Nitrogen‐containing diiron‐hexacarbonyl complexes from 3‐phenyl‐2H‐azirines Reaction of 2,2‐dimethyl‐3‐phenyl‐2H‐azirine (1) with diiron‐enneacarbonyl yields as an insertion product, and in addition to other products, the diiron‐hexacarbonyl complex 2 (Scheme 1), whose structure was derived from spectral data, in particular 13C‐NMR.‐data (Table 1). With trimethylamine oxide in benzene, 2 is converted into the urea derivative 3, and yields with cerium (IV) ammonium nitrate the nitrate 4 (Scheme 1). The analogous complexes 6 and 9 have been obtained by irradiation of 1‐phenyl‐vinyl azide (5) and ironpentacarbonyl (Scheme 1) and from vinyl isocyanate (8) and diiron‐enneacarbonyl at 40° (Scheme 2), respectively. The azirine 1, an acetylenic compound and diiron‐enneacarbonyl in benzene react to give complexes of type 10 as the main product (Scheme 3). The structure of complex 10 has been established by X‐ray single crystals analysis. On the 13C‐NMR. time scale the carbonyl groups of compound 10 show a fluxional behaviour: below −50° the CO‐groups of one of the two Fe(CO)3‐groups undergo intranuclear exchange, above −50° the CO‐groups of both Fe(CO)3‐groups undergo intranuclear exchange. Tentative reaction mechanisms for the formation of the complexes of type 2 and 10 are formulated in Schemes 5, 6 and 7.

The preparation of exo-and endo-tricarbonyliron complexes (exo-and endo-5, -6, -8, and 9) of 2,3-dimethylidene-5-bicyclo[2.2. llheptene (l), -bicyclo[2.2.1]heptane (2), -5-bicyclo[2.2.2]octene (3) and -bicyclo[2.2.2]octane (4) is described. The complexes are obtained by thermal reaction of the bicyclic butadienes with diironenneacarbonyl in hexane solution. exo-and endo-5 are also formed photochemically from ironpentacarbonyl and 1 in pentane solution at -35". The structural assignment of exo-and endo-5 and -6 is based on their mass-spectra and on coordination shifts in 'Hand 13C-NMR.-spectra exo-and endo-6 are correlated with exo-and endo-5, respectively, by hydrogenation. Hydrogenation of the uncomplexed double bond in exo-and endo-5 occurs in both complexes from the ex0 side as shown by deuteration experiments. The free ligand 1 reacts in the same stereospecific manner.

Abstract---A complete analysis of the proton coupled lac spectrum of butadieneiron tricarbonyl is presented. The structure of the diene ligand is discussed on the basis of vicinal C,H and H,H coupling constants as well as 3 J ( H H ) , 'J(CH) and IJ(CC) data. These data are interpreted in terms of a non-planar C,H skeleton in which C.C bond lengths are nearly equal and the terminal carbon atoms exhibit some rehybridization towards sp3. The results obtained from the complex in solution agree with a structural model from X-ray data of substituted butadieneiron tricarbonyl complexes.

A theoretical treatment of the transients obtained in potentiostatic single pulse experiments on metal alloy/metal ion electrodes coupled to a redox reaction is presented. Formulas have been derived for the concentration of the electrochemically active component in the alloy and of the corresponding metal ions of different valent state which form the redox couple in the electrolyte, respectively, as a function of the distance from the interface and the duration of the voltage pulse. Expressions for the partial current densities carried by the two consecutive charge-transfer reactions, Me = Me z+ + zeand Me ~ § = Me (z+D § + e-, and for the total current density flowing through the cell have been worked out. Analysis of the current density transients on the basis of these expressions allows interpretation of experimental curves in terms of the characteristic kinetic parameters of the electrochemical system. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 139.80.123.34 Downloaded on 2015-07-02 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 139.80.123.34 Downloaded on 2015-07-02 to IP

Electrochemical reactions involving consecutive charge‐transfer steps as expressed by the reaction schema Sv=Sv+1+zve− v=1,2,…,n are considered assuming that the only irreversible processes are charge‐transfer and diffusion and that disproportionation of the intermediate reaction products does not occur. An arbitrary number of n consecutive steps is assumed where feasible, but detailed discussion is restricted to the experimentally best understood case of a two‐step reaction. A general description is given of the steady‐state current density‐overvoltage characteristics and for the current density vs. time curves in potentiostatic single‐pulse experiments and for the variation of overvoltage with time in galvanostatic single‐pulse experiments, respectively.