Organic Chemistry I

Chapters 1, 2, 4, 5, 14, 15, 3

alkanes

single bonded hydrocarbons

methane

one carbon

ethane

two carbon

propane

three carbon

butane

four carbon

pentane

five carbon

hexane

six carbon

heptane

seven carbon

octane

eight carbon

nonane

nine carbon

decane

ten carbon

undecane

eleven carbon

dodecane

twelve carbon

tridecane

thirteen carbon

tetradecane

fourteen carbon

pentadecane

fifteen carbon

hexadecane

sixteen carbon

heptadecane

seventeen carbon

octadecane

eighteen carbon

nonadecane

nineteen carbon

icosane

twenty carbon

isomers

same formula, different arrangement of atoms

stereoisomers

spatial isomers; isomers that differ in their 3D orientation

enantiomers

type of stereoisomers; mirror images of a chiral molecule that are not superimposable

diastereomers

type of stereoisomers; not mirror images of one another

cis/trans isomers (geometric isomers)

type of diastereomers; restricted rotation about a molecule with double bonded carbons

conformational isomers

type of diastereomers; restricted roataion about a molecule with single bonded carbons

constitutional isomers (structural isomers)

type of isomer; different connectivity between atoms

axial bond

perpendicular to the plane of the molecule in 3D; vertical in chair conformation

equatorial bond

parallel to the plane of the molecule in 3D; horizontal in chair conformation

maximum number of stereoisomers

2^n (n=number of chiral centers in the molecule)

how to create another diastereomer?

change one of the wedged bonds to a dashed bond or one of the dashed bonds to a wedged bond

do diastereomers have different physical properties?

yes

formal charge

number valence electrons - number of bonds - number of free electrons

maximum number of bonds carbon can have

4

R configuration

clockwise

S configuration

counterclockwise

R-OH

alcohol

R-COOH

carboxyl

R-NHH

amino

R1-O-R2

ether

R-C=OH

aldehyde

R-X (X = Cl, Br, F)

haloalkane

C-C

alkane

C=C

alkene

R1-C(triple bond)C-R2

alkyne

R-SH

thiol

R-benzene ring

arene, aromatic

R1-C=O-R2

ketone

R-C(triple bond)N

nitrile

R1-C-O-R2

carbonyl

R1-C=O-O-R2

ester

R-C=O-X

acyl halide

C-C_O (in a triangular form)

epoxide

R-C=O-NHH

amide

Gauche conformation

two functional groups with a dihedral angle of 60 degrees increasing steric strain

steric strain

caused by large groups getting in each others way

torsional strain

increased repulsion between electron clouds due to the dihedral angle being minimized

eclipsed conformation

two functional groups with the smallest dihedral angle possible (highest in energy/least stable)

anti conformation

two functional groups that have a dihedral angle of 180 degrees

dihedral angle

angle between two adjacent atoms relative to the central C-C bond

Newman projection

perspective of looking straight down a particular C-C bond

staggered conformation

two functional groups that have the largest dihedral angle possible (lowest in energy/most stable)

bicyclic compound

two fused rings

sigma bond

single bond; head on head overlap of atoms along the internuclear axis

pi bond

double bond; lateral overlap of atoms with an electron density above and below the plane

molecular geometry of sp hybridization

linear (180)

molecular geometry of sp2 hybridization

trigonal planar (120)

molecular geometry of sp3 hybridization

tetrahedral (109.5)

molecular geometry of sp3d hybridization

trigonal bipyramidal (120 and 90)

molecular geometry of sp3d2 hybridization

octahedral (90)

cis conformation

same side of molecule

trans conformation

opposite side of molecule

if a molecule has a plane of symmetry, can it be chiral?

no

meso compounds

molecules with an even number of chiral centers with a plane of symmetry

if a compound has only one chiral center, will it be a chiral compound?

yes

Fischer projection

good for assessing stereoisomeric relationships; for large molecules with multiple chiral centers

allenes

compounds with two adjacent C=C bonds (R1-C=C=C-R2)

distillation

separates compounds with different boiling points

recrystallization

separates compounds with different solubilities

wavelength’s relationship to energy

inversely proportional

frequency’s relationship to energy

directly proportional

electromagnetic

the range of possible frequencies of light

what is NMR used for?

finding the specific arrangement off all carbons and hydrogens in the compound

what is IR spectroscopy used for?

finding the functional groups present in the compound

what is UV-VIS spectroscopy used for?

finding any conjugated pi system present in the compound

y-axis of IR absorption spectrum

% transmittance

x-axis of IR absorption spectrum

wavenumber (1/cm)

range of IR absorption spectrum

400-4000 (1/cm)

three characteristics of a signal on the IR spectrum

wavenumber, intensity, shape

stronger bond = ____ (higher/lower) stretching frequency

higher

larger mass difference = ____ (higher/lower) stretching frequency

higher

as the number of bonds carbon shares with other atoms (C, N, O) increases, the wavenumber _______ (increases/decreases)

increases

region above 1500 (1/cm)

diagnostic region

region below 1500 (1/cm)

fingerprint region

region where you will find bonds to hydrogen

2700-4000 (1/cm)

as the s character of carbon bonded to hydrogen increases (ex. sp3→sp2→sp), the ______ (stronger/weaker) the C-H bond, and so the _____ (higher/lower) the stretching frequency of the C-H bond.

stronger, higher

the more delocalized p electrons, the ______ (weaker/stronger) the p bond, and the _____ (lower/higher) the stretching frequency.

weaker, lower

the deeper the peak, the _____ (stronger/weaker) the signal.

stronger

greater bond polarity = ______ (stronger/weaker) IR signals

stronger