Question

Questions in photo. From the Green Synthesis and Study of a Fluorescent Natural Product experiment.

Fluorescence Data: Describe the observed under the UV light in the test tube and on the filter paper. (e.g. color, brightness etc. fluorescent activity of each test tube of the 4-methylumbelliferone i ) Draw the structure of 4- erone under the neutral, acidic and basic conditions. For the acidic and basic conditions drawa methylumbellif resonance structure to depict a new chromophore likely responsible for its abs consider 1,4-benzoquinone-like structures as seen with phenolphthalein under bas racteristics. (Hint: orbance cha Fluorescence Characteristics (intensity, color, etc. Conditions Quinone-like Resonance Structure (Chromophore) Major Structure Neutral Not needed here Acidic Basic Process of Fluorescence: Describe what is responsible for the light emission that is observed. In other words, why do certain compounds fluoresce?

Answer 1

Neutral: white HO 4-Methylumbelliferone Acidic: Red/pink HO Basic: Yellow Fluorescence occurs when a substance releases absorbed energy in the form of light. A fluorescent substance absorbs electromagnetic radiation (often UV-light which promotes the electrons to a higher energy level. While in the higher energy state, the electron loses some energy in the form of heat. Then the electron relaxes back to its ground state energy and then emits a photon in the process. This light is the characteristic fluorescent color.