Colours and Chromophores Flashcards
What colours are absorbed when you see white?
none, everything is reflected
What colours are absorbed when you see black?
all of them
What colours are absorbed when something looks clear?
none, everything is transmitted
What does increasing conjugation do to the gap between the homo and lumo?
it decreases it
Does vibrational cooling release light? What is another name for this process?
does not release light
also called vibrational decay
What can happen to an electron once it is at the S1, V0 state?
fluorescence internal conversion (non-radiative) intersystem crossing to the triplet state and phosphorescence energy transfer to another molecule chemical reactions
What happens to energy during internal conversion? How fast is this?
it is lost as heat
depends on the molecule, can be very slow or very fast
What causes phosphorescence?
intersystem crossing and transition from T1 to S0
Which is slower fluorescence or phosphorescence?
phosphorescence is usually slower i.e. glow in the dark toys
What two things can happen during a T1 to S0 transition?
phosphorescence or internal conversion (lost as heat)
What is an auxochrome?
A group or substructure that influences the absorption of a chromophore
Name 8 key differences between heme and chlorophyll
chlorophyll has Mg2+, heme has Fe2+
chlorophyll’s coordination number is 4, heme’s is 6
chlorophyll has one C=C bond that is reduced to C-C
chlorophyll has an extra ring
chlorophyll has two forms, a and b
chlorophyll appears green
chlorophyll has a hydrophobic terpene tail made of isoprene (5C) units
Which form of chlorophyll has an aldehyde? Which has a methyl?
a has a methyl
b has an aldehyde
What does the hydrophobic tail of chlorophyll do?
it can bind to the membrane and leave the active part out
