The ring and I: Air‐ and water‐stable 1,2‐diphosphetanes (see structure) were prepared in high yield utilizing the unique electronic and structural properties of 1,2‐dicarba‐closo‐dodecaborane(12)s. Ring‐opening reactions with elemental iodine gave the first 1,2‐bis(iodophosphanyl)‐1,2‐dicarba‐closo‐dodecaborane(12)s.

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The first carborane triflates, namely, 1-trifluoromethanesulfonylmethyl-o-carborane (2) and 1,2-bis(trifluoromethanesulfonylmethyl)-o-carborane (7), were obtained in high yields in the reactions of 1-hydroxymethyl-o-carborane (1) or 1,2-bis(hydroxymethyl)-o-carborane (6) with triflic anhydride (Tf2O) in CH2Cl2 in the presence of pyridine. When an excess of pyridine is employed, 1-o-carboranylmethylpyridinium triflate (3), which retains a closo-icosahedral structure, or a pyridinium salt (4) with a zwitterionic nido-dicarbaundecaborate anion are obtained from 1, while the nido compound 8 is formed from 6. The reaction of compound 2 or 7 with excess pyridine also gave 3 or 8, respectively. Compound 2 proved to be a convenient carboranylmethylating agent which reacts with nucleophiles (e.g., potassium phthalimide, PPh3 or KCN) to give the corresponding substitution products N-[(o-carboranyl-1-yl)methyl]phthalimide (9), o-carboranylmethylphosphonium salt 10, and 1-cyanomethyl-o-carborane (11). All compounds were characterized by 1H and 11B NMR spectroscopy. The structures of compounds 4, 7 and 8 were established by X-ray analysis.

This work was concerned with the simultaneous measurement of the combination coefficients b and 70, between small ions and aerosol particles and between small ions and uncharged aerosol particles respectively, for different particle radii.The ion-ion mutual repulsion coefficient y was first evaluated from 14 plots of small ion decay in an aerosol-free mylar vessel, which gave a mean experimental value of 2.39 (k 0.14) x 10-8 cm3 s-1.The decay of ions in the presence of aerosol particles in the mylar vessel was recorded and compared with a family of computed theoretical ion-aerosol decay curves to determine b. 70 could then be determined from the concentration of uncharged nuclei present. In the ten experiments carried out b ranged from 0.50 to 2 . 2 4~ 10-8 cm3 s-1 and 70 ranged from 0.33 to 2-39 x 10-6 cm3 s-1, for corresponding radii of 1.26 and 4.0 x 10-6 cm.Satisfactory agreement was found between the b and 70 versus radius results and various theoretically computed values. Possible reasons for discrepancies between theory and experiment are indicated.

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