uu.seUppsala universitets publikationer
Ändra sökning
Avgränsa sökresultatet
1 - 18 av 18
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Agback, M
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för kvantkemi.
    Lunell, S
    Hussenius, A
    Matsson, O
    Theoretical studies of proton transfer reactions in 1-methylindene1998Ingår i: ACTA CHEMICA SCANDINAVICA, ISSN 0904-213X, Vol. 52, nr 5, s. 541-548Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    The base-catalysed 1,3-proton transfer reactions in 1-methylindene have been studied theoretically in polar (water) and unpolar (cyclohexane) solvents, respectively, for two different choices of bases, namely ammonia and trimethylamine (TMA), using the SM

  • 2. AUNE, M
    et al.
    BERGSON, G
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Kemiska institutionen.
    MATSSON, O
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Kemiska institutionen.
    1,3-HYDRON TRANSFER IN SOME 5-SUBSTITUTED AND 7-SUBSTITUTED 1-METHYLINDENES - ENANTIOSELECTIVITIES AND ENANTIOMER-DEPENDENT KINETIC ISOTOPE EFFECTS1995Ingår i: JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, ISSN 0894-3230, Vol. 8, nr 6, s. 400-406Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Base-catalysed substrate-enantioselective 1,3-hydron transfer (kinetic resolution) was studied in the indene system. A series of 1-methylindenes substituted in the aromatic ring [5-methoxy- (2), 5-fluoro- (3), 5-nitro- (4) and 7-nitro (5)] and 1-methylindene (1) were employed as substrates. The rate constants, the enantioselectivities and the kinetic isotope effects (KIEs) for the enantioselective reactions [(k(H)/k(D))(+) and (k(H)/k(D))(-)] were determined at 20 degrees C using (+)-(8R, 9S)-dihydroquinidine as chiral catalyst in the solvent o-dichlorobenzene. The rate constants vary according to the electronic effects of the substituents, The primary deuterium KIE, ranging from 4 . 73 [for (+)-(S)-2] to 11 . 3 [for (-)-(R)-5], is correlated with the rate constants as expected on the basis of the Melander-Westheimer postulate, The introduction of a substituent in the aromatic ring decreases the enantioselectivity, All compounds except 5 show the same sense of the enantioselectivity [k(+)/k(-)>1; all substrates used are (+)-(S)/(-)-(R)], The enantiomer dependence of the KIE is most pronounced for 1 [(k(H)/k(D))(+) = 5 . 71 and (k(H)/k(D))(-) = 6 . 46] and vanishes for the most acidic substrates (4 and 5).

  • 3.
    Aune, Marie
    et al.
    Uppsala universitet.
    Gogoll, Adolf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Kemiska institutionen.
    Matsson, Olle
    Uppsala universitet.
    Solvent Dependence of Enantioselectivity for a Base Catalyzed 1,3-Hydron Transfer Reaction: A Kinetic Isotope Effect and NMR Spectroscopic Study.1995Ingår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 60, nr 5, s. 1356-1364s. 1356-1364Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The base-catalyzed rearrangement of 1-methylindene (1) to 3-methylindene (2) has been studied. The reaction proceeds with substrate enantioselectivity (kinetic resolution) when chiral tertiary amines are used as catalysts. When dihydroquinidine (DHQD) (3

  • 4. Dybala-Defratyka, Agnieszka
    et al.
    Rostkowski, Michal
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Kemiska institutionen. Institutionen för biokemi och organisk kemi, Organisk kemi II. Organisk kemi.
    Westaway, Kenneth C.
    Paneth, Piotr
    A New Interpretation of Chlorine Leaving Group Kinetic Isotope Effects; A Theoretical Approach2004Ingår i: J. Org. Chem., Vol. 69, s. 4900-4905Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The chlorine leaving group kinetic isotope effects (KIEs) for the SN2 reactions between methyl chloride and a wide range of anionic, neutral, and radical anion nucleophiles were calculated in the gas phase and, in several cases, using a continuum solvent model. In contrast to the expected linear dependence of the chlorine KIEs on the Ca-CI bond order in the transition state, the KIEs fell in a very small range (1.0056-1.0091), even though the Ca-CI transition state bond orders varied widely from approximately 0.32 to 0.78, a range from reactant-like to very product-like. This renders chlorine KIEs, and possibly other leaving-group KIEs, less useful for studies of reaction mechanisms than commonly assumed. A partial explanation for this unexpected relationship between the Ca-CI transition state bond order and the magnitude of the chlorine KIE is presented.

  • 5. Fang, Yao-ren
    et al.
    MacMillar, Susanna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi, Organisk kemi II.
    Eriksson, Jonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    Kolodziejska-Huben, Magdalena
    Dybala-Defratyka, Agnieszka
    Paneth, Piotr
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi, Organisk kemi II.
    Westaway, Kenneth Charles
    The Effect of Solvent on the Structure of the Transition State for the SN2 Reaction between Cyanide Ion and Ethyl Chloride in DMSO and THF Probed with Six Different Kinetic Isotope Effects2006Ingår i: J. Org. Chem, nr 71, s. 4742-4747Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The secondary a- and B-deuterium, the a-carbon, the nucleophile carbon, the nucleophile nitrogen, and the chlorine leaving group kinetic isotope effects forthe SN2 reaction between cyanide ion an dethyl chloride were determined in the very slightly polar solvent THF at 30 C. A comparison of these KIEs with those reported earlier for the same reaction in the polar solvent DMSO shows that the transition state in THF is only sligthly tighter with very slightly shorter NC-Ca-CI bonds. This minor change in transition state structure does not account for the different transition structures that were earlier suggested by interpreting the experimental KIEs and the gas-phase calculations, respectively. It therefore seems unlikely that the different transition states suggested by the two methods are due to the lack of appropriate solvent modeling in the theoretical calculations. Previously it was predicted that the transition state of SN2 reactions where the nucleophile and the leaving group have the same charge would be unaffected by a charge in solvent. The experimental KIEs support this view.

  • 6.
    MacMillar, Susanna
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    Fang, Yao-ren
    Westaway, Kenneth C.
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    Beronius, Per
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Avdelningen för analytisk farmaceutisk kemi.
    Solvent effects on ion pairing of tetra-n-butylammonium cyanide: A conductometric study2008Ingår i: Journal of Physical Organic Chemistry, ISSN 0894-3230, E-ISSN 1099-1395, Vol. 21, nr 3, s. 237-241Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Tetra-n-butylammonium cyanide (n-Bu4NCN) is a commonly used reagent, for example, for the synthesis of nitriles. Recently n-Bu4NCN has been used as the nucleophilic reagent in kinetic isotope effect studies of nucleophilic aliphatic substitution reactions. The present research concerns the aggregation status (dissociated ions, ion pairs, higher aggregates) and transport properties of n-Bu4NCN in water, dimethyl sulfoxide (DMSO), and tetrahydrofuran (THF), at 25 C as studied by means of precision conductometry. These properties are of great importance since both non-polar and dipolar aprotic solvents are commonly used in the applications. In water as solvent the equilibrium constant for ion-pair formation, K-p =10.1 and the limiting molar conductivity, Lambda(o)= 102.4 cm(2) Omega(-1) mol(-1). The corresponding values for DMSO are K-p =1.98 +/- 0.19 and Lambda(o) = 34.59 +/- 0.03 cm(2) Omega(-1) mol(-1). These data imply that the degree of dissociation, in contrast to the expectations, is higher in DMSO than in water at the same salt concentration. In THF, the conductance as a function of concentration shows a minimum typical for solvents with low relative permittivity, indicating the formation of higher aggregates. The equilibrium constant for ion-pair formation and conductivity in THF is K-p=58.4 X 10(3) and Lambda(o)=9.81 cm(2) Omega(-1) mol(-1).

  • 7.
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    En dos stryknin: Om gifter och giftmord i litteraturen2012Bok (Övrig (populärvetenskap, debatt, mm))
  • 8.
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Från opium till radjaidjah2013Ingår i: Tintinism: Årsbok 2013 / [ed] Björn Wahlberg, Solna: Generation T - Den svenska Tintinföreningen i samarbete med Asterion Media , 2013, s. 73-82Kapitel i bok, del av antologi (Övrig (populärvetenskap, debatt, mm))
  • 9.
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Gifter från växter och djur: Några exempel från kriminallitteraturen2013Ingår i: Biologen, ISSN 0345-1127, Vol. 78, nr 4, s. 16-20Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 10.
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Giftig läsning i böckernas värld2013Ingår i: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 110, nr 34-35, s. 1484-1486Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 11.
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Inte bara arsenik: Om gifter och giftmord i kriminallitteraturen2013Ingår i: Bokvennen, ISSN 0802-1953, Vol. 25, nr 1, s. 56-63Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 12.
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi, Organisk kemi II.
    Isotope Effects for Exotic Nuclei2006Ingår i: Isotope Effects in Chemistry and Biology, CRC Press, Taylor & Francis Group, NW , 2006, s. 417-431Kapitel i bok, del av antologi (Refereegranskat)
  • 13.
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Kemiska institutionen.
    Libens merito: festskrift till Stig Strömholm på sjuttioårsdagen 16 september 20012001Samlingsverk (redaktörskap) (Övrig (populärvetenskap, debatt, mm))
  • 14.
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Mordisk litteratur generöst tryfferad med gift2012Ingår i: Upsala nya tidning, Vol. 122, nr 342Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 15.
    Matsson, Olle
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi, Organisk kemi II.
    Dybala-Defratyka, A.
    Rostkowski, M.
    Paneth, P.
    Westaway, K.C.
    A Theoretical Ivnestigation of a-Carbon Kinetic Isotope Effects and Their Relationship to the Transition-State Structure of SN2 Reactions2005Ingår i: J. Org. Chem., nr 70, s. 4022-4027Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The transition structures and a-carbon 12C/13C kinetic isotope for 22 SN2 reactions between methyl chloride and a wide variety of nucleophiles have been calculated using the B1LYP/aug-cc-pVDZ level of theory. Anionic, neutral, and radical anion nucleophiles were used to give a wide range of SN2 transition states so the relationship between the magnitude of the a-carbon kinetic isotope effect and trasition-state structure could be determined. The results suggest that the a-carbon 12C/13C kinetic isotope effects for SN2 reactions will be large (near the experimental maximum) and that the curve relating the magnitude of the KIE to the percent transfer of the a-carbon from the nucleophile to the leaving group in the transition state has a broad maximum. This means very similar KIEs will be found for early, symmetric, and late transition states and that one cannot use the magnitude of these KIEs to estimate transition-state structure.

  • 16.
    Matsson, Olle
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    MacMillar, Susanna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    Isotope effects for fluorine-18 and carbon-11 in the study of reaction mechanism2007Ingår i: Journal of labelled compounds & radiopharmaceuticals, ISSN 0362-4803, E-ISSN 1099-1344, Vol. 50, nr 11-12, s. 982-988Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The use of kinetic isotope effects (KIEs) for the short-lived radionuclides 11C and 18F in the study of reaction mechanisms is described using some examples. Leaving group fluorine KIEs (k 18/k19) have been utilized to determine the rate-limiting step for nucleophilic aromatic substitution reactions (SNAr). The fluorine KIE was also used to probe the effect of changing solvent and nucleophile steric hindrance on rate-limiting step. The mechanism for a base promoted elimination reaction was determined to be stepwise (E1cB) by a multiple KIE study including the leaving group fluorine KIE. The transition state structures for aliphatic nucleophilic substitution reactions (SN2) have been investigated by multiple KIE studies for cases where the substrate substitution, leaving group or solvent has been varied. Carbon KIEs for labelled α-carbon atom in the substrate are large, k11/k14 = 1.189-1.220. For labelled nucleophile cyanide ion. k11/k 14 = 0.99951-1.0119.

  • 17.
    Sawadjoon, Supaporn
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Sjöberg, Per J R
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Analytisk kemi.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Fysikalisk-organisk kemi.
    Samec, Joseph S M
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Mechanistic Insights into the Pd-Catalyzed Direct Amination of Allyl Alcohols: Evidence for an Outer-sphere Mechanism Involving a Palladium Hydride Intermediate2014Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, nr 6, s. 1520-1524Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The mechanism of direct amination of allyl alcohol by a palladium triphenylphosphite complex has been explored. Labelling studies show that the reaction proceeds through a π-allylpalladium intermediate. A second-order dependence of reaction rate on allyl alcohol concentration was observed. Kinetic isotope effect studies and ESI-MS studies are in agreement with a reaction proceeding through a palladium hydride intermediate in which both O-H bond and C-O bond cleavages are involved in rate-determining steps. A stereochemical study supports an outer-sphere nucleophilic attack of the π-allylpalladium intermediate giving complete chiral transfer from starting material to product.

  • 18. Westaway, Kenneth C.
    et al.
    Fang, Yao-ren
    MacMillar, Susanna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    Matsson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    Poirier, Raymond A.
    Islam, Shahidul M.
    A New Insight into Using Chlorine Leaving Group and Nucleophile Carbon Kinetic Isotope Effects To Determine Substituent Effects on the Structure of SN2 Transition States2007Ingår i: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 111, nr 33, s. 8110-8120Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Chlorine leaving group k(35)/k(37), nucleophile carbon k(11)/k(14), and secondary alpha-deuterium [(k(H)/k(D))(alpha)] kinetic isotope effects (KIEs) have been measured for the S(N)2 reactions between para-substituted benzyl chlorides and tetrabutylammonium cyanide in tetrahydrofuran at 20 degrees C to determine whether these isotope effects can be used to determine the substituent effect on the structure of the transition state. The secondary alpha-deuterium KIEs indicate that the transition states for these reactions are unsymmetric. The theoretical calculations at the B3LYP/aug-cc-pVDZ level of theory support this conclusion; i.e., they suggest that the transition states for these reactions are unsymmetric with a long NC-C-alpha and reasonably short C-alpha-Cl bonds. The chlorine isotope effects suggest that these KIEs can be used to determine the substituent effects on transition state structure with the KIE decreasing when a more electron-withdrawing para-substituent is present. This conclusion is supported by theoretical calculations. The nucleophile carbon k(11)/k(14) KIEs for these reactions, however, do not change significantly with substituent and, therefore, do not appear to be useful for determining how the NC-C-alpha transition-state bond changes with substituent. The theoretical calculations indicate that the NC-C-alpha bond also shortens as a more electron-withdrawing substituent is placed on the benzene ring of the substrate but that the changes in the NC-C-alpha transition-state bond with substituent are very small and may not be measurable. The results also show that using leaving group and nucleophile carbon KIEs to determine the substituent effect on transition-state structure is more complicated than previously thought. The implication of using both chlorine leaving group and nucleophile carbon KIEs to determine the substituent effect on transition-state structure is discussed.

1 - 18 av 18
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf