Organic Chemistry Flashcards
Organic chemistry
The branch of chemistry that studies carbon compounds.
C-C & C-H bonds
C-C & C-H bonds are strong and non-polar making them unreactive.
Functional groups
A group of atoms that determines how an organic molecule functions/reacts. A site of reactivity. (Ex: C-O, C-N)
Hydrocarbons
Alkanes = (sigma), Alkenes = (sigma + pi), Alkynes = (sigma + 2pi), Aromatics = (sigma + delocalized pi)
Non-Cyclic Alkanes
C(n)H(2n+2), contain only single covalent bonds between carbon atoms. Melting, boiling point and # of isomers of alkanes increases as (n) increases. All sp^3 (tetrahedral), named by longest chain & position of groups - list substituents in alphabetical order.
Structural Isomers
Compounds with the same molecular formula but different bonding arrangements. Have somewhat different physical and chemical properties.
Cycloalkanes
Alkanes can form ringed structures of 3, 4, 5, 6 etc. carbons. 5 & 6 (cyclopentane, cyclohexane) are the most stable. They can take on conformation in which angels are nearly tetrahedral, but the smaller rings (cyclobutane, cyclopropane) are strained and reactive. SINGLE BONDS ONLY.
Alkane reactivity
Rather unreactive due to presence of only C-C and C-H (sigma) non-polar bonds. Used as non-polar solvents and fuels (methane) since combustion is exothermic.
Combustion rx.
CH(4)(g) + 2O(2)(g) -> CO(2)(g) + 2H(2)O(g)
Alkenes
Unsaturated (fewer than max # of hydrogens) hydrocarbons that contain C and H atoms and at least on C=C double bond. Location of double bond is indicated by a prefix, chain #ed so double bond gets smallest possible #. Cannot rotate freely about the double bond due to unhybridized (pi) bond. No rotation means geometric isomers are possible (cis and trans). Double bonds are sp^2 hybridized (trigonal planar).
Cis and Trans Isomers
Geometric isomers on double bonds. Cis = “this side of”, substituents are on same sides of double bond. Trans = “other side of”, substituents are on opposite side of double bond.
Alkynes
Unsaturated hydrocarbons that contain at least one C-C TRIPLE bond. They are sp (linear) hybridized. Location of triple bond is indicated by a prefix, chain #ed so triple bond gets smallest possible #.
Addition reactions
Dominate reactions in alkenes and alkynes. R(2)C=CR(2) + X(2) -> R(2)XC-CXR(2), where X(2) = H(2), Br(2) etc.
Aromatic Hydrocarbons
Formally related to benzene C(6)H(6). Even though highly unsaturated, they are not very reactive. Delocalized (pi) electrons confer special stability to aromatic compounds, aromatic hydrocarbons do not readily undergo addition reactions.
Possible relationships of 2 substituents on a benzene ring
ortho (substituents adjacent), meta (substituents 1 carbon apart), para (substituents opposite)
Alcohols
–C–O–H, prefix: -ol. Inserting an oxygen between C and H makes an alcohol. In the -OH (hydroxyl) group the oxygen is strongly and covalently bonded to both C and H. Longest carbon chain #ed from end closest to hydroxyl group, # designates the carbon to which hydroxyl is attached. Important in synthesis reactions.
Ethers
–C–O–C–, prefix: -oxy. Molecules with an oxygen atom between two carbons are ethers. When naming ethers, the longest carbon chain is listed second, and the shorter one listed first with the suffix -oxy.
Amines
R–N–R, prefix: amine. General formula of NR(3), where R is hydrogen or a hydrocarbon group.
Carbonyl-containing functional groups
Have C=O. The two other substituents on the sp^2 carbon determine the family of the compound
Aldehydes
O=C–H, prefix: -al. Must have at least one H atom attached to the carbonyl C, formula: R-CHO. # from aldehyde end (position does not need to be specified).
Ketones
O=C(–C)–C, prefix: one. Must have two carbons bonded to carbonyl carbon, formula: R-COR’. Chain #ed from end closest to carbonyl group.
Carbonxylic acids
O=C–OH, prefix: - oic acid. -OH group is attached to carbonyl group. #ed from acid end (position does not need to be specified), formula: R-COOH. Make up weak organic acids (lactic, acetic, citric acids and aspirin). Count carbon on carbonyl group with # of carbons.
Esters
O=C–O–C, prefix: -oate. Prepared via condensation rx w/ carboxylic acid and an alcohol. Named used alcohol 1st and then acid. -oate is attached to group w/o oxygen. Count carbon on carbonyl group with # of carbons.
Amides
O=C–N, prefix: -amide, N-. Composites of carbonyl and amine functionalities, formula: R-CONR’(2). Key functional group in the structure of proteins. Prefix N- is used to indicate which groups are bound to the nitrogen atom.
Condensation reactions
R-COOH + R’OH (R’NH(2)) –> R-COOR’ (RCONR’H) + H(2)O
Chirality
Isomers that are mirror images of each other and are non-superimposable. A carbon atom must have 4 DIFFERENT GROUPS attached to a chiral center. Double and triple bonds CANNOT be chiral.
Enantiomers
Two isomeric molecules that are mirror images of each other. Physical properties of enantiomers are identical. Type of stereoisomer. Also called optical isomers.
Optical isomers
Enantiomers are also called optical isomers. Number of optical isomers can be calculated by 2^n, where n = # of chiral centers.
Chiral centres
Carbon that has four different groups attached to it.
Naphthalene
C(10)H(8), aromatic hydrocarbon.
Anthracene
C(14)H(10), aromantic hydrocarbon.
Toluene
C(6)H(5)CH(3), aromantic hydrocarbon
Benzene
C(6)H(6), aromantic hydrocarbon.
Methane
CH(4)
Ethane
C(2)H(6)
Propane
C(3)H(8)
Butane
C(4)H(10)
Pentane
C(5)H(12)
Hexane
C(6)H(14)
Heptane
C(7)H(16)
Octane
C(8)H(18)
Nonane
C(9)H(20)
Decane
C(10)H(22)
Substituent prefix names
Di-, Tri-, Tetra-, Penta- (use when more than one of the same substituent)
F, Cl, Br, I names
Fluoro, Chloro, Bromo, Iodo (use when more than one of the same substituent)
