Electronic spectroscopy Flashcards
Where do electronic transitions occur?
Atomic orbitals in atoms
Molecular orbitals in molecules
Where do electronic transitions occur in alkanes?
Sigma to sigma star
Where do electronic transitions occur in carbonyl compounds?
Sigma to pi star
n to pi star
Where do electronic transitions occur in alkenes, alkynes and carbonyl compounds?
pi to pi star
Where do electron transitions occur in nitrogen, sulfur, oxygen and halogen compounds?
n to sigma star
What is n?
Non-bonding orbital
Which orbitals are filled?
Sigma
Pi
n
Which orbitals are empty?
Pi star
Sigma star
What happens to the wavelength if the amount of conjugation increases?
Becomes longer
What is a chromophore?
A region in a molecule where the energy difference between two different molecular orbitals falls within the range of the visible spectrum
What happens to visible light that hits the chromophore?
Absorbed by exciting an electron from its ground state into an excited state
What are the two forms chromophores arise in?
Conjugated pi systems
Metal complexes
What causes the conformational change of he molecule when hit by light?
Chromophore
What is pi conjugation?
Alternating single and double bonds which allow for electrons to be transferred from a filled orbital to an empty orbital
What do selection rules tell us?
If a reaction is likely and favourable
