Benzene and aromaticity
|
|
|
- Lauren Mosley
- 5 years ago
- Views:
Transcription
1 aromaticity The word "benzene" derives historically from "gum benzoin", sometimes called "benjamin" (i.e., benzoin resin), an aromatic resin known to European pharmacists and perfumers since the 15th century as a product of southeast Asia. 1
2 Benzene and aromaticity before 1825 compounds with a distinctive "aromatic" smell 1825 Michael Faraday discovers benzene Aromaticity 2
3 Aromaticity Benzene and aromaticity : high carbon-hydrogen ratios - stable despite considerable unsaturation 1865: benzene structure Kekulé 3
4 Kekulé Something wrong!! Kekulé 4
5 1931 Linus Pauling 5
6 Aromaticity: IUPAC definition Compounds which exhibit significantly exalted diamagnetic susceptibility are aromatic. Cyclic electron delocalization also may result in bond length equalization abnormal chemical shifts magnetic anisotropies chemical and physical properties which reflect energetic stabilization. Aromatic compounds dichloro-dipheynl-tricholoethane, DDT Paul Muller receives a Nobel Prize for his discovery of the insecticidal properties of DDT 6
7 Aromatic compounds Aromatic compounds 7
8 Sources of Aromatic Hydrocarbons From high temperature distillation of coal tar Heating petroleum at high temperature and pressure over a catalyst stability 8
9 Unusual Stability Hydrogenation of just one double bond in benzene is endothermic! Annulenes All cyclic conjugated hydrocarbons were proposed to be aromatic. However, cyclobutadiene is so reactive that it dimerizes before it can be isolated. And cyclooctatetraene adds Br 2 readily. Look at MO s to explain aromaticity. 9
10 MO Rules for Benzene Six overlapping p orbitals must form six molecular orbitals. Three will be bonding, three antibonding. Lowest energy MO will have all bonding interactions, no nodes. As energy of MO increases, the number of nodes increases. MO s for Benzene 10
11 Energy Diagram for Benzene The six electrons fill three bonding pi orbitals. All bonding orbitals are filled ( closed shell ), an extremely stable arrangement. MO s for Cyclobutadiene 11
12 Energy Diagram for Cyclobutadiene Following Hund s rule, two electrons are in separate orbitals. This diradical would be very reactive. Polygon Rule The energy diagram for an annulene has the same shape as the cyclic compound with one vertex at the bottom. 12
13 Aromatic Requirements Structure must be cyclic with conjugated pi bonds. Each atom in the ring must have an unhybridized p orbital. The p orbitals must overlap continuously around the ring. (Usually planar structure) Compound is more stable than its openchain counterpart. Anti- and Nonaromatic Antiaromatic compounds are cyclic, conjugated, with overlapping p orbitals around the ring, but the energy of the compound is greater than its open-chain counterpart. Nonaromatic compounds do not have a continuous ring of overlapping p orbitals and may be nonplanar. 13
14 Hückel s Rule If the compound has a continuous ring of overlapping p orbitals and has 4N + 2 electrons, it is aromatic. If the compound has a continuous ring of overlapping p orbitals and has 4N electrons, it is antiaromatic. [N]Annulenes [4]Annulene is antiaromatic (4N e - s) [8]Annulene would be antiaromatic, but it s not planar, so it s nonaromatic. [10]Annulene is aromatic except for the isomers that are not planar. Larger 4N annulenes are not antiaromatic because they are flexible enough to become nonplanar. 14
15 annulenes MO Derivation of Hückel s Rule Lowest energy MO has 2 electrons. Each filled shell has 4 electrons. 15
16 Cyclobutadiene Cyclobutadiene wasn t prepared until 1965, by Pettit, but it dimerizes (Diels-Alder) even at -78 o C: Compounds With 4n π Electrons Are Not Aromatic (May be Antiaromatic) Planar, cyclic molecules with 4n π electrons are much less stable than expected (anti-aromatic) Cyclobutadiene is so unstable that it dimerizes by a self-diels-alder reaction even at low temperature 16
17 Compounds With 4n π Electrons Are Not Aromatic (May be Antiaromatic) If the ring is larger, it will distort out of planar and behave like an ordinary alkene 8-electron (and higher) compounds are not delocalized (single and double bonds) Cyclooctatetraene has four double bonds, reacting with Br 2, KMnO 4, and HCl as if it were four alkenes cyclooctatetraene Cyclopentadienyl Ions The cation has an empty p orbital, 4 electrons, so antiaromatic. The anion has a nonbonding pair of electrons in a p orbital, 6 e - s, aromatic. 17
18 Acidity of Cyclopentadiene pk a of cyclopentadiene is 16, much more acidic than other hydrocarbons. H H H + _ OC(CH 3 ) 3 + HOC(CH 3 ) 3 pka = 16 pka = 19 Tropylium Ion The cycloheptatrienyl cation has 6 p electrons and an empty p orbital. Aromatic: more stable than open chain ion H OH H +, H 2 O H + 18
19 Dianion of [8]Annulene Cyclooctatetraene easily forms a -2 ion. Ten electrons, continuous overlapping p orbitals, so it is aromatic. + 2 K + 2 K + Pyridine Heterocyclic aromatic compound. Nonbonding pair of electrons in sp 2 orbital, so weak base, pk b =
20 Pyrrole Also aromatic, but lone pair of electrons is delocalized, so much weaker base. Other Heterocyclics 20
21 Fused Ring Hydrocarbons Naphthalene Anthracene Phenanthrene Reactivity of Polynuclear Hydrocarbons As the number of aromatic rings increases, the resonance energy per ring decreases, so larger PAH s will add Br 2. H Br H Br Br H H Br (mixture of cis and trans isomers) 21
22 Fused Heterocyclic Compounds Common in nature, synthesized for drugs. Allotropes of Carbon Amorphous: small particles of graphite; charcoal, soot, coal, carbon black. Diamond: a lattice of tetrahedral C s. Graphite: layers of fused aromatic rings. 22
23 Some New Allotropes Fullerenes: 5- and 6-membered rings arranged to form a soccer ball structure. Nanotubes: half of a C 60 sphere fused to a cylinder of fused aromatic rings. Common Names of Benzene Derivatives OH CH 3 NH2 OCH 3 phenol toluene aniline anisole H C CH 2 O C CH 3 O C H O C OH styrene acetophenone benzaldehyde benzoic acid 23
24 Disubstituted Benzenes The prefixes ortho-, meta-, and para- are commonly used for the 1,2-, 1,3-, and 1,4- positions, respectively. Br NO 2 Br o-dibromobenzene or 1,2-dibromobenzene 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 O 2 N NO 2 O 2 N NO 2 NO 2 1,3,5-trinitrobenzene NO 2 2,4,6-trinitrophenol 24
25 Common Names for Disubstituted Benzenes CH 3 CH 3 O C OH CH 3 OH CH 3 H 3 C CH 3 H 3 C m-xylene mesitylene o-toluic acid p-cresol Phenyl and Benzyl Phenyl indicates the benzene ring attachment. The benzyl group has an additional carbon. Br CH 2 Br phenyl bromide benzyl bromide 25
26 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. sp 2 C-H stretch just above 3000 cm H NMR at δ7-δ8 for H s on aromatic ring. 13 C NMR at δ120-δ150, similar to alkene carbons. 26
27 Mass Spectrometry UV Spectroscopy 27
28 Spectroscopy of Aromatic Compounds IR: Aromatic ring C H stretching at 3030 cm 1 and peaks 1450 to 1600 cm 1 Spectroscopy of Aromatic Compounds UV: Peak near 205 nm and a less intense peak in nm range 1 H NMR: Aromatic H s strongly deshielded by ring and absorb between δ 6.5 and δ
29 Aryl and Benzylic protons: Ring Currents Aromatic ring oriented perpendicular to a strong magnetic field, delocalized π electrons producing a small local magnetic field which opposes the applied field in middle of ring but reinforces the applied field on the perimeter of the ring 29
30 13 C NMR of Aromatic Compounds Carbons in aromatic ring absorb at δ 110 to 140 Shift is distinct from alkane carbons but in same range as alkene carbons 30
31 Summary of Spectroscopy Carey/Useful/aromaticity.html PDF ext/react3.htm 31
Chapter 16 Aromatic Compounds. Discovery of Benzene
Chapter 16 Aromatic Compounds Discovery of Benzene Isolated in 1825 by Michael Faraday who determined C: ratio to be 1:1. Synthesized in 1834 by Eilhard Mitscherlich who determined molecular formula to
Organic Chemistry, 7 L. G. Wade, Jr. 2010, Prentice Hall
Organic Chemistry, 7 th Edition L. G. Wade, Jr. Chapter 16 Aromatic Compounds 2010, Prentice Hall Discovery of Benzene Isolated in 1825 by Michael Faraday who determined C:H ratio to be 1:1. Synthesized
Chapter 16. Aromatic Compounds
Chapter 16 Aromatic Compounds Discovery of Benzene Isolated in 1825 by Michael Faraday who determined C:H ratio to be 1:1. Synthesized in 1834 by Eilhard Mitscherlich who determined molecular formula to
Aromatic Compounds I
2302272 Org Chem II Part I Lecture 1 Aromatic Compounds I Instructor: Dr. Tanatorn Khotavivattana E-mail: tanatorn.k@chula.ac.th Recommended Textbook: Chapter 16 in Organic Chemistry, 8 th Edition, L.
Benzene and Aromaticity
Benzene and Aromaticity Why this Chapter? Reactivity of substituted aromatic compounds is tied to their structure Aromatic compounds provide a sensitive probe for studying relationship between structure
12/27/2010. Chapter 14 Aromatic Compounds
Nomenclature of Benzene Derivatives Benzene is the parent name for some monosubstituted benzenes; the substituent name is added as a prefix Chapter 14 Aromatic Compounds For other monosubstituted benzenes,
Benzene a remarkable compound. Chapter 14 Aromatic Compounds. Some proposed structures for C 6 H 6. Dimethyl substituted benzenes are called xylenes
Benzene a remarkable compound Chapter 14 Aromatic Compounds Discovered by Faraday 1825 Formula C 6 H 6 Highly unsaturated, but remarkably stable Whole new class of benzene derivatives called aromatic compounds
BENZENE AND AROMATIC COMPOUNDS
BENZENE AND AROMATIC COMPOUNDS The discovery of benzene: 1825 - Michael Faraday, empirical formula of C 1834 - Eilhard Mitscherlich synthesized benzin from gum benzoin, empirical formula C Aromatic The
Aromatic Compounds. A number of these compounds had a distinct odor. Hence these compounds were called aromatic
Aromatic Compounds Early in the history of organic chemistry (late 18 th, early 19 th century) chemists discovered a class of compounds which were unusually stable A number of these compounds had a distinct
Chapter 15 Benzene and Aromaticity
Chapter 15 Benzene and Aromaticity Aromatic Compounds Aromatic Originally used to describe fragrant substances Refers to a class of compounds that meets Hückel criteria for aromaticity 2 Aromatic Compounds
Organic Chemistry. Second Edition. Chapter 18 Aromatic Compounds. David Klein. Klein, Organic Chemistry 2e
Organic Chemistry Second Edition David Klein Chapter 18 Aromatic Compounds Copyright 2015 John Wiley & Sons, Inc. All rights reserved. Klein, Organic Chemistry 2e 18.1 Introduction to Aromatic Compounds
17.24 To name the compounds use the directions from Answer 17.3.
Benzene and Aromatic Compounds 7 7 7.2 If benzene could be described by a single Kekulé structure, only one product would form in Reaction [], but there would be four (not three) dibromobenzenes (A ),
Benzene and Aromatic Compounds
1 Background Benzene and Aromatic Compounds Benzene (C 6 H 6 ) is the simplest aromatic hydrocarbon (or arene). Benzene has four degrees of unsaturation, making it a highly unsaturated hydrocarbon. Whereas
BRCC CHM 102 Class Notes Chapter 13 Page 1 of 6
BRCC CHM 102 ass Notes Chapter 13 Page 1 of 6 Chapter 13 Benzene and Its Derivatives aliphatic hydrocarbons include alkanes, alkenes, and alkynes aromatic hydrocarbons compounds that contain one or more
18.1 Intro to Aromatic Compounds
18.1 Intro to Aromatic Compounds AROMATIC compounds or ARENES include benzene and benzene derivatives. Aromatic compounds are quite common. Many aromatic compounds were originally isolated from fragrant
BENZENE & AROMATIC COMPOUNDS
BENZENE & AROMATIC COMPOUNDS Dr. Zainab M Almarhoon 2 Learning Objectives By the end of chapter four the students will: Understand the resonance description of structure of benzene Understand the hybridization
DAMIETTA UNIVERSITY CHEM-103: BASIC ORGANIC CHEMISTRY LECTURES Dr Ali El-Agamey. Organic Chemistry, 7 th Edition L. G. Wade, Jr.
DAMIETTA UNIVERSITY CHEM-103: BASIC ORGANIC CHEMISTRY LECTURES 11-12 Dr Ali El-Agamey Organic Chemistry, 7 th Edition L. G. Wade, Jr. Amines 2010, Prentice Hall Reactions N,N-Disubstituted amides 2 o amine
Lecture 10. More Aromatics. February 15, Chemistry 328N
Lecture 10 More Aromatics February 15, 2018 ückel's Rule for Aromaticity To be Aromatic a compound must : 1. be Cyclic 2. have one P orbital on each atom in the ring 3. be planar or nearly so to give orbital
12.1 AROMATIC COMPOUNDS
12 Arenes and Aromaticity estradiol 12.1 AROMATIC COMPOUNDS O O O O C 3 C 3 O O safrole (oil of sassafras) O methyl salicylate (oil of wintergreen) O vanillin (vanilla) C 3 N C 3 C 3 CC 2 ibuprofen C C
Benzene and Aromatic Compounds. Chapter 15 Organic Chemistry, 8 th Edition John McMurry
Benzene and Aromatic Compounds Chapter 15 Organic Chemistry, 8 th Edition John McMurry 1 Background Benzene (C 6 H 6 ) is the simplest aromatic hydrocarbon (or arene). Four degrees of unsaturation. It
Chapter 15: Benzene & Aromaticity
Chapter 15: Benzene & Aromaticity Learning Objective & Key Concepts 1. Sources and nomenclature of aromatic compounds. 2. Introduction to Huckel 4n+2 rule and aromaticity stability and reactivity, 3. Introduction
ORGANIC - CLUTCH CH AROMATICITY.
!! www.clutchprep.com CONCEPT: AROMATICTY INTRODUCTION Aromatic compounds display an unusual stability for their high level of electron density. Their high level of unsaturation should make them extremely
2016 Pearson Education, Inc. Isolated and Conjugated Dienes
2016 Pearson Education, Inc. Isolated and Conjugated Dienes 2016 Pearson Education, Inc. Reactions of Isolated Dienes 2016 Pearson Education, Inc. The Mechanism Double Bonds can have Different Reactivities
Naming Aromatic Compounds (Benzene as the Parent)
aming Aromatic Compounds (Benzene as the Parent) If the the alkyl chain is smaller than the ring use the ring as the parent Monosubstituted benzenes are named the same way as other hydrocarbons using benzene
Chemistry 204: Benzene and Aromaticity
Chemistry 204: Benzene and Aromaticity Structure of and Bonding in Benzene benzene, C 6 H 6, was first isolated in 1825 (Michael Faraday), but it was not until more than 100 years later that an adequate
Chapter 12: Unsaturated Hydrocarbons
Chapter 12: Unsaturated Hydrocarbons UNSATURATED HYDROCARBONS contain carbon-carbon multiple bonds. Alkenes C=C double bonds Alkynes triple bonds Aromatics benzene rings 1 2 NAMING ALKENES Step 1: Name
16.4 Cyclobutadiene. .. H c)
16.4 CYCLOBUTADIEE 649 arranged about zero energy, it is necessary for one degenerate pair, 4 nb and 5 nb, to be located at zero energy. MOs at zero energy are termed nonbonding.) If the total number of
4 - BENZENE: AROMATICITY, CONJUGATION AND ASSOCIATED REACTIVITY
4 - BENZENE: AROMATICITY, CONJUGATION AND ASSOCIATED REACTIVITY During the early 1800's, a group of compounds of natural origin became collectively known as aromatic compounds. As several of these compounds
Benzene. Named benzene by Eilhardt Mitscherlich in < Molecular formula: C 6 H 6. < Representative of the aromatic hydrocarbon family:
Benzene < Discovered in 1825 by Michael Faraday: e called it bicarburet of hydrogen. Named benzene by Eilhardt Mitscherlich in 1833. < Molecular formula: C 6 6 < Representative of the aromatic hydrocarbon
Frost Circles a Great Trick
Aromatics Frost Circles a Great Trick Inscribe a polygon of the same number of sides as the ring to be examined such that one of the vertices is at the bottom of the ring The relative energies of the MOs
CHEM 263 Notes Sep 27, Equivalent resonance forms gives stability to a compound.
CEM 263 otes Sep 27, 2016 Aromatic Compounds Continued Aromaticity Equivalent resonance forms gives stability to a compound. resonance 1,2-dibromobenzene Aromatic compounds are especially stable. For benzene,
Benzenes & Aromatic Compounds
Benzenes & Aromatic Compounds 1 Structure of Benzene H H C C C H C 6 H 6 H C C C H H A cyclic conjugate molecule Benzene is a colourless odourless liquid, boiling at 80 o C and melting at 5 o C. It is
Chapter Tell whether the following compounds are ortho-, meta-, or para-disubstituted: (a) M-chlorotoluene (b) NO 2
Chapter 15 15.1 Tell whether the following compounds are ortho-, meta-, or para-disubstituted: (a) Cl C 3 M-chlorotoluene (b) 2 P-bromonitrobenzene (c) S 3 -hydroxybenzenesulfonid acid 15.2 Give IUPAC
The now-banned diet drug fen-phen is a mixture of two synthetic substituted benzene: fenfluramine and phentermine.
The now-banned diet drug fen-phen is a mixture of two synthetic substituted benzene: fenfluramine and phentermine. Chemists have synthesized compounds with structures similar to adrenaline, producing amphetamine.
Chapter 18: Aromatic Compounds
hapter 18: Aromatic ompounds [Sections: 18.1, 18.3-18.5, 18.8] The Structure of Benzene skeletal condensed 1800's sausage 3 2 2 3 3 3 3 Friedrich August Kekule 1829-1896 Kekule's Dream 6 6 Kekule wakes
Fundamentals of Organic Chemistry
Fundamentals of Organic Chemistry CHEM 109 For Students of Health Colleges Credit hrs.: (2+1) King Saud University College of Science, Chemistry Department CHEM 109 CHAPTER 3. AROMATIC HYDROCARBONS Aromatic
Chapter 21: Hydrocarbons Section 21.3 Alkenes and Alkynes
Section 21.1 Introduction to Hydrocarbons Section 1 Objectives: Explain the terms organic compound and organic chemistry. Section 21.2 Alkanes Chapter 21: Hydrocarbons Section 21.3 Alkenes and Alkynes
Treatment of cyclooctatetrene with potassium gives you a dianion. Classify the starting material and product as aromatic, antiaromatic or
Treatment of cyclooctatetrene with potassium gives you a dianion. Classify the starting material and product as aromatic, antiaromatic or nonaromatic? 1 2 Classify cyclononatetrene and it s various ions
240 Chem. Aromatic Compounds. Chapter 6
240 Chem Aromatic Compounds Chapter 6 1 The expressing aromatic compounds came to mean benzene and derivatives of benzene. Structure of Benzene: Resonance Description C 6 H 6 1.It contains a six-membered
CHEM 263 Notes Oct 1, Beta-carotene (depicted below) is responsible for the orange-red colour in carrots.
EM 263 otes ct 1, 2013 onjugated Dienes and olour ontinued Beta-carotene (depicted below) is responsible for the orange-red colour in carrots. In the below example, astaxanthin, a blue-green pigment in
DAMIETTA UNIVERSITY CHEM-103: BASIC ORGANIC CHEMISTRY LECTURE
DAMIETTA UNIVERSITY CHEM-103: BASIC ORGANIC CHEMISTRY LECTURE 8 Dr Ali El-Agamey Nomenclature of Benzene Derivatives Nomenclature of Benzene Derivatives To name a benzene ring with one substituent, name
Introduction to Aromaticity
Introduction to Aromaticity Historical Timeline: 1 Spotlight on Benzene: 2 Early 19 th century chemists derive benzene formula (C 6 H 6 ) and molecular mass (78). Carbon to hydrogen ratio of 1:1 suggests
KOT 222 Organic Chemistry II
KOT 222 Organic Chemistry II Course Objectives: 1) To introduce the chemistry of alcohols and ethers. 2) To study the chemistry of functional groups. 3) To learn the chemistry of aromatic compounds and
Module III: Aromatic Hydrocarbons (6 hrs)
Module III: Aromatic Hydrocarbons (6 hrs) Nomenclature and isomerism in substituted benzene. Structure and stability of benzene: Kekule, resonance and molecular orbital description. Mechanism of aromatic
CH 15: Benzene and Aromaticity. Topics: Benzene and Benzene Derivatives. Naming. Unusual Stability of Aromatics. Determining Aromaticity
rganic Chemistry otes by Jim Maxka CH 15: Benzene and Aromaticity Topics: Benzene and Benzene Derivatives aming Unusual Stability of Aromatics Determining Aromaticity ther Aromatic Species Aromaticity
Reaction mechanisms offer us insights into how reactions work / how molecules react with one another.
Introduction 1) Lewis Structures 2) Representing Organic Structures 3) Geometry and Hybridization 4) Electronegativities and Dipoles 5) Resonance Structures (a) Drawing Them (b) Rules for Resonance 6)
More Nomenclature: Common Names for Selected Aromatic Groups. Aryl = Ar = aromatic group. It is a broad term, and includes any aromatic rings.
More Nomenclature: Common Names for Selected Aromatic Groups Phenyl group = or Ph = C 6 H 5 = Aryl = Ar = aromatic group. It is a broad term, and includes any aromatic rings. Benzyl = Bn = It has a -CH
Solution problem 22: Non-Benzoid Aromatic Sytems
Solution problem 22: on-enzoid Aromatic Sytems 22.1 & 22.2 Each double bond and each heteroatom (, ) with lone pairs donates 2 π- electrons as well as a negative charge. oron or a positive charge does
CHEM 344 Molecular Modeling
CHEM 344 Molecular Modeling The Use of Computational Chemistry to Support Experimental Organic Chemistry Day 1 all calculation data obtained from Gaussian09 using B3LYP/6-31G(d) unless otherwise noted.
Terms used in UV / Visible Spectroscopy
Terms used in UV / Visible Spectroscopy Chromophore The part of a molecule responsible for imparting color, are called as chromospheres. OR The functional groups containing multiple bonds capable of absorbing
Downloaded from
1 Class XI Chemistry Ch 13: Hydrocarbons TOP Concepts: 1. Alkanes: General formula: C n H 2n+2 2. Preparation of alkanes: 3. Kolbe s electrolytic method: Alkali metal salts of carboxylic acids undergo
Chapter 13 Alkenes and Alkynes & Aromatic Compounds
Chapter 13 Alkenes and Alkynes & Aromatic Compounds Chapter Outline 13.1 Alkenes and Alkynes 13.2 Nomenclature of Alkenes and Alkynes 13.3 Cis Trans Isomers 13.4 Alkenes in Food and Medicine 13.6 Reactions
Conjugated Systems, Orbital Symmetry and UV Spectroscopy
Conjugated Systems, Orbital Symmetry and UV Spectroscopy Introduction There are several possible arrangements for a molecule which contains two double bonds (diene): Isolated: (two or more single bonds
Chemistry 11. Unit 10 Organic Chemistry Part III Unsaturated and aromatic hydrocarbons
Chemistry 11 Unit 10 Organic Chemistry Part III Unsaturated and aromatic hydrocarbons 2 1. Unsaturated hydrocarbons So far, we have studied the hydrocarbons in which atoms are connected exclusively by
Chapter 2 Alkanes and Cycloalkanes: Introduction to Hydrocarbons
Chapter 2 Alkanes and Cycloalkanes: Introduction to Hydrocarbons 2.1 Classes of Hydrocarbons Classes of Hydrocarbons Hydrocarbons only contain carbon and hydrogen atoms. Hydrocarbons are either classed
Chapter 15: Conjugated Systems, Orbital Symmetry, and UV Spectroscopy
Chapter 15: Conjugated Systems, Orbital Symmetry, and UV Spectroscopy Conjugated unsaturated systems have a p orbital on a carbon adjacent to a double bond The p orbital can come from another double (e.g.
1 TOP Concepts: Class XI Chemistry Ch 13: Hydrocarbons 1. Alkanes: General formula: C n H 2n+2 2. Preparation of alkanes: 3. Kolbe s electrolytic method: Alkali metal salts of carboxylic acids undergo
Seminar_3. 1. Substituded derivatives of benzene and their nomenclature
1. Substituded derivatives of benzene and their nomenclature 2. Reactions of arenes. Electrophilic aromatic substitutions 3. Activating substituents. Orientation in the aromatic ring Seminar_3 TEST - Aromatic
3) The delocalized π system in benzene is formed by a cyclic overlap of 6 orbitals. A) s B) p C) sp D) sp2 E) sp3
Chapter 8 Questions 1) Which of the following statements is incorrect about benzene? A) All of the carbon atoms are sp hybridized. B) It has delocalized electrons. C) The carbon-carbon bond lengths are
CHEM Review for test 1 (ch12-15). F17. Stafford
CHEM Multiple Choice Identify the choice that best completes the statement or answers the question. 1. What range of wavelengths corresponds to the infrared region of the electromagnetic spectrum? a. 200-400
Exam. Name. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which of the following statements is incorrect about benzene? 1) A) All of the carbon
Chapter 09 Benzene and Its Derivatives
Chapter 09 Benzene and Its Derivatives Benzene First isolated in 1825 from whale oil by Michael Faraday Unsaturated hydrocarbon but did not have the typical reactivity of alkenes or alkynes. CM 240: Fall
Chapter 4: Aromatic Compounds. Bitter almonds are the source of the aromatic compound benzaldehyde
Chapter 4: Aromatic Compounds Bitter almonds are the source of the aromatic compound benzaldehyde Sources of Benzene Benzene, C 6 H 6, is the parent hydrocarbon of the especially stable compounds known
16. Chemistry of Benzene: Electrophilic Aromatic Substitution. Based on McMurry s Organic Chemistry, 7 th edition
16. Chemistry of Benzene: Electrophilic Aromatic Substitution Based on McMurry s Organic Chemistry, 7 th edition Substitution Reactions of Benzene and Its Derivatives Benzene is aromatic: a cyclic conjugated
Nuggets of Knowledge for Chapter 17 Dienes and Aromaticity Chem 2320
Nuggets of Knowledge for Chapter 17 Dienes and Aromaticity Chem 2320 I. Isolated, cumulated, and conjugated dienes A diene is any compound with two or C=C's is a diene. Compounds containing more than two
followed by H 2, Ni 2 B (P-2)
Chemistry 263 omework 1 Part 2 Spring 2018 Out: 04/04/18 Due: 04/13/18 1 Value: A very generous 9 points 2 All questions are valued at ½ point per question unless otherwise noted. Name: KEY 1. Which of
Lecture 10. More Aromatics. February 18, Chemistry 328N
Lecture 10 More Aromatics February 18, 2016 eterocyclic Aromatic Compounds N N O S Pyridine Pyrrole Furan Thiophene ückel and Pyridine ückel and Pyrrole uckel and Furan Recognizing Aromatic Compounds Be
Chapter 9. Chemical Bonding II: Molecular Geometry and Bonding Theories
Chapter 9 Chemical Bonding II: Molecular Geometry and Bonding Theories Topics Molecular Geometry Molecular Geometry and Polarity Valence Bond Theory Hybridization of Atomic Orbitals Hybridization in Molecules
Organic Chemistry, 7 L. G. Wade, Jr. Chapter , Prentice Hall
Organic Chemistry, 7 th Edition L. G. Wade, Jr. Chapter 17 Reactions of Aromatic Compounds 2010, Prentice Hall Electrophilic Aromatic Substitution Although h benzene s pi electrons are in a stable aromatic
Chem 261 Dec 6, 2017
209 Chem 261 Dec 6, 2017 REVIEW: Example: K!! + 3 C + 3 C K tert-butoxide (an alkoxide) methanol tert-butanol pka = 16 pka = 19 methoxide stronger base stronger acid (lower pka, more acidic) weaker acid
Unsaturated hydrocarbons. Chapter 13
Unsaturated hydrocarbons Chapter 13 Unsaturated hydrocarbons Hydrocarbons which contain at least one C-C multiple (double or triple) bond. The multiple bond is a site for chemical reactions in these molecules.
16. Chemistry of Benzene: Electrophilic Aromatic Substitution جانشینی الکتروندوستی آروماتیک شیمی آلی 2
16. Chemistry of Benzene: Electrophilic Aromatic Substitution جانشینی الکتروندوستی آروماتیک شیمی آلی 2 Dr M. Mehrdad University of Guilan, Department of Chemistry, Rasht, Iran m-mehrdad@guilan.ac.ir Based
16. Chemistry of Benzene: Electrophilic Aromatic Substitution جانشینی الکتروندوستی آروماتیک شیمی آلی 2
16. Chemistry of Benzene: Electrophilic Aromatic Substitution جانشینی الکتروندوستی آروماتیک شیمی آلی 2 Dr M. Mehrdad University of Guilan, Department of Chemistry, Rasht, Iran m-mehrdad@guilan.ac.ir Based
Chapter 5. Aromatic Compounds
Chapter 5. Aromatic Compounds 5.1 Structure of Benzene: The Kekule Proposal Mid-1800s, benzene was known to have the molecular formula C 6 6. Benzene reacts with 2 in the presence of iron to give substitution
Practice Hour Examination # 1-1
CHEM 346 Organic Chemistry I Fall 2013 Practice Hour Examination # 1-1 Solutions Key Page 1 of 12 CHEM 346 Organic Chemistry I (for Majors) Instructor: Paul J. Bracher Practice Hour Examination # 1-1 Monday,
1. Provide a correct name for each compound below. (12 points)
Page 1 of 8 I. Nomenclature 1. Provide a correct name for each compound below. (12 points) II. Theory 1. UV spectroscopy measures the energy required to promote an electron from the molecular orbital to
Valence Bond Theory - Description
Bonding and Molecular Structure - PART 2 - Valence Bond Theory and Hybridization 1. Understand and be able to describe the Valence Bond Theory description of covalent bond formation. 2. Understand and
Learning Guide for Chapter 17 - Dienes
Learning Guide for Chapter 17 - Dienes I. Isolated, conjugated, and cumulated dienes II. Reactions involving allylic cations or radicals III. Diels-Alder Reactions IV. Aromaticity I. Isolated, Conjugated,
4. AROMATIC COMPOUNDS
BOOKS 1) Organic Chemistry Structure and Function, K. Peter C. Vollhardt, Neil Schore, 6th Edition 2) Organic Chemistry, T. W. Graham Solomons, Craig B. Fryhle 3) Organic Chemistry: A Short Course, H.
Loudon Chapter 15 Review: Dienes and Aromaticity Jacquie Richardson, CU Boulder Last updated 1/28/2019
This chapter looks at the behavior of carbon-carbon double bonds when several of them are in the same molecule. There are several possible ways they can be grouped. Conjugated dienes have a continuous
Chapter 22. Organic and Biological Molecules
Chapter 22 Organic and Biological Molecules The Bonding of Carbon Organic chemistry is the chemistry of compounds containing carbon. Because carbon can form single, double, and triple bonds, the following
EASTERN ARIZONA COLLEGE General Organic Chemistry I
EASTERN ARIZONA COLLEGE General Organic Chemistry I Course Design 2015-2016 Course Information Division Science Course Number CHM 235 (SUN# CHM 2235) Title General Organic Chemistry I Credits 4 Developed
Organic Chemistry II / CHEM 252 Chapter 13 Conjugated Unsaturated Systems
Organic Chemistry II / CHEM 252 Chapter 13 Conjugated Unsaturated Systems Bela Torok Department of Chemistry University of Massachusetts Boston Boston, MA 1 Introduction - Conjugated unsaturated systems
Class XI Chapter 13 Hydrocarbons Chemistry
Question 13.1: How do you account for the formation of ethane during chlorination of methane? Chlorination of methane proceeds via a free radical chain mechanism. The whole reaction takes place in the
Solutions a) 4-bromo-2-methylphenol b) 2-hydroxy-5-bromotoluene c) 4-bromo-1-hydroxy-2-methylbenzene OMe OH
CAPTER 18 413 R R Solutions 18.1. 3-isopropylbenzaldehyde or meta-isopropylbenzaldehyde 2-bromotoluene or ortho-bromotoluene c) 2,4-dinitrophenol d) 2-ethyl-1,4-diisopropylbenzene f) 2,6-dibromo-4-chloro-3-ethyl-5-isopropylphenol
Chapter 10. VSEPR Model: Geometries
Chapter 10 Molecular Geometry VSEPR Model: Geometries Valence Shell Electron Pair Repulsion Theory Electron pairs repel and get as far apart as possible Example: Water Four electron pairs Two bonds Two
Name Date Class HYDROCARBONS
22.1 HYDROCARBONS Section Review Objectives Describe the relationship between number of valence electrons and bonding in carbon Define and describe alkanes Relate the polarity of hydrocarbons to their
Organic Chemistry. M. R. Naimi-Jamal. Faculty of Chemistry Iran University of Science & Technology
Organic Chemistry M. R. Naimi-Jamal Faculty of Chemistry Iran University of Science & Technology Chapter 5-2. Chemistry of Benzene: Electrophilic Aromatic Substitution Based on McMurry s Organic Chemistry,
Andrew Rosen *Note: If you can rotate a molecule to have one isomer equal to another, they are both the same
*Note: If you can rotate a molecule to have one isomer equal to another, they are both the same *Note: For hybridization, if an SP 2 is made, there is one unhybridized p orbital (because p usually has
and Stereochemistry) PAPER 1: ORGANIC CHEMISTRY- I (Nature of Bonding and Stereochemistry) MODULE 4: Applications of Electronic Effects
Subject Chemistry Paper No and Title Module No and Title Module Tag Paper 1: ORGANIC - I (Nature of Bonding Module 4: Applications of Electronic Effects CHE_P1_M4 PAPER 1: ORGANIC - I (Nature of Bonding
Chapter 19: Amines. Introduction
Chapter 19: Amines Chap 19 HW: (be able to name amines); 37, 39, 41, 42, 44, 46, 47, 48, 53-55, 57, 58 Introduction Organic derivatives of ammonia. Many are biologically active. Chap 19: Amines Slide 19-2
Exam (6 pts) Show which starting materials are used to produce the following Diels-Alder products:
Exam 1 Name CHEM 212 1. (18 pts) Complete the following chemical reactions showing all major organic products; illustrate proper stereochemistry where appropriate. If no reaction occurs, indicate NR :
Amines Reading Study Problems Key Concepts and Skills Lecture Topics: Amines: structure and nomenclature
Amines Reading: Wade chapter 19, sections 19-1-19-19 Study Problems: 19-37, 19-39, 19-40, 19-41, 19-44, 19-46, 19-47, 19-48, 19-51, 19-54 Key Concepts and Skills: Explain how the basicity of amines varies
CHEM Aromatic Chemistry. LECTURE 1 - Aromaticity
1 CHEM40003 Aromatic Chemistry LECTURE 1 - Aromaticity Alan C. Spivey a.c.spivey@imperial.ac.uk May 2018 2 Format and scope of presentation Aromaticity: Historical perspective (Kekulé) Characteristics,
Chapter 13 Conjugated Unsaturated Systems
Chapter 13 Conjugated Unsaturated Systems Introduction Conjugated unsaturated systems have a p orbital on a carbon adjacent to a double bond The p orbital can come from another double or triple bond The
Chapter 15 Dienes, Resonance, and Aromaticity
Instructor Supplemental Solutions to Problems 2010 Roberts and Company Publishers Chapter 15 Dienes, Resonance, and Aromaticity Solutions to In-Text Problems 15.2 The delocalization energy is the energy
Chapter 16 Chemistry of Benzene: Electrophilic Aromatic Substitution
John E. McMurry www.cengage.com/chemistry/mcmurry Chapter 16 Chemistry of Benzene: Electrophilic Aromatic Substitution Paul D. Adams University of Arkansas Substitution Reactions of Benzene and Its Derivatives
Aliphatic Hydrocarbons Anthracite alkanes arene alkenes aromatic compounds alkyl group asymmetric carbon Alkynes benzene 1a
Aliphatic Hydrocarbons Anthracite alkanes arene alkenes aromatic compounds alkyl group asymmetric carbon Alkynes benzene 1a Hard coal, which is high in carbon content any straight-chain or branched-chain
10. Amines (text )
2009, Department of Chemistry, The University of Western Ontario 10.1 10. Amines (text 10.1 10.6) A. Structure and omenclature Amines are derivatives of ammonia (H 3 ), where one or more H atoms has been
Lecture 24 Organic Chemistry 1
CEM 232 Organic Chemistry I at Chicago Lecture 24 Organic Chemistry 1 Professor Duncan Wardrop April 6, 2010 1 Which shorthand orbital diagram best represents the LUMO of a dienophile in a Diels-Alder