What is Fieser Kuhn rule?
What is Fieser Kuhn rule?
Fieser-Kuhn Rule for Conjugated Polyenes n is the number of conjugated double bonds. Thus using the above equations, one can get the wavelength of maximum absorbance (λmax) and the maximum absorptivity (εmax)
What is Homoannular and Heteroannular diene?
a) Homoannular Diene:- Cyclic diene having conjugated double bonds in same ring. b) Heteroannular Diene:- Cyclic diene having conjugated double bonds in different rings.
What is the UV range of Homoannular conjugated diene system?
The base value for homoannular diene system is 253 nm according to the Woodward-Fieser rules.
What is λ max?
Lambda max (λmax): The wavelength at which a substance has its strongest photon absorption (highest point along the spectrum’s y-axis).
What wavelength absorbs lycopene?
Lycopene has three peaks of absorbance, 444, 471 and 503 nm. This third peak is at a wavelength at which the absorbance of β-carotene (and other minor carotenoids) have relatively low absorbance and thus cause very little interference.
What is Woodward-Fieser rule for diene?
One set of Woodward–Fieser rules for dienes is outlined in table 1. A diene is either homoannular with both double bonds contained in one ring or heteroannular with two double bonds distributed between two rings. In the compound on the left, the base value is 214 nm (a heteroannular diene).
What is Woodward-Fieser law?
After studying a large number of diferent conjugated dienes, Woodward and Fieser came up with an empirical correlation between the structural changes and λmax, that enable us to predict the λmax of an unknown diene. These are called Woodward-Fieser rules.
How are Woodward Fieser rules calculated?
Woodward-Fieser Rules for Calculating the π → π* λmax of Conjugated Carbonyl Compounds. (i) Each exocyclic double bond adds 5 nm. In the example on the right, there are two exo-double bond components: one to ring A and the other to ring B.
What is lambda max in UV VIS?
Lambda max (λmax): The wavelength at which a substance has its strongest photon absorption (highest point along the spectrum’s y-axis). This ultraviolet-visible spectrum for lycopene has λmax = 471 nm.
What is maximum absorbance?
Looking at the absorbance spectrum, the maximum absorbance peak is between 850 and 900 nm. More specifically, a wavelength around 880 nm seems the most appropriate choice.
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