17: Aromatic Compounds
- Page ID
- 424334
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)learning objectives
After reading this chapter and completing ALL the exercises, a student can be able to
- summarize the discovery of the structure of benzene (refer to section 17.1)
- predict the physical properties of aromatic compounds using IMFs (refer to section 17.2)
- apply resonance and MO Theory to the structure of benzene (refer to section 17.3)
- apply MO Theory to cyclobutadiene (refer to section 17.4)
- apply resonance to aromatic compounds and ions (refer to sections 17.5 and 17.6)
- use Hückel’s rule to predict whether a given cyclic compound or ion is aromatic, antiaromatic or nonaromatic (refer to sections 17.5 and 17.6)
- for heterocycles, determine whether the lone pairs of the heteroatoms occupy p orbitals or sp2 orbitals (refer to sections 17.5 and 17.7)
- for heterocyclic amines, and predict whether the nitrogen atom is weakly or strongly basic (refer to sections 17.5 and 17.7)
- use Huckel's Rule to prdict whether polycyclic aromatic hydrocarbons are aromatic (refer to setions 17.5 and 17.8)
- use IR, NMR, UV and mass spectra to determine the structures of aromatic compounds (refer to section 17.9)
- given an aromatic compound, predict the important features of its spectra (refer to section 17.9)
Please note: IUPAC nomenclature and important common names of alcohols were explained in Chapter 3.
- 17.1: Introduction- The Discovery of Benzene
- It took chemists over 100 years to determine the structure of benzene.
- 17.2: The Structure and Properties of Benzene and its Derivatives
- Aromatic hydrocarbons contain ring structures with delocalized pi electron systems and are more stable than their saturated analogs.
- 17.3: Resonance and the Molecular Orbitals of Benzene
- Both resonance and Molecular Orbital Theory can be used to explain the stability of benzene.
- 17.4: The Molecular Orbital Picture of Cyclobutadiene
- Cyclobutadiene is very unstable. MO Theory helps explain this instability.
- 17.5: Aromaticity and Huckel's Rule
- In 1931, German chemist and physicist Erich Hückel proposed a theory to help determine if a planar ring molecule would have aromatic properties. His rule states that if a cyclic, planar molecule has 4n+2 π electrons, it is considered aromatic.
- 17.6: Aromatic Ions - a closer look
- Cyclic anions and cations can also be aromatic if they follow Huckel's Rule.
- 17.7: Heterocyclic Aromatic Compounds - a closer look
- The hybridization of heteroatoms in cyclic compounds can be sp2 to create aromaticity. For nitrogen containing heterocyclic compounds, the orbital occupied by the lone pair electrons determines whether the compound is weakly basic or neutral.
- 17.8: Polycyclic Aromatic Hydrocarbons
- Benzene rings may be joined together (fused) to give larger polycyclic aromatic compounds.
- 17.9: Spectroscopy of Aromatic Compounds
- The electron movement of the aromatic ring is evident in the spectroscopic data of aromatic compounds.
- 17.10: Additional Exercises
- This section has additional exercises for the key learning objectives of the chapter.
- 17.11: Solutions to Additional Exercises
- This section has the solutions to the additional exercises from the previous section.