Nach einem Autoxidationsmechanismus verläuft die Oxidation von Alkanen und Alkenen mit tBuOOH und O2 unter den Bedingungen der fluorigen Zweiphasenkatalyse. Die in Perfluorheptan löslichen ...katalytisch aktiven Komplexe bilden sich dabei in situ aus dem Liganden 1 und dem Mn2+‐Komplex 2 (mit polyfluorierten Carboxylatliganden).
Nach einem Autoxidationsmechanismus
verläuft die Oxidation von Alkanen und Alkenen mit
t
BuOOH und O
2
unter den Bedingungen der fluorigen Zweiphasenkatalyse. Die in Perfluorheptan löslichen ...katalytisch aktiven Komplexe bilden sich dabei in situ aus dem Liganden
1
und dem Mn
2+
‐Komplex
2
(mit polyfluorierten Carboxylatliganden).
magnified image
Resonance Raman (RR) spectroscopy of oxidised rubredoxin (Rd(,ox)) and the analog Fe(S(,2)-o-xyl)(,2)('-1), both containing the basic FeS(,4) core, has revealed subtle differences in their spectra. ...The spectra are also decidedly non-tetrahedral in nature. These differences have been shown by normal mode calculations to be due to distortions in the tetrahedral angles and also due to conformational differences in the Fe-S-C-C framework. Rd(,ox)RR spectra from D.gigas, D.sulfuricans and M.elsdenii are very similar implying similar conformational structure. RR spectrum of D.gigas disulforedoxin resembled that of rubredoxin but showed appreciable upshifts in one band possibly reflecting S-Fe-S angle distortions, which might be associated with the adjacency of two cysteine residues in the primary structure. The RR spectra of the 2Fe-2S proteins spinach ferredoxin and adrenodoxin were obtained. The assignments of the bridging and terminal stretching modes was accomplished by using ('34)S bridged proteins. Labelled proteins were prepared by efficient enzymatic insertion of ('34)S at the bridging position by using the enzyme rhodanese isolated from beef liver. The RR and IR spectra of the analog Fe(,2)S(,2)(S(,2)-o-xyl)(,2)('-2) and Fe(,2)S(,2)Cl(,4)('-2) is presented. Normal mode calculations confirm the assignments. X-ray absorption edge spectroscopy (XAES) and Extended X-ray absorption fine structure (EXAFS) studies of native bovine carbonic anhydrase (BCA) and Co substituted BCA are described. The K-edge results for the Zn enzyme support the model that the ionisation of a group coordinated to the metal controls and activity of the enzyme. EXAFS studies at different pH values indicate that there is no discernible change in coordination number of average metal ligand distance. The Co edge spectra also show changes with pH though no shifts could be measured due to the broad nature of the edges. The EXAFS analysis of CoBCA has revealed that the average metal-ligand distance changes by as much as 0.05 A on going from acidic to basic pH. The mechanistic implications of this difference in Zn and Co EXAFS are discussed.
