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Synthesis and ESR-characterization of radical anion complexes of lanthanum. X-ray crystal structure of the mixed bipy, bipy−1 complex of lanthanum(III) [LaI2(bipy)(bipy)(DME)]: evidence for an inter-ligand charge transfer

1996; Elsevier BV; Volume: 524; Issue: 1-2 Linguagem: Inglês

10.1016/s0022-328x(96)06425-x

1872-8561

M.N. Bochkarev, Igor L. Fedushkin, V. I. Nevodchikov, V.K. Cherkasov, Herbert Schumann, Holger Hemling, Roman Weimann,

Magnetism in coordination complexes

The reaction of [LaI2(THF)3]2[C10H8] with excess of 2,2′-bipyridine (bipy) in DME or THF results in the formation of mixed radical anion ligand/neutral ligand complexes [LaI2(bipy(0))(bipy(−1))(L)n (DME)(1) and (THF)2 (2), whereas a reactant reactant ratio of 1:2 generates the mono-bipy complex [LaI2(bipy)(DME)2] (3). ESR and IR spectroscopic data show a fast shuttle electron transfer (SIET) between the neutral and the radical anion of bipy in1 and2. The X-ray structure shows1 to be monoclinic, space group P2/c, Z = 2, with a = 10.0320(12), b = 9.7510(11), c = 16.296(8)A˚, β = 90.43(2)°. The structure was refined toR = 0.0360 for 2562 observed reflections (1 > 2σ(1)). It shows the lanthanum atom eight-coordinated by two iodine, two oxygen and four nitrogen atoms.