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Leaves change color in the fall because their chromophores (chlorophyll molecules) break down and stop absorbing red and blue light. [1] A chromophore is a molecule which absorbs light at a particular wavelength and reflects color as a result. Chromophores are commonly referred to as colored molecules for this reason.
Benzene is a natural constituent of petroleum and is one of the elementary petrochemicals. Due to the cyclic continuous pi bonds between the carbon atoms, benzene is classed as an aromatic hydrocarbon. Benzene is a colorless and highly flammable liquid with a sweet smell, and is partially responsible for the aroma of gasoline.
For example, benzene does not display colour as it does not have a chromophore; but nitrobenzene is pale yellow colour because of the presence of a nitro group (−NO 2) which acts as a chromophore. But p-hydroxynitrobenzene exhibits a deep yellow colour, in which the −OH group acts as an auxochrome.
The quinones are a class of organic compounds that are formally "derived from aromatic compounds [such as benzene or naphthalene] by conversion of an even number of –CH= groups into –C(=O)– groups with any necessary rearrangement of double bonds", resulting in "a fully conjugated cyclic dione structure".
By integrating a benzene ring into the polyene part, these compounds have a styrene partial structure. Styryl dyes are used as disperse dyes in the dyeing of polyester fibers. Example: Preparation of C.I. Disperse Yellow 31 (3) by condensation of ethyl cyanoacetate (1) with a p-aminobenzaldehyde derivative. [3]: S. 58
The chromophore is derived from Glu-63, Tyr-64 and Gly-65 and the phenolic group of Tyr-64 plays a vital role in the formation of a conjugated system with the imidazolidone moiety resulting a high absorbance in the absorption spectrum of chromoprotein in the excited state. The replacement of Tyrosine with other amino acids leads to the ...
The phenyl group is closely related to benzene and can be viewed as a benzene ring, minus a hydrogen, which may be replaced by some other element or compound to serve as a functional group. A phenyl group has six carbon atoms bonded together in a hexagonal planar ring, five of which are bonded to individual hydrogen atoms, with the remaining ...
Pentacene (C 22 H 14) is a polycyclic aromatic hydrocarbon consisting of five linearly-fused benzene (C 6 H 6) rings.This highly conjugated compound is an organic semiconductor.The compound generates excitons upon absorption of ultra-violet or visible light; this makes it very sensitive to oxidation.