Kling, M."],["dc.contributor.author","Abel, Bernd"],["dc.contributor.author","Assmann, J."],["dc.contributor.author","Buback, M."],["dc.contributor.author","Schmatz, S."],["dc.date.accessioned","2018-11-07T10:10:31Z"],["dc.date.available","2018-11-07T10:10:31Z"],["dc.date.issued","2002"],["dc.format.extent","U165"],["dc.identifier.isi","000177422300840"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/39870"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.publisher.place","Washington"],["dc.relation.issn","0065-7727"],["dc.title","Experimental and theoretical studies into mechanisms of ultrafast UV-induced decarboxylation in organic peroxide decomposition."],["dc.type","conference_abstract"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","717"],["dc.bibliographiccitation.journal","ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS"],["dc.bibliographiccitation.lastpage","735"],["dc.bibliographiccitation.volume","215"],["dc.contributor.author","Buback, M."],["dc.contributor.author","Kling, M."],["dc.contributor.author","Seidel, M. T."],["dc.contributor.author","Schott, F. D."],["dc.contributor.author","Schroeder, J."],["dc.contributor.author","Steegmuller, U."],["dc.date.accessioned","2018-11-07T09:41:01Z"],["dc.date.available","2018-11-07T09:41:01Z"],["dc.date.issued","2001"],["dc.description.abstract","Picosecond UV pump (248.5 nm) / IR probe spectroscopy has been applied to the study of the decomposition of several aromatic diacyl peroxides, peroxycarbonates, and of a peroxyester dissolved in CH2Cl2. Measuring the IR transient absorbance in the 2100 to 2450 cm(-1) range allows to monitor the formation and vibrational relaxation of the photoproduct CO2 via the asymmetric stretching mode (vg) with a time resolution of 1.8 ps. With each of the six peroxides a CO2 molecule is released at delay times below 10 ps. The energy relaxation of the initially formed vibrationally hot CO2 is followed over the time range up to 500 ps. Analysis of the transient IR spectra, via an anharmonic oscillator model proposed by Hamm et al. [1], shows a monoexponential decay of internal energy. Irrespective of the type of peroxide a single relaxation time of 67 +/- 5 ps is found to adequately represent the cooling behavior of CO2 in liquid CH2Cl2. The \"initial\" temperatures of vibrationally hot CO2 at a delay time of 20 ps after applying the pump pulse differ considerably, between 1400 and 2700 K for the decompositions of tert-butyl benzoyl peroxide and tert-butyl benzoyl carbonate, respectively. These remarkably high temperatures are assumed to originate from energy release associated with structural relaxation of the bent OCO moiety to form the linear CO2 molecule."],["dc.identifier.doi","10.1524/zpch.2001.215.6.717"],["dc.identifier.isi","000169740100003"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/33632"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Oldenbourg Verlag"],["dc.relation.issn","0942-9352"],["dc.title","Picosecond IR study of UV-induced peroxide decomposition: Formation and vibrational relaxation of CO2 in CH2Cl2 solution"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","5441"],["dc.bibliographiccitation.issue","24"],["dc.bibliographiccitation.journal","Physical Chemistry Chemical Physics"],["dc.bibliographiccitation.lastpage","5455"],["dc.bibliographiccitation.volume","6"],["dc.contributor.author","Buback, M."],["dc.contributor.author","Kling, M."],["dc.contributor.author","Schmatz, S."],["dc.contributor.author","Schroeder, J."],["dc.date.accessioned","2018-11-07T10:53:06Z"],["dc.date.available","2018-11-07T10:53:06Z"],["dc.date.issued","2004"],["dc.description.abstract","Recent experimental and theoretical studies shed new light on the ultrafast photochemical decomposition of organic peroxides, R1C(O)O-OR2. This reaction both is of fundamental interest, directed toward a detailed understanding of unimolecular processes, and of practical relevance because of the widespread use of peroxides as initiators in free-radical polymerization. An overview is given on pico- and femtosecond UV pump-VIS/near IR/IR probe experiments on the decomposition of diaroyl peroxides (R-1 = aryl, R-2 = C(O)-R-1), of tert-butyl peroxyesters (R-1 = aryl or benzyl, R-2 = tert-butyl), and of tert-butyl peroxycarbonates (R-1 = aryloxy, R-2 = tert-butyl). Analysis of the time-resolved concentration profiles is carried out in conjunction with quantum-chemical calculations, in particular on the structure and reactivity of the intermediate carbonyloxy radicals, R-1-CO2. A semi-quantitative model is presented which allows for an adequate understanding of the ultrafast processes subsequent to instantaneous peroxide photodissociation."],["dc.identifier.doi","10.1039/b410875b"],["dc.identifier.isi","000225573600001"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/49274"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Royal Soc Chemistry"],["dc.relation.issn","1463-9076"],["dc.title","Photo-induced decomposition of organic peroxides: Ultrafast formation and decarboxylation of carbonyloxy radicals"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","5157"],["dc.bibliographiccitation.issue","26"],["dc.bibliographiccitation.journal","The Journal of Physical Chemistry A"],["dc.bibliographiccitation.lastpage","5167"],["dc.bibliographiccitation.volume","107"],["dc.contributor.author","Abel, Bernd"],["dc.contributor.author","Assmann, J."],["dc.contributor.author","Botschwina, Peter"],["dc.contributor.author","Buback, M."],["dc.contributor.author","Kling, M."],["dc.contributor.author","Oswald, Rainer B."],["dc.contributor.author","Schmatz, S."],["dc.contributor.author","Schroeder, J."],["dc.contributor.author","Witte, T."],["dc.date.accessioned","2018-11-07T10:37:43Z"],["dc.date.available","2018-11-07T10:37:43Z"],["dc.date.issued","2003"],["dc.description.abstract","The light-induced (266 nm) ultrafast decarboxylation of two peroxides R-1-C(O)O-OR2, with R-1 = phenyl and R-2 = benzoyl or tert-butyl, in solution has been studied on the picosecond time scale by absorption spectroscopy with a time resolution typically of 100 to 200 fs. The reaction was investigated in various solvents of different polarity and viscosity to elucidate the influence of the solvent environment on the decarboxylation rate. Transient intermediate benzoyloxy radicals, R-1-CO2, were monitored at wavelengths between 300 and 1000 nm. While the primary dissociation of the peroxide is too fast to be resolved, the dissociation of intermediate benzoyloxy radicals is clearly detected on the picosecond time scale. The mechanism of light-induced two-step dissociation is discussed, as is the dependence of reaction dynamics on the type of substituent R-2 as well as the branching ratio between prompt and delayed CO2 formation. A model for the decarboxylation process is presented that is based on molecular structure parameters and energies. The latter quantities, which are obtained from density functional theory calculations, serve as input data for calculations of the specific decomposition rate coefficients of benzoyloxy intermediates via statistical unimolecular rate theory. The predicted benzoyloxy radical decay data are compared with corresponding experimental concentration versus time traces."],["dc.identifier.doi","10.1021/jp034858x"],["dc.identifier.isi","000183811900003"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/45638"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.relation.issn","1089-5639"],["dc.title","Experimental and theoretical investigations of the ultrafast photoinduced decomposition of organic peroxides in solution: Formation and decarboxylation of benzoyloxy radicals"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","300"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Angewandte Chemie International Edition"],["dc.bibliographiccitation.lastpage","+"],["dc.bibliographiccitation.volume","42"],["dc.contributor.author","Abel, Bernd"],["dc.contributor.author","Assmann, J."],["dc.contributor.author","Buback, M."],["dc.contributor.author","Kling, M."],["dc.contributor.author","Schmatz, S."],["dc.contributor.author","Schroeder, J."],["dc.date.accessioned","2018-11-07T10:41:51Z"],["dc.date.available","2018-11-07T10:41:51Z"],["dc.date.issued","2003"],["dc.identifier.isi","000180578000004"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/46637"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-v C H Verlag Gmbh"],["dc.relation.issn","1433-7851"],["dc.title","Ultrafast decarboxylation of organic peroxides in solution: Interplay of different spectroscopic techniques, quantum chemistry, and theoretical modeling"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]