ROOM-TEMPERATURE SYNTHESIS OF (LIMO3SE3)N AND THE DETERMINATION OF THE RELATIVE REDUCTION POTENTIAL OF TERT-BUTYLLITHIUM

A room-temperature synthesis of the inorganic polymer (LiMo3Se3)n by r eductive intercalation is described. Instead of the traditional prepar ation by ion exchange at approximately 460-degrees-C, (LiMo3Se3)n was prepared by treating (InMo3Se3)n with a 10-fold excess of tert-butylli thium in pentane/toluene at 23-degrees-C for 1 week. While there is so me reductive attack of the (Mo3Se3-). chain core, reductive intercalat ion of lithium competed successfully to form (LiMo3Se3)n, as confirmed by X-ray powder diffraction, TEM, SEM microprobe, and product solubil ity in polar solvents. Proton NMR spectroscopy was used to confirm tha t tert-butyllithium reacts by a radical disproportionation process, pr oviding lithium atoms that diffuse into the interstitial spaces of the inorganic polymer matrix. The nonreversible reduction potential of te rt-butyllithium was estimated at 0.83 V above Li/Li+ by preparation of the reference solid Li0.37WO2. Knowledge of this potential has allowe d us to assign tert-butyllithium a relative position within the relati ve hierarchy of organolithium reagents commonly used in the reductive intercalation of solids.