METALLAVIOLENES. AN ESR STUDY

Article abstract of DOI:10.1016/S0022-328X(00)98503-6

The preparation and ESR-spectroscopic characterization of radical complexes <(RnM)L(MRn)> cation radical with L=4,4'-bipyridine is described, where MRn=BePh, MgPh, ZnPh, ^-BEt3, GaMe2, InMe2 and SiMe3.While the bis(trimethylsilyl) derivative could be obtained via one-electron oxidation of the corresponding 4,4'-(1H, 1'H)-bipyridinylidene, the other complexes were prepared by the reaction of 4,4'-bipyridine with potassium and the organometal MRn+1 or the halide XMRn in THF.Use of organo-cadmium or -thallium compounds in such a procedure leads to deposition of the metals.The Grignard reagents MgPh2 and BrMgPh reduce 4,4'-bipyridine in an electron transfer process to yield an unsymmetrical complex.The new organometallic 4,4'-bipyridinium ( violene ) radical complexes can be incorporated into a series of related radicals which exhibits the sensitivity of the unpaired electron distribution towards metal coordination.