Functional Groups Flashcards
Carbon-oxygen bonding
form covalent bonds via hybrid orbitals
requires 2 extra 2e- to fulfil the octet rule
can bond to carbon via a single bond- form a tetrahedral arrangement around oxygen
can form double bonds
in sigma portion have a pair of e- that also form trigonal arrangement
leave unhybridised p orbital to form pi bond
alcohols
hydroxyl group -OH
primary, secondary or tertiary
aldehydes
terminal carbon group -CHO
C always =O
always at end of molecule
carbonyl group has the lowest possible number
ketones
carbonyl group >C=O
never at the end of the chain
functional group is always in the middle
carboxylic acids
terminal carbonyl and hydroxyl group -COOH
alway at end of the chain
ethers
O atom connected to 2 alkyl or aromatic groups
name both sides of chain next to O atom
esters
derived from carboxylic acid
name on both sides of the functional group
O in middle of the chain attached to =O
Functional group + OH group
use prefix -hydroxy
carbon-nitrogen bonding
bind via hybrid orbitals
form covalent bonds to C atoms through hybrid orbitals
requires 3e- to fulfil octet rule
amines
contain single bonded nitrogen
primary- N can be at the end of the molecule
secondary- N in the middle of the chain
tertiary- N bound to 3 different C atoms
imines
possesses a C=N double bond
nitriles
possesses a C-N triple bond
triple bonds can be toxic
amides
comprise of a carbonyl group -C=O attached to an amine group
can be primary, secondary or tertiary
amino acids
contain a primary amine (-NH2) and carbonyl (-COOH) group
important as its a peptide bond
shape of organic molecules
e- in different orbitals repel each other
mutual repulsion will much the molecular orbitals as far apart as possible
tetrahedral arrangement of 4 bonded e- pairs
reactivity often dependent on molecular shape
sp3 hybridised atoms
single bonds
tetrahedral geometry of e- pairs
sp2 hybridised atoms
contains double binds
trigonal planar geometry of e- pairs
trigonal arrangement to minimise e- repulsions
sp hybridised atoms
contains triple bonds
linear arrangement of e- pairs
what are the 3 types of isomerism?
structural
geometric stereoisomerism
optical isomerism
structural isomers
alcohols:
boiling points different in alcohols
alcohols can be oxidised
reactivities different as well as boiling points
ethers:
react differently to alcohols
optical isomers
amino acids exhibit optical isomerism
central C is a chiral centre- bound to NH2, COOH and H
exist as enantiomers
rotate the plane of polarised light by equal amounts in opposite directions
biological systems and enantiomers
very selective
enzyme reactions are often enantioselective
chemical cannot tell which is present, cannot separate them, biologically act different
chiral centres
cannot be a double bond
end carbon cannot be chiral
link between electronic configuration, orbital hybridisation & molecular shape
C, O and N form bonds through hybrid orbitals
sp3, sp2 or sp
single, double or triple bonded
tetrahedral, trigonal or linear
