On this day, 65 years ago, November 29, 1960 (October 11, 1960 in the lunar calendar), chlorophyll synthesis was successful. On November 29, 1960, German scientist Martin Strell and American scientist Robert Burns Woodward successfully synthesized chlorophyll. Chlorophyll is one of the most effective substances that can convert light into energy. One of the most important pigments involved in photosynthesis. Photosynthesis is the process of converting light energy into chemical energy by synthesizing some organic compounds. Chlorophyll is found in virtually all organisms capable of photosynthesis, including green plants, prokaryotic blue-green algae (cyanobacteria) and eukaryotic algae. Chlorophyll absorbs energy from light, and the energy is then used to convert carbon dioxide into carbohydrates. There are several different types of chlorophyll: chlorophyll a and b are the main types and are found in higher plants and green algae; chlorophyll c and d are found in various algae and often coexist with chlorophyll a; chlorophyll e is rare and is found in some golden algae; Bacterial chlorophyll is found in some bacteria. In green plants, chlorophyll is found in membrane-like disk-shaped units (thylakoids) within organelles called chloroplasts. The chlorophyll molecule contains a central magnesium atom and a nitrogen-containing structure on the periphery, called a porphyrin ring; a long carbon-hydrogen side chain (called chlorophyllol chain) is connected to the porphyrin ring. Differences in chlorophyll types are caused by minor changes in certain side groups. Chlorophyll is very similar in structure to heme, a pigment found in red blood cells in mammals and other vertebrates and used to carry oxygen. Molecular three-dimensional model Green plants use carbon dioxide in the air, sunlight, water and minerals in the soil to make food for themselves. The whole process is called "photosynthesis", and the required sunlight is absorbed by the green elements in the leaves. This green organic compound is chlorophyll. Chlorophyll: The green pigment in the photosynthesis membrane, which is the main component that captures light during photosynthesis. Chlorophyll (chll) in chloroplasts of higher plants mainly includes two types: chlorophyll a and chlorophyll b. The molecular formula is C40H70O5N4Mg, which is a synthetic natural low-molecular organic compound. Chlorophyll is not an aromatic compound. They are not soluble in water, but soluble in organic solvents such as ethanol, acetone, ether, chloroform, etc. In terms of color, chlorophyll a is blue-green, while chlorophyll b is yellow-green. In the structure diagram of chlorophyll shown on the right, it can be seen that this molecule contains three types of double bonds, namely, carbon-carbon double bonds, carbon-oxygen double bonds and carbon-nitrogen double bonds. Chemically speaking, chlorophyll is an ester of chlorophyllin and can undergo a saponification reaction. Chlorophyllin is a dicarboxylic acid in which one carboxyl group is esterified with methanol and the other is esterified with leaf alcohol. The chlorophyll molecule contains a "head" of a porphyrin ring and a "tail" of chlorophyllol. The magnesium atom sits in the center of the porphyrin ring and tends to be positively charged, while the nitrogen atom associated with it tends to be negatively charged. Therefore, the porphyrin is polar, hydrophilic, and can bind to proteins. Leaf alcohol is a diterpene composed of four isoprene units, a lipophilic fatty chain that determines the lipid solubility of chlorophyll. Chlorophyll does not participate in the transfer of hydrogen or the oxidation and reduction of hydrogen, but only participates in the transfer of energy in the form of electron transfer (i.e., oxidation and reduction caused by electron gain and loss) and conjugate transfer (direct energy transfer). The magnesium atom in the porphyrin ring can be replaced by H, Cu2, and Zn2. When treating leaves with acid, H easily enters the chloroplasts and replaces magnesium atoms to form de-magnesium chlorophyll, making the leaves brown. Demagnesium chlorophyll can easily combine with copper ions to form copper-substituted chlorophyll, and its color is more stable than before. People often use copper acetate to preserve green plant specimens based on this principle. There are 4 species a, b, c and d. All plants that release oxygen during photosynthesis contain chlorophyll a; chlorophyll b is found in higher plants, green algae and euglena; chlorophyll c is found in diatoms, flagellates and brown algae, and chlorophyll d is found in red algae. The molecular structure of chlorophyll a consists of four pyrrole rings connected through four methenyl groups (=CH-) to form a cyclic structure, called porphyrins (with side chains on the rings). A magnesium atom is bonded to the center of the porphyrin ring and a cyclopentanone (V). The propionic acid on ring IV is esterified and saponified by chlorophyllol (C20H39OH) to form a water-soluble potassium salt. In an acidic environment, magnesium in the porphyrin ring can be replaced by H, which is called demagnesium-chlorophyll and is brown. When H is replaced by copper or zinc, its color turns green again. This pigment is stable and does not fade under light. It is not destroyed by acid. This property is used to preserve soaked plant specimens. In photosynthesis, the vast majority of chlorophyll functions to absorb and transfer light energy, and only a very small number of chlorophyll a molecules function to convert light energy. They are probably bound to proteins in vivo and present on the thylakoid membrane. Phylochol is a lipophilic aliphatic chain. Its existence determines the lipid solubility of chlorophyll molecules and makes it soluble in organic solvents such as acetone, alcohol, and ether. It mainly absorbs red light and blue-violet light (the red part of 640-660nm and the strong absorption peak of blue-violet light from 430-450nm), because chlorophyll basically does not absorb green light, allowing green light to pass through and appear green. Due to differences in structure, chlorophyll a is blue-green, and b is yellow-green. It is easily oxidized and discolored under light. Chlorophyll is an ester of a dicarboxylic acid that undergoes a saponification reaction with alkali. Comment: The most important pigment in photosynthesis