Spectroscopy: UV spectra MiniQuiz Conclusion Unknown 2/ Introduction Unknown 3: Nitro compounds. Inert Compounds. Today:
Dec 21, 2015
Spectroscopy:
UV spectra
MiniQuiz
Conclusion Unknown 2/ Introduction Unknown 3:
Nitro compounds. Inert Compounds.
Today:
Nitro Compounds Typical properties?
Classification test:
Always do with a known compound to compare!
Derivatives (if no other functional group available):
Reduce to amine and then prepare amine derivatives
• Preliminary tests?
• Solubility
• Classification tests
• Derivatives
• Spectra
Iron (II) Hydroxide Test for Nitro GroupsNitro Compounds
Carboxylic Acids
IR:
H-NMR:
• Preliminary tests?
• Solubility
• Classification tests
• Derivatives
• Spectra
OH in gas phase(non-H-bonded)
AminesIR
H-NMR
Voodoo Lily
Amorphophallus
Amides
H-NMR:
• Preliminary tests?
• Solubility
• Classification tests
• Derivatives
• SpectraIR?
Unknown 3can be “anything”:
Any of the functional groups of unknowns 1 and 2;also
“Inert compounds”
“Inert Compounds”
Alkanes
Aromatic Hydrocarbons
Alkyl halides. Aryl halides.
Chemical tests and derivatives depend on compound.
• Beilstein test (p.626) for Cl, Br Compare with known compound!
See Chapter in your Lecture text (conjugated systems)
to* HOMO to LUMO
A = x C x l
A = absorbance; = molar absorptivity
C = concentration in mol/L; l = sample pathlength in cm
UV/Visible Spectrophotometry
• Range of UV in nm?
• Which compounds generally absorb in the UV? CH4? CH3(CH2)10CH3? Ethanol? Benzene?
Naphtalene? -Carotene? FeCl3?
• Which compounds absorb in the visible range?CH4? CH3(CH2)10CH3? Ethanol? Benzene?
Naphtalene? -Carotene? FeCl3?
UV/Visible Spectrophotometry
max
Next time:
• Infrared spectrophotometry (IR)
• MiniQuiz on today’s class