Transcript L-4-
Some New Allotropes Fullerenes: 5- and 6-membered rings arranged to form a “soccer ball” structure. Nanotubes: half of a C60 sphere fused to a cylinder of fused aromatic rings. => Common Names of Benzene Derivatives OH CH3 phenol toluene H C CH2 styrene OCH3 NH2 aniline anisole O O O C C C acetophenone CH3 benzaldehyde H OH benzoic acid => Disubstituted Benzenes The prefixes ortho-, meta-, and para- are commonly used for the 1,2-, 1,3-, and 1,4positions, respectively. Br Br o-dibromobenzene or 1,2-dibromobenzene NO2 HO p-nitrophenol or 4-nitrophenol => 3 or More Substituents Use the smallest possible numbers, but the carbon with a functional group is #1. OH O2N NO2 NO2 1,3,5-trinitrobenzene O2N NO2 NO2 2,4,6-trinitrophenol => Common Names for Disubstituted Benzenes CH3 O CH3 OH C OH CH3 CH3 m-xylene H3C CH3 mesitylene o-toluic acid H3C p-cresol => Phenyl and Benzyl Phenyl indicates the benzene ring attachment. The benzyl group has an additional carbon. Br phenyl bromide CH2Br benzyl bromide => Physical Properties Melting points: More symmetrical than corresponding alkane, pack better into crystals, so higher melting points. Boiling points: Dependent on dipole moment, so ortho > meta > para, for disubstituted benzenes. Density: More dense than nonaromatics, less dense than water. Solubility: Generally insoluble in water. => IR and NMR Spectroscopy C=C stretch absorption at 1600 cm-1. sp2 C-H stretch just above 3000 cm-1. 1H NMR at 7-8 for H’s on aromatic ring. 13C NMR at 120-150, similar to alkene carbons. => Mass Spectrometry => => UV Spectroscopy =>