Publication costs assisted by Michigan State UniversityChemical shifts of lithium-7 nucleus were measured in 11 nonaqueous solvents against 4.0 M aqueous lithium perchlorate solution. Lithium perchlorate, chloride, bromide, iodide, triiodide, and tetraphenylborate were used. The shifts ranged from +2.80 ppm for acetonitrile, down to -2.54 ppm for pyridine. In dimethyl sulfoxide and dimethylformamide no evidence for contact ion pairing was observed. Formation of contact ion pairs was particularly evident in tetrahydrofuran, nitromethane, and tetramethylguanidine. The large broadening of the 35C1 resonance of the perchlorate ion in these solvents is in agreement with the above explanation. In contrast to sodium-23 nmr, no correlation was found between limiting chemical shifts in different solvents and the Gutmann donor numbers of these solvents.

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An apparatus has been designed for the determination of microgram quantities of phosphorus-containing compounds. Both inorganic and organic compounds are reduced to phosphine under a stream of hydrogen in a quartz tube at 900-1000°C. The phosphine is separated from other combustion products on sequential alumina and porous polymer bead columns with final measurement by a thermionic GLC detector. The method routinely requires microgram samples with sensitivity capabilities to the nanogram level. The analysis time per sample is less than 5 min.