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1、,Organic Chemistry 6th Edition Paula Yurkanis Bruice,Chapter 1 Electronic Structure and Bonding Acids and Bases, 2011 Pearson Education, Inc.,相关知识,Carbon-containing compounds were once considered “organ compounds” available only from living organisms. The synthesis of the simple organic compound ure
2、a in 1828 showed that organic compounds can be prepared in the laboratory from non-living material. Today, organic natural products are routinely synthesized in the laboratory.,Organic Chemistry, 2011 Pearson Education, Inc.,相关知识,Carbon neither gives up nor accepts electrons because it is in the cen
3、ter of the second periodic row. Consequently, carbon forms bonds with other carbons and other atoms by sharing electrons. The capacity of carbon to form bonds in this fashion makes it the building block of all living organisms.,Why Carbon?, 2011 Pearson Education, Inc.,相关知识,Why Study Organic Chemist
4、ry?,Since carbon is the building block of all living organisms, a knowledge of Organic Chemistry is a prerequisite to understanding Biochemistry, Medicinal Chemistry, and Pharmacology. Indeed, Organic Chemistry is a required course for studying Pharmacy, Medicine, and Dentistry. Admission into these
5、 professional programs is highly dependent on your performance in Organic Chemistry., 2011 Pearson Education, Inc.,相关知识,Examples of Organic Compounds Used as Drugs,Methotrexate, Anticancer Drug,5-Fluorouracil, Colon Cancer Drug,Tamiflu, Influenza Drug,AZT, HIV Drug,5,相关知识,Examples of Organic Compoun
6、ds Used as Drugs,Haldol, Antipsychotic,Elavil, Antidepressant,Prozac, Antidepressant,Viagra, TreatsErectile Dysfunction,6,相关知识,The Structure of an Atom, 2011 Pearson Education, Inc.,相关知识,The Distribution of Electrons in an Atom,Quantum mechanics uses the mathematical equation of wave motions to char
7、acterize the motion of an electron around a nucleus.,Wave functions or orbitals tell us the energy of the electron and the volume of space around the nucleus where an electron is most likely to be found., 2011 Pearson Education, Inc.,相关知识, 2011 Pearson Education, Inc.,相关知识,The ground-state electroni
8、c configuration describes the orbitals occupied by the atoms electrons with the lowest energy, 2011 Pearson Education, Inc.,相关知识,The Aufbau principle: an electron always goes to the available orbital with the lowest energy,The Pauli exclusion principle: only two electrons can occupy one atomic orbit
9、al and the two electrons have opposite spin,Hunds rule: electrons will occupy empty degenerated orbitals before pairing up in the same orbital,The following principles determine which orbitals electrons occupy:, 2011 Pearson Education, Inc.,相关知识,Lewiss theory: an atom will give up, accept, or share
10、electrons in order to achieve a filled outer shell or an outer shell that contains eight electrons, 2011 Pearson Education, Inc.,相关知识,Ionic Bonds Are Formed by the Transfer of Electrons,Attractive forces between opposite charges are called electrostatic attractions, 2011 Pearson Education, Inc.,相关知识
11、,Covalent Bonds Are Formed by Sharing Electrons, 2011 Pearson Education, Inc.,相关知识, 2011 Pearson Education, Inc.,相关知识,Equal sharing of electrons: nonpolar covalent bond (e.g., H2),Sharing of electrons between atoms of different electronegativities: polar covalent bond (e.g., HF), 2011 Pearson Educat
12、ion, Inc.,相关知识,A polar covalent bond has a slight positive charge on one end and a slight negative charge on the other, 2011 Pearson Education, Inc.,相关知识, 2011 Pearson Education, Inc.,相关知识,A Polar Bond Has a Dipole Moment,A polar bond has a negative end and a positive end,dipole moment (D) = m = e x
13、 d, 2011 Pearson Education, Inc.,相关知识,Electrostatic Potential Maps, 2011 Pearson Education, Inc.,相关知识,Lewis Structure,Formal charge = number of valence electrons (number of lone pair electrons +1/2 number of bonding electrons), 2011 Pearson Education, Inc.,相关知识,Nitrogen has five valence electrons,Ca
14、rbon has four valence electrons,Hydrogen has one valence electron and halogen has seven, 2011 Pearson Education, Inc.,相关知识,Important Bond Numbers,Neutral,Cationic,Anionic, 2011 Pearson Education, Inc.,相关知识,Non-Octet Species,24,相关知识, 2011 Pearson Education, Inc.,相关知识,The s Orbitals,An orbital tells u
15、s the volume of space around the nucleus where an electron is most likely to be found, 2011 Pearson Education, Inc.,相关知识,The p Orbitals, 2011 Pearson Education, Inc.,相关知识,Molecular Orbitals,Molecular orbitals belong to the whole molecule.,s bond: formed by overlapping of two s orbitals.,Bond strengt
16、h/bond dissociation: energy required to break a bond or energy released to form a bond., 2011 Pearson Education, Inc.,相关知识, 2011 Pearson Education, Inc.,相关知识,In-phase overlap forms a bonding MO; out-of-phase overlap forms an antibonding MO:, 2011 Pearson Education, Inc.,相关知识,Sigma bond (s) is formed
17、 by end-on overlap of two p orbitals:,A s bond is stronger than a p bond, 2011 Pearson Education, Inc.,相关知识,Pi bond (p) is formed by sideways overlap of two parallel p orbitals:, 2011 Pearson Education, Inc.,相关知识,Bonding in Methane, 2011 Pearson Education, Inc.,相关知识,Hybridization of One s and Three
18、p Orbitals, 2011 Pearson Education, Inc.,相关知识,The orbitals used in bond formation determine the bond angles,Tetrahedral bond angle: 109.5,Electron pairs spread themselves into space as far from each other as possible, 2011 Pearson Education, Inc.,相关知识,The Bonds in Ethane, 2011 Pearson Education, Inc
19、.,相关知识,Hybrid Orbitals of Ethane, 2011 Pearson Education, Inc.,相关知识,Bonding in Ethene: A Double Bond, 2011 Pearson Education, Inc.,相关知识,Bonding in Ethyne: A Triple Bond, 2011 Pearson Education, Inc.,相关知识,Bonding in the Methyl Cation, 2011 Pearson Education, Inc.,相关知识,Bonding in the Methyl Radical, 2
20、011 Pearson Education, Inc.,相关知识,Bonding in the Methyl Anion, 2011 Pearson Education, Inc.,相关知识,Bonding in Water, 2011 Pearson Education, Inc.,相关知识,Bonding in Ammonia and in the Ammonium Ion, 2011 Pearson Education, Inc.,相关知识,Bonding in Hydrogen Halides, 2011 Pearson Education, Inc.,相关知识,Summary,The
21、 shorter the bond, the stronger it is,The greater the electron density in the region of orbital overlap, the stronger is the bond,The more s character, the shorter and stronger is the bond,The more s character, the larger is the bond angle, 2011 Pearson Education, Inc.,相关知识,The vector sum of the mag
22、nitude and the direction of the individual bond dipole determines the overall dipole moment of a molecule,Molecular Dipole Moment, 2011 Pearson Education, Inc.,相关知识,BrnstedLowry Acids and Bases, 2011 Pearson Education, Inc.,相关知识,An Acid/Base Equilibrium,Ka: The acid dissociation constant.,The strong
23、er the acid, the larger its Ka value and the smaller its pKa value., 2011 Pearson Education, Inc.,相关知识,The Most Common Organic Acids Are Carboxylic Acids, 2011 Pearson Education, Inc.,相关知识, 2011 Pearson Education, Inc.,相关知识,Protonated alcohols and protonated carboxylic acids are very strong acids, 2
24、011 Pearson Education, Inc.,相关知识,An amine can behave as an acid or as a base, 2011 Pearson Education, Inc.,相关知识, 2011 Pearson Education, Inc.,相关知识,Strong Acids / Bases React to Form Weak Acids / Bases, 2011 Pearson Education, Inc.,相关知识,The Structure of an Acid Affects Its Acidity,The weaker the base
25、, the stronger is its conjugate acid,Stable bases are weak bases,The more stable the base, the stronger is its conjugate acid, 2011 Pearson Education, Inc.,相关知识,The stability of a base is affected by its size and its electronegativity, 2011 Pearson Education, Inc.,相关知识, 2011 Pearson Education, Inc.,
26、相关知识,When atoms are very different in size, the stronger acid will have its proton attached to the largest atom,size overrides electronegativity, 2011 Pearson Education, Inc.,相关知识,When atoms are similar in size, the stronger acid will have its proton attached to the more electronegative atom, 2011 P
27、earson Education, Inc.,相关知识,Substituents Affect the Strength of an Acid, 2011 Pearson Education, Inc.,相关知识,Inductive electron withdrawal increases the acidity of a conjugate acid, 2011 Pearson Education, Inc.,相关知识,Acetic acid is more acidic than ethanol,The delocalized electrons in acetic acid are s
28、hared by more than two atoms, thereby stabilizing the conjugated base, 2011 Pearson Education, Inc.,相关知识,A Summary of the Factors That Determine Acid Strength,Size: As the atom attached to the hydrogen increases in size, the strength of the acid increases,2. Electronegativity, 2011 Pearson Education
29、, Inc.,相关知识,3. Hybridization,4. Inductive effect, 2011 Pearson Education, Inc.,相关知识,5. Electron delocalization, 2011 Pearson Education, Inc.,相关知识,Lewis Acids and Bases, 2011 Pearson Education, Inc.,相关知识,Basicity and Drug Design: Methotrexate, Substituting Nitrogen for Oxygen,68,相关知识,Acidity and Cosmetics: Skin Peel Agents,Skin Peels: Remove old skin with an acid to expose new young-looking skin. The stronger the acid, the deeper the peel. Examples of skin peel agents:,69,相关知识,