Introduction and Chapter1

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1 rganic Chemistry Classification of Chemistry Physical Chemistry Inorganic Chemistry Analytical Chemistry rganic Chemistry Definition of rganic Chemistry the chemistry of the carbon compounds stable covalent bonds to other carbon atoms as well as to heteroatoms (, N, S, P, X, etc.) exceptions: C, C 2, Na 2 C 3, etc. rgchem1-intro&chap1 1

2 Death of the Vital Force Theory The Vital Force Theory 1. nly a living organism can make an organic compound 2. rganic compounds obtained from living organisms still contained some of the force of the organism that made them (vitamin C, saponin, etc.) Evidences against the Vital Force Theory 1. Laboratory synthesis of urea from ammonium cyanate: F. Wöhler, Lab synthesis of acetic acid (H. Kolbe, 1844), formic acid & methane from C (M. Berthelot, 1860) 3. Fermentation from yeast extracts, free of living cells: E. Büchner, 1897 (Nobel Prize in 1907) rgchem1-intro&chap1 2

3 Why study rganic Chemistry? Indispensable to many fields of science and technology Petrochemicals Agrochemicals Dyes & Pigments Food (Additives) Biology & Biochemistry Display materials and so on.. Pharmaceuticals (Bio)Polymers Cosmetics Household products Electrochemicals rganic electronics rgchem1-intro&chap1 3

4 Petrochemicals + H + cat. cumene 2 H + H 3 + H phenol acetone cumene hydroperoxide rgchem1-intro&chap1 4

5 Pharmaceuticals & Medicinal Chemistry H H H 1. HN 3 Ac 2 2. Pd, H 2 NH 2 NHAc Tylenol RCNH N S C 2 H R = PhCH 2 ; Pen G R = PhCH(NH 2 ); ampicillin R = (4-H)-PhCH(CH2); amoxycillin rgchem1-intro&chap1 5

6 Agrochemicals H 1. Lindlar, H 2 1. mcpba Me H Aldrich, $20.0/500g 2. acetone, H + 2. Me 2 CuLi H 1. HCl 2. TsCl, py 3. NaI H H H + multistriatin: a pheromone of the elm bark beetle H H 3-pentanone LDA I Me H rgchem1-intro&chap1 6

7 Polymers & Biopolymers Me 2 C C 2 Me + HCH 2 CH 2 H - MeH 2 C C 2 CH 2 CH 2 polyester (Dacron) n H H NH H Ac(H) H NH H Ac(H) H NH Ac(H) chitin (chitosan) rgchem1-intro&chap1 7

8 Biology & Biochemistry 11 H 2 N opsin -H 2 11-cis-retinal CH retinal isomerase hν H 2 nerve pulse N + opsin H vitamin A (retinol) retinol dehydrogenase all-trans-retinal CH rgchem1-intro&chap1 8

9 Electrochemicals ethylene carbonate (better electrolyte) THF (poor electrolyte) rgchem1-intro&chap1 9

10 Display Materials * n * polyacetylene * n PPP * * N n * H polypyrrole * n * * S n * PPV polythiophene rgchem1-intro&chap1 10

11 Targets of rganic Chemistry I & II Reactions rganic Compounds Structure: bonding (analysis) Mechanism rgchem1-intro&chap1 11

12 그저익숙하도록읽는것뿐이다. 글을읽는사람이, 비록글의뜻은알았으나, 만약익숙하지못하면읽자마자곧잊어버리게되어, 마음에간직할수없을것은틀림없다. 이미읽고난뒤에, 또거기에자세하고익숙해질공부를더한뒤라야비로소마음에간직할수있으며, 또흐뭇한맛도있을것이다. - 퇴계이황 ( 금장태著 ) rgchem1-intro&chap1 12

13 Chapter 1. A Simple Model for Structure What to master Draw Lewis structures Determine formal charges Estimate stabilities of structures Understand and draw resonance structures Identify polar bonds and determine polarities Determine shapes of molecules Determine dipole moments of molecules rgchem1-intro&chap1 13

14 Simple Models for Structure Simple atomic structure: Lewis structure valence electrons Br Se Ca 3, Figure 1.1 Simple Molecular Bonding Models stabilizing effect gained by filling outer shell of electrons: the octet rule (a noble gas configuration) 1. Ionic bonding: between ions with opposite charges a high-melting solid; 4 Figure Covalent bonding: sharing electrons between atoms; 5 due to unstable high charge/volume ratio weak intermolecular bonding: lower boiling point rgchem1-intro&chap1 14

15 Simple Models for Molecular Bonding (I) Lewis structure for molecules: H 2 ; 6 Figure 1.3 common number of bonds formed: 7 Table 1.1 exceptions: the 3rd and subsequent periods of elements determination of stability: 8 top & Problem 1.5 writing a Lewis structure: 9-10; CH 4 Figure 1.4, C 2 H & HCN 1.6 Covalent ions: ions composed of covalent bonds calculation of charges: 11 top 1. Counting No. of (protons - electrons) N: = +1, Cl: 7-8 = Balancing the charges N: (H) = +1, Cl: 0-1 (H) = -1 rgchem1-intro&chap1 15

16 rgchem1-intro&chap1 16

17 Simple Models for Molecular Bonding (II) Formal charge: covalent molecules; Fig approximate charge distribution among the atoms each atom: valence e - - unshared e - - (shared e - )/2 total charge of a molecule: sum of the formal charges on all the atoms of a molecule: 13, Practice 1.3 refined estimate of stability of molecules: HCN 14 middle & Problem 1.9: 14 bottom Resonance: CH 3 N 2 ; 15-16, Figure when any Lewis structure can not represent a real molecule, the actual structure is a resonance hybrid resonance (stabilization) energy & arrow change only the positions of unshared e - & multiple bonds rgchem1-intro&chap1 17

18 Simple Models for Molecular Bonding (III) Polar (covalent) bonds: H Cl H Cl atoms of much different electronegativities; 17 Table 1.2 affects physical properties & chemical reactions dipole moment (µ) = (charge amount) x (distance) molecular dipole: Σ individual bond dipoles, 3-D structure Shapes of molecules δ + δ - VSEPR (valence shell electron pair repulsion) theory: Rule 1: 19 top; 19 Figure 1.11 Rule 2: 20 middle; 21, Figure 1.13 Rule 3: 20 bottom; 21, Figure 1.14 Molecular dipole moments: 23, Figure 1.15 rgchem1-intro&chap1 18

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Leaflet-chemistry-chem-chris suen 2016.xdw 香港中學文憑試 HKDSE ( 補習課程中四年級至中六年級 ) MSc, BSc (Hons) HKU, PGDE HKU 導師簡介 : 一級學府畢業, 專業教師資格, 名校生補習之選全港唯一主修分析化學碩士級名師 * 畢業於香港一級學府香港大學化學系, 獲榮譽