A stacking interaction between a bridging hydrogen atom and aromatic pi density in the n-B18H22-benzene system.
The structures of n-B18H22 and of n-B18H22 x C6H6 were determined by single-crystal X-ray analysis at -60 degrees C. The geometry of the boron cluster itself does not seem to be appreciably affected by solvation. There does, however, appear to be an unusual interaction of a polyborane bridging hydrogen atom with the benzene pi system, giving rise to an extended stacked structure. The 1H{11B} spectrum of n-B18H22 in [D6]benzene differs from that in [D12]cyclohexane most noticeably in the bridging proton region. Upon moving from the aliphatic to the aromatic solvent, the greatest increase in shielding was for the signal corresponding to the bridge hydrogen atom that interacts with the pi system of benzene; the signal was shifted upfield by 0.49 ppm. Density functional theory calculations were performed on 1:1 and 2:1 complexes of the n-B18H22 unit with benzene.
Hamilton
Ewan J M
EJ
Department of Chemistry, The Ohio State University at Lima, Lima, Ohio 45804, USA. hamilton.40@osu.edu
Kultyshev
Roman G
RG
Du
Bin
B
Meyers
Edward A
EA
Liu
Shengming
S
Hadad
Christopher M
CM
Shore
Sheldon G
SG
D001554:Benzene / Q000737:chemistry*; D001896:Boron Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004583:Electrons; D006841:Hydrocarbons, Aromatic / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry*; D006860:Hydrogen Bonding; D012997:Solvents
D001896:Boron Compounds; D006841:Hydrocarbons, Aromatic; D012997:Solvents; D006859:Hydrogen; D001554:Benzene