6th Flashcards
(29 cards)
🌷to predict how smt might react
or if they have reacted we should look at
movement of electrons
what is a resonance arrow used for
shows the interconversion between 2 different representations of the same molecule
if we draw an arrow from somewhere that place should then have
a positive charge
if we draw an arrow to somewhere that place should have a
negative charge
H+ number of electrons
0
this is a proton
electrons can be shared from a lone pair or a🌷
bond
arrow should be drawn through the C that is making the bond
the C would then have a +
species giving the electrons is called a🌷
nucleophile
attracted to positive
🌷species that receive the electrons
electrophile
attracted to the negative
the higher the enthalpy of hydrogenation🌷
the less stable it is
more energy released
energy released when smt is heated up
when double bonds and single bonds alternate
conjugated alkenes
what is a property of conjugated alkenes🌷
they are more stable than expected
they release less energy than expected
different between conjugated and non conjugated alkenes🌷
conjugated: pi orbitals overlap and interact + overlap allowing greater stability
non conjugated: pi orbitals are not close enough to interact + overlap and increase stability
how come they both have pi orbitals??
alkenes : sp2 hybridised meaning one 1 orbital is not hybridised and is free
orbitals
regions of space where electrons are likely to be found
nodes
areas of space where the probability of finding an electron is 0
points of 0 electron density
🌷the more conjugated a system is…
the less nodes there are
less nodes = lower energy
lower energy = more stable
particle in the box
3 nodes = highest energy empty
2 nodes = LUMO - lowest unoccupied molecular orbital) empty
1 node = HOMO - highest occupied molecular orbital) full
0 nodes = lowest energy full
in conjugated systems electrons can be🌷
shared throughout 1 extended molecular orbital
FORMS RESONANCE STRUCTURES
what do resonance structures help us understand🌷
how organic molecules may react
🌷resonance can also be called the
mesomeric effect
🌷what is the mesomeric effect
electrons being moved within a molecule
can influence: acidity, basicity + movement of charge
effects the behaviour of molecules
conjugated nucleophilic addition // michael addition
when u conjugate a molecule
u see it can react in a way u didn’t think it would before.
nucleophile attacking end carbon due to double bond electron density moving + leaving it with a + charge.
🌷conjugation can occur with bonds and
lone pairs!!!
whats so great about benzene + conjugation
resonance in benzene leads to greater stability than in linear conjugated alkenes.
this is bc p orbitals involved in pi bonds are aligned perfectly for max conjugation
