Salts of 12-alkyl and 12-phenyl derivatives of the CB11H12 - anion are prepared in 50−60% yields from the 12-iodo-CB11H11 - anion by Pd-catalyzed cross-coupling with Grignard reagents. The tropylium ylide 12-C7H6 +-CB11H11 - is made in 54% yield by reaction of C7H7 + with CB11H12 -. Its ground-state dipole moment is 11.25 ± 0.1 D and its first hyperpolarizability is β = 236 × 10-30 esu at 1064 nm, as determined by hyper-Rayleigh scattering measurement. This value is ten times that of p-nitroaniline and is surprisingly large considering that the compound is colorless.

Reaction between nido-B10H14 (1) and elemental sulfur in CHCl3 in the presence of Et3N at room temperature, followed by treatment with Et3N.BH3 at 170-190 degrees C, resulted in the isolation of closo-1-SB11H11 (2) in 50% yield. Selected electrophilic halogenation reactions of compound led to the isolation of a series of monohalogenated derivatives of general constitution 12-X-closo-1-SB11H10 (12-X-, where X = Cl, Br, and I). The structures of 12-Cl- and 12-I- were determined by an X-ray diffraction analysis and the structures of all compounds were geometry optimised at the RMP2(fc)/6-31G* level. The constitution of all compounds is consistent with the results of mass spectrometry and multinuclear (1H and 11B) spectroscopy complemented by two-dimensional [11B-11B]-COSY and 1H{11B(selective)} NMR measurements. Experimental 11B chemical shifts generally show acceptable agreement with theoretical values calculated by GIAO methods, but spin-orbit coupling must be included for nuclei bearing heavy-atom substituents such as Br or I. The dipole moments determined for the B12-X bonds show similarities to those of aliphatic C-X bonds and confirm unambiguously the B12 --> S dipole moment orientation in the SB11 cage.