ISSN:
0009-2940
Keywords:
Aza-closo-decaboranes, halogenation of, methylation of
;
Aza-closo-dodecaboranes, halogenation of, methylation of
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The aza-closo-boranes ArNB9H9 (1, Ar = p-ClC6H4) and MeNB11H11 (2) were brominated, iodinated, or methylated under Friedel-Crafts conditions to give ArNB9H4Br5 (3), ArNB9H7I2 (4), ArNB9H4Me5 (7), MeNB11H10Br (5), MeNB11H10I (6), and MeNB11H5Me6 (9), respectively. The upper boron belt adjacent to nitrogen is not involved in the substitution reactions with 1 and 2. The antipodal position and the lower belt are attacked by electrophiles in the case of 1; the antipodal position is the preferred one in the case of 2. By prolongated action of triflic acid on the methylated species 7 and 9, one methyl group is replaced by the triflate group to give ArNB9H4Me4(OTrf) (8) and MeNB11H5Me5-(OTrf) (10) with this group in the positions 6 and 12, respectively. The NMR data indicate the cluster symmetries Cs (4, 8), C4v (3, 7), and C5v (5, 6, 9, 10). Crystal structure investigations of 5 (space group Cc) and 10 (space group C2/c) showed that the molecular dimensions of the NB11 skeleton are comparable to those of closo, -(PhCH2)NB11H11.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19961291014
