Synthesis of an organogallium(I) compound [Ga(CH2CMe2Ph)](n) with EPR spectral evidence for gallium clusters

The organogallium(I) compound [Ga(CH2CMe2Ph)](n) has been prepared by the r eduction of Ga(CH2CMe2Ph)(2)Cl by using either sodium or lithium with napht halene in THF. The yellow dihydronaphthalene gallium(III) intermediate M-2( C10H8[Ga(CH2CMe2Ph)(2)Cl](2)) initially formed at -78 degrees C but then de composed at higher temperatures to form [Ga(CH2CMe2Ph)](n), Ga(CH2CMe2Ph)(3 ) and MCl. EPR spectra, which were recorded as the two yellow intermediates Na-2(C10H8[Ga(CH2CMe2R)(2)Cl](2)) (R = Ph, Me) decomposed, indicated the p resence of radicals. The first and second derivatives of the EPR signals, l ine-widths, g-values and hyperfine coupling constants are consistent with t he radicals being clusters of organogallium species. The experimental spect ra were simulated by the superposition of two spectra, a single Gaussian sh aped line with a peak-to-peak width of 14 mT (92%) with the spectrum of fiv e equivalent gallium nuclei, A = 2.1 mT (8%). The even number of lines obse rved in the experimental spectra indicate an odd number of gallium nuclei w ith at least five bring required to give the number of observed lines. (C) 1999 Elsevier Science S.A. All rights reserved.