Cyclam Ni

Ni-cyclam, Ni(CR), or Ni(tet a) can be used efficiently as catalyst in DMF, and in the presence of NH4CIO4 as proton source [71-74]. Ni species generated electrochemically react rapidly with organic halides to generate alkyl, alkenyl, or aryl radicals which add intramolecularly to a double or triple bond, then leading to cyclopentanoids (Table 7, entries 3-7a). 

The Ni(I) complex of tetramethylated cyclam, [Ni(TMC)]+, generated from the corresponding Ni(II) complex by electrochemical or photochemical methods, reacts with alkyl halides (RX) (133,140-143). It is a radical reaction, generating R transients and/or Ni-alkyls, which then decay to form alkanes, alkenes, and dimeric or cyclic organics. 

Cyclam)Ni(II) complexes react readily with methyl radicals [12]. The resulting (cyclam)Ni(III)-CH3 intermediates transform with excess radiolytically generated methyl radicals to ethane and reform the initial Ni(II) complex. The kinetics was determined. 

Kimura et al. have prepared bifunctional complexes [Ru(bpy)2(bpy-cyclam-Ni)] " and [Ru(phen)2(phen-cyclam-Ni)], in which the reac-... 

Bis-AT-alkylated complexes of Me2-9 and Me2-ll, as well as the tetra-methylated Ni(II)cyclam (Ni TMC) derivatives, have been synthesized by the deprotonation of secondary amines followed by alkylation (.34, 47,48). When EtI or other alkyl halide with jS-hydrogen was added to the deprotonated Ni(II) complex of cyclam or 11, HX elimination occurred instead of 8 2 reaction. Therefore, ethylene gas was produced instead of iV-ethylated complex formation when EtI was added to the deprotonated complex of cyclam or 11. However, in the case of 8, bis-iV-ethylated Ni(II) complex was isolated. This may be because HX elimination is slower than 8 2 reaction. The bis-iV-alkylated Ni(II) complexes of 9 (Me2-9 and Et2-9) and Me2-ll were stable against ligand dissociation in acidic aqueous solutions. The iV-alkylated complexes were dealkylated when the complexes were heated in aqueous solutions (34, 47). 

Fig.48 Molecular structure of [(cyclam)Ni[(/r-Cl)U(Me2Pz)4]2]. Hydrogen atoms omitted for clarity...

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