Fluorescenceand moleular characteristic Flashcards
the longer the wavelength….
the lower energy the radiation carries
what does high frequency mean for the wave length and energy?
shorter and higher
why is specroscopy important in pharmacy?
- used to determine the structure of an unknown molecule
- confirming the structure of a known molecule
- examples of spectroscopic application of drug discovery and pharmaceuticals
what kind of spectrscopy does IR measure higher or lower?
lower
what time of radiation can break bonds ?
UV-Vis spectrscopy
what is associated with Infrared absorption regarding the bonds?
vibrations
what does a vibration need to be, to be visible?
asymmetric there needs to be a dipole moment
what type of vibration should occur for the vibration to be visible?
-bending and asymmetrical stretching
what is the frequency for IR for N-H?
3300-3500cm-1
what is the frequency for IR for C-H alkyne?
3300cm-1
what is the frequency for IR for O-H?
3200-3400cm-1
what is the frequency for IR for C-H alkenyl?
> 3000cm-1
what is the frequency for IR for for C-H alkyl?
<3000cm-1
what is the frequency for IR for C-H?
2850-3100cm-1
what is the frequency for IR for C triple bond N or C triple bond C?
2100-2260cm-1
what is the frequency for IR for C=O?
1650-1800cm-1
what is the frequency for IR for the fingerprint region?
500-100cm-1
what affects the C=O frequency?
- electron withdrawing groups such as oxygen on neighbouring atom will increase number
- conjugation will reducde bond strength so number is lower
- electron donating groups like nitrogen will reduce
what is the typical UV-visible transition?
involves promotion of an electron from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital
the more conjugated the pie system…
the lower the energy require for an electronic transition
what is a chromophore?
functional group responsible for UV absroption
when may products become coloured ?
when the absorbed light is visile in the region and when they are highly conjugated natural products
what makes our blood red?
the haemoglobin because of the iron that has a very conjugated structure meaning it can absorb in the visible region
what is fluorescence?
when an atom that has been excited to a higher enegry level decays and goes back down to the loer level again
how does the energy decay?
decays via non radative ways like heat
