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1、., 2011 Pearson Education, Inc.,Organic Chemistry 6th Edition Paula Yurkanis Bruice,Chapter 1 Electronic Structure and Bonding Acids and Bases,., 2011 Pearson Education, Inc.,Carbon-containing compounds were once considered “organ compounds” available only from living organisms. The synthesis of the
2、 simple organic compound urea 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.,Carbon neither gives up nor accepts electrons
3、 because it is in the center 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.,Why
4、 Study Organic Chemistry?,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
5、. Admission into these professional programs is highly dependent on your performance in Organic Chemistry.,.,5,Examples of Organic Compounds Used as Drugs,Methotrexate, Anticancer Drug,5-Fluorouracil, Colon Cancer Drug,Tamiflu, Influenza Drug,AZT, HIV Drug,.,6,Examples of Organic Compounds Used as D
6、rugs,Haldol, Antipsychotic,Elavil, Antidepressant,Prozac, Antidepressant,Viagra, TreatsErectile Dysfunction,., 2011 Pearson Education, Inc.,The Structure of an Atom,., 2011 Pearson Education, Inc.,The Distribution of Electrons in an Atom,Quantum mechanics uses the mathematical equation of wave motio
7、ns to characterize 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.,., 2011 Pearson Education, Inc.,The ground-state elect
8、ronic configuration describes the orbitals occupied by the atoms electrons with the lowest energy,., 2011 Pearson Education, Inc.,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 orbi
9、tal 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.,Lewiss theory: an atom will give up, accept, or share el
10、ectrons in order to achieve a filled outer shell or an outer shell that contains eight electrons,., 2011 Pearson Education, Inc.,Ionic Bonds Are Formed by the Transfer of Electrons,Attractive forces between opposite charges are called electrostatic attractions,., 2011 Pearson Education, Inc.,Covalen
11、t Bonds Are Formed by Sharing Electrons,., 2011 Pearson Education, Inc.,., 2011 Pearson Education, Inc.,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 Education, Inc.,A
12、polar covalent bond has a slight positive charge on one end and a slight negative charge on the other,., 2011 Pearson Education, Inc.,., 2011 Pearson Education, Inc.,A Polar Bond Has a Dipole Moment,A polar bond has a negative end and a positive end,dipole moment (D) = m = e x d,., 2011 Pearson Educ
13、ation, Inc.,Electrostatic Potential Maps,., 2011 Pearson Education, Inc.,Lewis Structure,Formal charge = number of valence electrons (number of lone pair electrons +1/2 number of bonding electrons),., 2011 Pearson Education, Inc.,Nitrogen has five valence electrons,Carbon has four valence electrons,
14、Hydrogen has one valence electron and halogen has seven,., 2011 Pearson Education, Inc.,Important Bond Numbers,Neutral,Cationic,Anionic,.,24,Non-Octet Species,., 2011 Pearson Education, Inc.,., 2011 Pearson Education, Inc.,The s Orbitals,An orbital tells us the volume of space around the nucleus whe
15、re an electron is most likely to be found,., 2011 Pearson Education, Inc.,The p Orbitals,., 2011 Pearson Education, Inc.,Molecular Orbitals,Molecular orbitals belong to the whole molecule.,s bond: formed by overlapping of two s orbitals.,Bond strength/bond dissociation: energy required to break a bo
16、nd or energy released to form a bond.,., 2011 Pearson Education, Inc.,., 2011 Pearson Education, Inc.,In-phase overlap forms a bonding MO; out-of-phase overlap forms an antibonding MO:,., 2011 Pearson Education, Inc.,Sigma bond (s) is formed by end-on overlap of two p orbitals:,A s bond is stronger than a p bond,., 2011 Pearson Education, Inc.,Pi bond (p) is formed by sideways overlap of two parallel p orbitals:,., 2011 Pearson Education, Inc.,Bonding in Methane,., 2011 Pe
