Carbon Allotropes: Graphite Carbon Allotropes: Graphene Carbon Allotropes

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1 What is Organic Chemistry? Wikipedia definition: "Organic chemistry is a discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds that contain carbon.” Carbon is the third most abundant element in the universe after hydrogen and oxygen respectively. Pure carbon is an allotrope, i.e., in its crystalline state it can exist in different forms with different atomic arrangements and different physical/chemical properties. Some of the allotropic forms of carbon are: graphite, graphene, fullerene and diamond. Graphite is layered. In each layer, the carbon atoms are arranged in a hexagonal lattice. Carbon Allotropes: Graphite Graphite is commonly used in “lead” pencils, which is a misnomer. http://wikipedia.org •Graphene is a one-atom-thick planar sheet of sp2-bonded carbon atoms that are in a hexagonal arrangement in a honeycomb crystal lattice. •The bond length in graphene is 0.142 nm. •It behaves as a semi-metal and semiconductor. •It is presently one of the most expensive materials on Earth. A sample the size of a cross section of a human hair has a cost of more than $1,000. vs. graphite Carbon Allotropes: Graphene http://wikipedia.org •Truncated icosahedron •Twenty hexagons and twelve pentagons •The 6:6 ring bonds (between two hexagons) can be considered "double bonds" and are shorter than the 6:5 bonds (between a hexagon and a pentagon). Their average bond length is 0.148 nm. Carbon Allotropes: Buckminsterfullerene (IUPAC name (C60-Ih)[5,6]fullerene) http://wikipedia.org •Transparent crystal of tetrahedral sp3 hybridized carbon atoms with bond lengths > 0.148 nm •Crystal lattice is a variation of a face centered cubic structure •Formed at high-pressure and high-temperature •Hardest material known, slows light traveling in a vacuum by 40% Carbon Allotropes: Diamond http://wikipedia.org

Transcript of Carbon Allotropes: Graphite Carbon Allotropes: Graphene Carbon Allotropes

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•  What is Organic Chemistry? ❏  Wikipedia definition: "Organic chemistry is a discipline within chemistry which

involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds that contain carbon.”

❏  Carbon is the third most abundant element in the universe after hydrogen and oxygen respectively. ❏  Pure carbon is an allotrope, i.e., in its crystalline state it can exist in different forms with different atomic arrangements and different physical/chemical properties. ❏  Some of the allotropic forms of carbon are: graphite, graphene, fullerene and diamond.

Graphite is layered. In each layer, the carbon atoms are arranged in a hexagonal lattice.

Carbon Allotropes: Graphite

Graphite is commonly used in “lead” pencils, which is a misnomer.

http://wikipedia.org

• Graphene is a one-atom-thick planar sheet of sp2-bonded carbon atoms that are in a hexagonal arrangement in a honeycomb crystal lattice. • The bond length in graphene is ≅ 0.142 nm. • It behaves as a semi-metal and semiconductor. • It is presently one of the most expensive materials on Earth. A sample the size of a cross section of a human hair has a cost of more than $1,000.

vs. graphite

Carbon Allotropes: Graphene

http://wikipedia.org

• Truncated icosahedron • Twenty hexagons and twelve pentagons • The 6:6 ring bonds (between two hexagons) can be considered "double bonds" and are shorter than the 6:5 bonds (between a hexagon and a pentagon). Their average bond length is ≅ 0.148 nm.

Carbon Allotropes: Buckminsterfullerene (IUPAC name (C60-Ih)[5,6]fullerene)

http://wikipedia.org

• Transparent crystal of tetrahedral sp3 hybridized carbon atoms with bond lengths > 0.148 nm • Crystal lattice is a variation of a face centered cubic structure • Formed at high-pressure and high-temperature • Hardest material known, slows light traveling in a vacuum by ≅ 40%

Carbon Allotropes: Diamond

http://wikipedia.org

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Organic Chemistry ❏  …….. is a discipline within chemistry which involves the

scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds that contain carbon.

1. Approximately how many compounds that contain carbon have been published in the scientific literature to date?

A. 100,000 B. 1,000,000 C. 10,000,000 D. 100,000,000 E. 1,000,000,000

2.  How many different arrangements of carbon & hydrogen atoms (framework patterns/structural backbones/ shapes) are found in the published organic molecules?

A. 100 B. 1,000 C. 10,000 D. 100,000 E. 1,000,000

The names of many organic molecules tend to be unique.

http://www.chm.bris.ac.uk/sillymolecules/sillymols.htm

3. How many different single and multi-step reactions have been published?

A. 100 B. 1,000 C. 10,000 D. 100,000 E. 1,000,000

4. What is the general stoichiometry (mole ratios of a and b respectively) of the reactants A & B in > 95% of all organic reactions?

aA + bB → product(s)

A. 2:1 B. 3:2 C. 1:1 D. No idea.

5. How old is organic chemistry as a science?

A.  5,000 years old B.  1,000 years old C.  500 years old D.  200 years old E.  50 years old

How old is organic chemistry as a science? ❏  Separation & Purification: distillation, recrystallization,

chromatography (3000 B.C. to present) ❏  Ancient view: "Living = Organic" vs. Inanimate = Inorganic ❏  Urea, Vitalism & Friedrich Wohler, Ann. Physik: 122, 253

(1828) ❏  Formulas & "Functionality", Wurtz (1849) ❏  Synthesis: Kolbe [alcohols], Williamson [ethers], Baeyer

[aspirin], (1850) ❏  Kekule's Snake (1857-58) ❏  Graphic Formulas (Couper, Butlerov; 1861) ❏  Lewis Structures /G.N. Lewis, J. Amer. Chem. Soc., 38, 762

(1916) ❏  Spectroscopy: IR, UV, NMR, MS, (1920 to present)

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6. Which undergraduate majors other than chemistry and chemical engineering require undergraduate courses in O-Chem?

❏  Pre-med, biological, plant, animal, life, forensics, and some environmental & “non-science” majors.

❏  Any of you psychology majors? ❏  Middle/ secondary education majors?

7. Where does Organic Chemistry fit in your career plans, and how can you usefully apply the knowledge that you develop?

❏  Only you can answer these questions. 8. What do you plan to do in this course to meet your goals and

expectations? ❏  Only you can answer this question. ❏  Memorize, memorize, memorize….??

~24,000,000 compounds ~800,000 different shapes ~14,000,000 reactions

Not a good idea?

What do you need to do in this course to meet Dr. R.’s expectations? (Are his different than mine?)

Dr. R.’s: Have a clear understanding of and be able to apply fundamental concepts./ Master hands-on skills. / Score well in tests.

Laboratory: 1.  Develop safe, efficient, and hygienic operational skills; 2.  Provide unambiguous, succinct, and clear records (lab notebook)

and personal communications (written & oral reports) 3.  Deliver products (compounds in vials: synthetic, isolated,

purified); 4.  Demonstrate an understanding of the relationship of the “real”

world of hands-on chemical handling & reactions to theoretical notions of molecules, structures. (A most important bridge with class lectures.)

Pre-class / In-class / Tests: 1.  Prepare before each class by consulting the on-line presentation

links from the course calendar Web page, preview the corresponding sections in the Carey textbook, prepare answers to the embedded questions. (These will be used with your i-clicker during each class.) Come to every class.

2.  Practice using the key concepts as soon as possible after the material is covered by working on the Webassign questions (individually), Worksheets (collaboratively), and ACS questions (individually and collaboratively); stay current with new information and concepts with practice on a daily basis.

3.  Keep information simple and memorization to a minimum; trust your logic; find useful metaphors; focus on molecular patterns. Your understanding & confidence will build, and it will be easier than cramming before test day. Learn to take tests.

Important General Chemistry Topics: (Many of these MUST be mastered.) Atomic & Molecular Structure

•  Carbon, Hydrogen, Nitrogen, Oxygen (Sulfur, Phosphorus and the Halogens)

•  Electron Configurations / Atomic s and p Orbitals •  Octets, Expanded Octets •  Molecular Orbitals •  Hybridization/ Molecular Shape •  Forces between atoms / Ionic & Covalent Bonding / Lewis

Structures (Bonded / Non-bonded electrons) •  Using the Periodic Table / Atomic Size, electronegativity, valence,

& other properties •  Bond Types / Covalent; Ionic; Hydrogen; Others

General Chemistry Topics: (To be expanded and thoroughly covered.) Atomic & Molecular Structure •  Empirical & Molecular Formulas •  Structural Formulas •  Lewis or Bond Line •  Condensed •  Line or Line-Angle or Skeletal or Stick or Wire •  3-dimensional (VSEPR)

•  Resonance •  Polarity & Formal Charge •  Organic Functions

http://chemconnections.org/COT/organic1/VSEPR/

General Chemistry Topics: (To be expanded and thoroughly covered.) Acids & Bases

•  Definitions: Arrhenius, Brønsted, Lewis •  Organic Acids & Bases •  Strength, pH, pKa, pKb / Relative Strengths

•  Reactivity

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http://chemconnections.org/organic/Movies%20Organic/Representations.mov http://chemconnections.org/COT/organic1/VSEPR/2B-jmol.html

1920

1920 1920

1930 - 1996

What is bombykol’s molar mass?

http://www.senseofsmell.org/scientific-articles-pheromones.php

http://www.3dchem.com/molecules.asp?ID=34 http://www.3dchem.com/molecules.asp?ID=305

http://upload.wikimedia.org/wikipedia/commons/7/73/TwinPeaksDepthAdjusted.jpg

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http://www.3dchem.com/molecules.asp?ID=305

Taxus baccata

Taxotere (docetaxel)

Cancer chemotherapy (~$2bn/yr)

Molecular Shapes? http://www.personal.kent.edu/~cearley/PChem/jmol/collagen.htm

Protein Shape: Forces, Bonds, Self Assembly, Folding

10-40kJ/mol

700-4,000kJ/mol

150-1000kJ/mol

0.05-40kJ/mol

Ion-dipole (Dissolving) 40-600kJ/mol

Streptococcus pyogenes 96,000 x

Vincent A. Fischetti Ph.D., Rockefeller University http://chemconnections.org/Presentations/Columbia/slide8-3.html

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Returning to a very important question. What do you plan to do in this course to meet your goals and

expectations? (Self Perceived Abilities) A) not that much; I'm very "smart" with an IQ > 140; chemistry & science

come easily to me. B) lots and lots since I'm not as "smart" as I would like to be, and chemistry is a

real challenge to me. C) enough to develop solid skills by practicing everyday. D) cram, cram, cram before each quiz, exam, and the final. E) more than one of the above.

Self-perceived abilities (SPA), motivation and self-confidence ~50% nature ~50% nuture: Psychological Science (May 2009)

Practice is more important than natural abilities: Intelligence (September 2007)

12719419112001

Ritalin

β-Blocker

MDMA

Provigil Pain Relief

Learning styles and study approaches to Organic Chemistry: http://chemconnections.org/organic/chem226/Labs/learning.html

Syllabus/Course Homepage: http://chemconnections.org/organic/chem226/