Principals of Organic Chemistry مبادئ الكيمياء العضوية CHEM 230

1. Principals of Organic Chemistry مبادئ الكيمياء العضوية CHEM 230

2. معلومات عن أستاذة المقرر • الاسم : د. سوزان عبدالرحمن خياط • أستاذ الكيمياء العضوية المشارك • قسم الكيمياء • كلية العلوم (فرع الفيصلية) – جامعة الملك عبدالعزيز • غرفة رقم 314A الدور الثاني – 109 C الدور الأرضي • البريد الإلكتروني suzan122@hotmail.com saekhayyat@kau.edu.sa • الموقع الإلكتروني www.saekhayyat.kau.edu.sa

3. أهداف المقرر: يهدف المقرر إلى تعميق فهم الطالبة عن الترابط الكيميائي، تصنيف المركبات العضوية وتسميتها، والتشكل بأنواعه في المركبات العضوية، ودراسة التفاعلات العضوية الهامه لأصناف المركبات العضوية المختلفة. المحتوى العلمي للمقرر: دراسة الربط الكيميائي في المركبات العضوية من خلال نظرية التهجين - تقسيم المركبات العضوية حسب المجموعة الوظيفية - تسمية المركبات العضوية - التشكل - التفاعلات الكيميائية - المركبات الحلقية غير المتجانسة – السكريات - الأحماض الأمينية والبروتينات - التربينات -تطبيقات المركبات العضوية في الطب والزراعة والتغذية والصناعة chapter 1

4. توزيع الدرجات chapter 1

5. Main Text Book الكتاب الرئيسي المقرر “Organic Chemistry”, T. W. ,Graham Solomons & Caring B. Fryhle; 8th ed, 2007. chapter 1

6. Chapter 1BCarbon Compounds and Chemical Bonds chapter 1

7. Organic compounds are compounds that could be obtained from living organisms. Inorganic compounds are compounds that came from nonliving sources.

8. Introduction of Organic Chemistry • The chemistry of the compounds of carbon. • The human body is largely composed of organic compounds. • Organic chemistry plays a central role in medicine, bioengineering etc.

9. Common Elements in Organic Compounds

10. The structure of atom Simplified structure of an atom structure of carbon atom

11. Chemical Bonds: The Octet Rule Octet Rule • Atoms form bonds to produce the electron configuration of a noble gas (because the electronic configuration of noble gases is particularly stable). • For most atoms of interest this means achieving a valence shell configuration of 8 electrons corresponding to that of the nearest noble gas. • Atoms close to helium achieve a valence shell configuration of 2 electrons. • Atoms can form either ionic or covalent bonds to satisfy the octet rule. G. N. Lewis

12. A chemical bond is a force of attraction that holds two atoms together to fill its electron shells with 8 electrons (octet rule). Kinds of chemical bonds: • Ionic bonds • Covalent bonds • Metallic bonds chapter 1

13. IONIC BONDbond formed between two ions by the transfer of electrons

14. The Covalent Bond A covalent bondis a chemical bond formed between (nonmetal + nonmetal) or (metalloide + nonmetal) in which two or more electrons are shared by two atoms. chapter 1

15. The Covalent Bond • Covalent bonds occur between atoms of similar electronegativity(close to each other in the periodic table) • Atoms achieve octets by sharing of valence electrons • Molecules result from this covalent bonding • Valence electrons can be indicated by dots (electron-dot formula or Lewis structures) but t time-consuming • The usual way to indicate the two electrons in a bond is to use a line (one line = two electrons) chapter 1

16. The Covalent Bond Oxygen Atom Oxygen Atom Oxygen Molecule (O2) chapter 1

17. The Covalent Bond when two atoms share a pair of electrons. P+1 P+1 chapter 1

18. The Covalent Bond when two atoms share a pair of electrons. P+1 P+1 It’s like both atoms have a filled orbital. chapter 1

19. The Covalent Bond The sharing of a pair of electrons between 2 atoms. (or even 2 or 3 pairs of electrons). H2

20. The Covalent Bond The sharing of a pair of electrons between 2 atoms. Cl2

21. Covalent Bonds • Non polar covalent Bond • Atoms achieve octets by sharing of valence electrons • Molecules result from this covalent bonding • Valence electrons can be indicated by dots (electron-dot formula or Lewis structures) but this is time-consuming • The usual way to indicate the two electrons in a bond is to use a line (one line = two electrons) Chapter 1

22. F H F H 2-Polar covalent bond or polar bond is a covalent bond with greater electron density around one of the two atoms electron rich region electron poor region e- poor e- rich d+ d- 9.5

23. Orbital: a region in space where the probability of finding an electron is large • Atomic Orbitals (AOs): The region of space where one or two electrons of an isolated atom are likely to be found. • Molecular Orbitals (MOs) :The region of space where one or two electrons of a molecule are likely to be found. chapter 1

24. Bonding Molecular Orbitals (Ymolec) • AOs combine by addition (the AOs of the same phase sign overlap) • The value of Y2 (electron probability density) in the region between the two nuclei increases • The two electrons between the nuclei serve to attract the nuclei towards each other • This is the ground state (lowest energy state) of the MO chapter 1

25. Molecular Orbital of Hydrogen antibonding orbital bonding orbital chapter 1

26. The energy of electrons in the bonding orbitals is substantially less than the energy of electrons in the individual atoms • The energy of electrons in the antibonding orbitals is substantially more • In the ground state of the hydrogen molecule electrons occupy the lower energy bonding orbital only chapter 1

27. Bonding Molecular Orbital The overlapping of two hydrogen 1satomic orbitals 1s 1s Ø1 atomic orbital Ø2 atomic orbital Ψ+ = Ø1 + Ø2 bonding orbital The overlapping of two hydrogen 1swaves chapter 1

28. Antibonding molecular orbital (Y *molec) • Formed by interaction of AOs with opposite phase signs • Electrons in the antibonding orbital avoid the region between the two nuclei • Repulsive forces between the nuclei predominate and electrons in antibonding orbitals make nuclei fly apart chapter 1

29. Antibonding Molecular Orbital The overlapping of two hydrogen 1satomic orbitals 1s 1s Ψ- = Ø1 - Ø2 antibonding orbital Ø1 atomic orbital Ø2 atomic orbital The overlapping of two hydrogen 1swaves node chapter 1

30. Formation of (sigma σ)bond H2 HCl Cl2 chapter 1

31. a) Sigma bond formation by s – s overlap Diagram of sigma bond formation by s – s overlap chapter 1

32. b) Sigma bond formation by s – p overlap Diagram of sigma bond formation by s – p overlap chapter 1

33. c) Sigma bond formation by p – p overlap Energy Diagram of sigma bond formation by p – p overlap chapter 1

34. Formation of (pi π)bond chapter 1

35. Structural Theory Central Premises • Valency: atoms in organic compounds form a fixed number of bonds. • Carbon can form one or more bonds to other carbons.

36. The Structure of Methane and Ethane: sp3 Hybridization • The structure of methane with its four identical tetrahedral bonds cannot be adequately explained using the electronic configuration of carbon • Hybridization of the valence orbitals (2s and 2p) provides four new identical orbitals which can be used for the bonding in methane • Orbital hybridization is a mathematical combination of the 2s and 2p wave functions to obtain wave functions for the new orbitals chapter 1

37. When one 2s orbital and three 2p orbitals are hybridized four new and identical sp3 orbitals are obtained • When four orbitals are hybridized, four orbitals must result • Each new orbital has one part s character and 3 parts p character • The four identical orbitals are oriented in a tetrahedral arrangements • The antibonding orbitals are not derived in the following diagram • The four sp3 orbitals are then combined with the 1s orbitals of four hydrogens to give the molecular orbitals of methane • Each new molecular orbital can accommodate 2 electrons chapter 1

38. sp3 hybridization in Methane CH4 excitation becomes Ground state excited state chapter 1

39. chapter 1

40. A variety of representations of methane show its tetrahedral nature and electron distribution • a. calculated electron density surface b. ball-and-stick model c. a typical 3-dimensional drawing chapter 1

41. Molecule geometry of CH4 4 sp3 hybrid orbitals 10.4

42. Ethane (C2H6) • The carbon-carbon bond is made from overlap of two sp3 orbitals to form a s bond • The molecule is approximately tetrahedral around each carbon chapter 1

43. The representations of ethane show the tetrahedral arrangement around each carbon • a. calculated electron density surface b. ball-and-stick model c. typical 3-dimensional drawing Generally there is relatively free rotation about s bonds • Very little energy (13-26 kcal/mol) is required to rotate around the carbon-carbon bond of ethane chapter 1

44. Examples of Sigma Bond Formation

45. The Structure of Ethene (Ethylene) : sp2Hybridization • Ethene (C2H2) contains a carbon-carbon double bond and is in the class of organic compounds called alkenes • Another example of the alkenes is propene • The geometry around each carbon is called trigonal planar • All atoms directly connected to each carbon are in a plane • The bonds point towards the corners of a regular triangle • The bond angle are approximately 120o chapter 1

46. The C—C s Bond in Ethane In-phase overlap of half-filled sp3 hybridorbital of one carbon with half-filled sp3hybrid orbital of another. Overlap is along internuclear axis to give a s bond.

47. The C—C s Bond in Ethane In-phase overlap of half-filled sp3 hybridorbital of one carbon with half-filled sp3hybrid orbital of another. Overlap is along internuclear axis to give a s bond.

48. hybrid orbitals – sp, sp2, or sp3

49. hybrid orbitals – sp, sp2, or sp3