Organic Chemistry from Uni Flashcards
e fuck you whats a constitutional isomer, actual spastic honestly
compounds with same chemical formula but different order of attachment
in organic compounds what does prefix show
number of carbons in parent chain
in organic compounds what does infix show
nature of the bonding in the parent chain
in organic compounds what does suffix show
the functional group(s) present in the compound
infix -an-
all single bonds
infix -en-
one or more double bonds
infix -yn-
one or more triple bonds
constitutional isomerism
different compounds that have the same molecular formula
conformation
any 3 dimensional arragnement of atoms in a molecule that results in rotation about a single bond
eclipsed and staggered
eclipsed has steric repulsion
steric repulsion
what is a functional group
Additional atom or groups of atoms (containing elements in addition to H and C) found on a mostly hydrocarbon molecule
alcohol functional group
All alcohols contain the –OH group, these are attached to a carbon atom
Called Hydroxyl functional group
how are alcohols classifyed
Classified as primary (1°), secondary (2°) or tertiary (3°) depending on
how many C’s are attached to the carbon bearing the OH group (CH3OH is a
special case)
other functional groups containing double bonds
hydroxyl = alcohols
carbonyl = aldehydes and ketones
carboxyl = carboxylic acids
The Carbonyl Group
Aldehydes and ketones both contain the same functional group, the carbonyl
group (C=O), but they differ in the way that the carbonyl group is bonded to the rest of the molecule.
The functional group found in all Carboxylic Acids is the carboxyl group (—COOH). Acetic acid
no total valence electrons
NF3 = [1 x N (5e-)] + [3 x F (7e-)] = 5 + 21 = 26 valence
electrons
special properties of carbon
- forms strong bonds with many other elements and with itself. 2. has a variety of bonding modes - allows great structural variation.
- can combine to form chains and rings of carbon and other atoms.
alkane definiton
Alkane definition: A saturated hydrocarbon whose carbon atoms are arranged in an open chain (SH) only C-C single bonds. Nomenclature (ane: ending)
Constitutional Isomerism
Different compounds that have the same molecular formula For the hydrocarbons CH4 or C2H6 only one isomer is possible however,
Structural isomers = Constitutional Isomer
staggerred confimration
The staggered conformation is the most stable conformation because the
less –ve and –ve bond repulsion
Cyclolhexane is not a completely inflexible it can be twisted into two main
conformations: boat and chair.
The chair conformation is the most stable, why?
Both have 109.5
Deg C-bond angles
In the chair conformation, exists two types of positions the hydrogen atom can be in, one where the hydrogen is axial (perpendicular to the ring) and one where the hydrogen is equatorial (in the plane of the ring)
saturated hydrocarbons
alkanes
unsaturated hydrocarbons
alkenes, alkynes, arenes
alkanes carbon-carbon bonding
only carbon-carbon single bonds
alkenes carbon-carbon bonding
one or more carbon-carbon double bonds
alkynes carbon-carbon bonding
one or more carbon-carbon triple bonds
arenes carbon-carbon bonding
one or more benzene-like rings
NO, the carbon-carbon double bond restricts rotation (because of the additional
p-Bonding) and alkenes in this position are in a fixed conformation
stereoisomers (theyre spacial isomers (3D orientation))
Compounds with two different groups on each carbon attached to the double bond
have cis
-trans isomers. These isomers are grouped into a class of compounds
called stereoisomers: same atom connectivity but a different orientation in space
Cis-Trans isomers require each carbon is bonded to two different groups, and that
the two carbons in the double bond have at least one substituent in common
The cis
& trans designation does not work when all substituents
on the double bond are different
The substituents are assigned a priority based on atomic weight:
Zusammen means what
means together
Entgegen means what
means opposite
what is E and Z-configurations priority based on
E and Z-configurations priority is based on atomic number
* Or at the first point of difference:
Addition of the reagent across the alkene double bond
Addition of the reagent across the alkene double bond, HCl
hydrochloronation
Addition of the reagent across the alkene double bond, H20
hydration
Addition of the reagent across the alkene double bond, Br2
bromination
Addition of the reagent across the alkene double bond, H2
hydrogenation
Electrophiles
(electron deficient)- contain an atom with a positive or partial
positive charge:
H-Cl, H-Br, H-I, H
2O all contain hydrogens with partial positive charges
Nucleophiles
(electron rich)- contain an atom with a negative charge or lone
pair of electrons:
The double bond in an alkene is a nucleophile.
regioselective definition
The reaction is regioselective: “A reaction in which one direction of bond forming or bond breaking occurs in preference to all others”
The regioselectivity can be explained with respect to Carbocation stability
Hydrogenation
catalytic reduction of alkenes
Syn-addition
(hydrogens add to same side) – cis product results
Catalysts adsorbs hydrogen and alkene onto the surface and is an
Exothermic process.
Resonance energy:
The difference in energy between a resonance hybrid and most stable
hypothetical contributing structure
Dramatic effect on reactivity.
alkynes
Contain a C≡C triple bond, also called acetylenes
Amines
Amines are derivatives of ammonia, - one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group (R)
Replace the suffix -e of the parent alkane with –amine.
what does Primary, secondary, tertiary (1o, 2o, 3o) refer to in animes
Primary, secondary, tertiary (1o, 2o, 3o) refer to the degree of substitution on
the nitrogen.
The larger the hydrocarbon component becomes the less soluble in water
the amine is. The opposite can be said for amines solubility in organic solvents
isomers
different compounds with
the same molecular formula:
bonds would have to be broken
and reformed to convert from
one to another
sterioisomers
isomers with the same order
of attachment of atoms, but a
different orientation of their
atoms in space
constitutional isomers
isomers with a different
order of attachment
of their atoms
Diastereomers
stereoisomers that
are not mirror images
Enantiomers
stereoisomers that are
nonsuperimposable
mirror images of each other
chiral definition
Molecule or object that is not superimposable on its mirror image is chiral
Chiral: any object that is not superposable on its mirror image
Example: your hands
Enantiomers
stereoisomers that are nonsuperposable mirror images
Enantiomers have the same boiling point, melting point and solubility.
Each enantiomer reacts differently towards other chiral molecules.
requirement for a molecules to be chiral
For a molecule to be chiral first it must have a Stereogenic center
what is a steriogenic centre
Stereogenic center: a carbon atom bearing four different substituents.
definition
Achiral: any object that is superimposable on their mirror image
Example: your socks
Diastereoisomers
2n where n is the number of stereogenic centres
