Porphyrins are a family of heterocyclic macrocycles molecules derived from the porphin. These molecules are composed of four modified pyrroles units linked through a methine bridges at their α carbon. Porphyrins are widespread throughout many living organisms. Compounds such as hemoglobin, cytochromes, chlorophylls are crucial for the survival of the vast majority of organisms. Since the first synthetic path for the formation of porphyrins was reported in the 1930s by Fisher1 and Rothemund2 simultaneously, extensive studies regarding coordination, polymerization and porphyrin modifications in the meso and β positions have been reported. These gives a lot of room to tailor the porphyrins so that they feature the desired properties. Porphyrins drawn the attention of scientist in many fields: artificial enzymes, catalytic reactions, organic photovoltaics and molecular electronics. …show more content…
The ability to modify the external parts of porphyrins extending their conjugated core or even coordinating metals or metalloids to induce a change in their conductivity and energy gap between HOMO and LUMO makes this type of molecules perfect candidates for molecular electronics. Moreover, their high molar absorption coefficients, their robustness, their tendency to act as donors and the aforementioned ability to tune their energy gap allow them to play an important role as electron donors in Organic Solar Cells. With these two branches of porphyrin applications continuously growing up, this project will be divided in two parts. The first part will correspond to the design and synthesis of a porphyrin for a specific purpose, in particular for Molecular Electronics, while the second part will relate to a more fundamental research where the change in optic and electrochemical properties of a porphyrin upon modification of its core by coordination will be
Compounds resulting from heterocyclic chemistry form a huge family of variations of organic compounds with cyclic or acyclic structures having carbons and at least another element with the most common being sulfur, oxygen, fluorine or nitrogen 49. Such heterocyclic compounds must have their rings having heteroatoms and the rings could be unsaturated or saturated as well 1. These compounds are usually classified as aromatic or alicyclic heterocycles 6. The latter contain cyclic analogues of thioethers, ethers and amines 6. It has been studied before that the families of nitrogen- sulfur heterocycles have aromatic compounds that are very stable19. Also, fluorinated compound using trifluoromethyl group is often used to reduce in vivo metabolism of potential drugs, in addition to improving cellular membrane permeability (LogP)88. Sulfur and Nitrogen organic compounds heterocycles are basically drawn from aromatic heterocycles realized when a heteroatom occupies the position of a carbon atom in the ring of an organic aromatic
In the ancient and medieval time, antipyretic agents were only found in willow bark and in cinchona bark [2]. Willow bark was used as a pain reliever [3]. People were advised to chew on the bark in order to relieve pain and fever [3]. Cinchona bark was used for increasing appetite, however people also used it for common cold and fever [4]. When the cinchona tree started to decrease in the 1880s, people started to look for other alternatives [2]. During the 1880s, antipyretics agents were developed, which were acetanilide and phenacetin [2]. These properties of acetaminophen were discovered by accident [2]. It occurred when the molecule acetanilide was added to a patient’s prescription [2]. By this time, this drug had been synthesized via the reduction of p-nitorphenol [2]. However the drug acetaminophen was still not used medically for another 20 years [2]. In 1893, acetaminophen was found in the urine sample of an individual who had taken phenacetin [2]. This drug was concentrated into an odorless, white, crystalline compound that was found to have a bitter taste [2]. Acetaminophen was discovered to be a metabolite of acetanilide, however the discovery was ignored at that time [2]. It was later on that acetaminophen was found to have pain and fever relieving properties
...hemical energy from cyanobacteria (the only bacteria that can perform photosynthesis) 2.4 billion years ago (Wernergreen). The first chloroplast came into being about one billion years ago when a single-celled protist and a cyanobacterium came together through endosymbiosis, and this first photosynthesizing eukaryotic lineage was the ancestor of land plants, green algae, and red algae. Cyanobacteria and algae endosymbionts have spread photosynthetic capabilities in such a broad range (Wernergreen). In other words, heterotrophic prokaryote cells had taken in autotrophic photosynthetic bacteria cells. The ingested cell continued to provide glucose and oxygen by photosynthesis. The host cell protected as well as provided carbon dioxide and nitrogen for the engulfed cell and overtime both cells lost the aptitude to survive without each other (Weber and Osteryoung).
The pi-bonding effect is another factor that contributes to trans effect. When pi-bonding ligand (T in figure 2) that is trans to X result in strong pi-b...
Some say they've seen vampires before, others say they're crazy but it just could possibly be the truth. Porphyria is the deficiency or inactivity of a specific enzyme in the heme production process. Porphyria effects different people in different ways. It is also the origin of the myth of vampires. Since there is no actual recording of vampires, this disease is the only thing that could make a person vampire-like. There are two main types of Porphyria; Acute Intermittent Porphyria and Cutaneous Porphyria. Both of which have negative effects that will affect a person badly. Porphyria effects the the body externally, internally, and family.
Thickett, Geoffrey. Chemistry 2: HSC course. N/A ed. Vol. 1. Milton: John Wiley & Sons Australia, 2006. 94-108. 1 vols. Print.
The Functions of Proteins Introduction Protein accounts for about three-fourths of the dry matter in humans. tissues other than fat and bone. It is a major structural component of hair, skin, nails, connective tissues, and body organs. It is required for practically every essential function in the body. Proteins are made from the following elements: carbon, hydrogen, oxygen, nitrogen. and often sulphur and phosphorus.
David and John Free. (26 Nov 2006). MadSci Network: Chemistry. Retrieved on March 6, 2011, from http://www.madsci.org/posts/archives/2007-02/1171045656.Ch.r.html
Background Information Aspirin is an analgesic (pain relieving) and an antipyretic drug (a drug that lowers body temperature). The main constituent of aspirin is 2 - ethanoythydroxybenzoic acid, also known as acetylsalicyclic acid (shown below right). It was originally made from just salicylic acid (which is found in the bark of a willow tree) when used by the Ancient Greeks to counter fever and pain, but its bitterness and tendency to irritate the stomach caused problems. These were resolved by the German chemist Felix Hoffman, who made the acetyl derivative of salicylic acid in the
23. S. Alwarappan, S. Boyapalle, A. Kumar, C.-Z. Li and S. Mohapatra, J. Phys. Chem. C, 2012, 116, 6556–6559
The structure of chlorophyll involves a hydrophobic tail embedded in the thylakoid membrane which repels water and a porphyrin ring which is a ring of four pyrrols (C4H5N) surrounding a metal ion which absorbs the incoming light energy, in the case of chlorophyll the metal ion is magnesium (Mg2+.) The electrons within the porphyrin ring are delocalised so the molecule has the potential to easily and quickly lose and gain electrons making the structure of chlorophyll ideal for photosynthesis. Chlorophyll is the most abundant photosynthetic pigment, absorbing red and blue wavelengths and reflecting green wavelengths, meaning plants containing chlorophyll appear green. There are many types of chlorophyll, including chlorophyll a, b, c1, c2, d and f. Chlorophyll a is present in all photosynthetic organisms and is the most common pigment with the molecular formula C55H72MgN4O5. Chlorophyll b is found in plants with the molecular formula C55H70MgN4O6, it is less abundant than chlorophyll a. Chlorophyll a and b are often found together as they increase the wavelengths of light absorbed. Chlorophyll c1 (C35H30O5N4Mg) and c2 (C35H28O5N4Mg) are found in algae, they are accessory pigments and have a brown colour. Chlorophyll c is able to absorb yellow and green light (500-600nm) that chlorophyll a
Although Solar Energy is a flexible source of where energy could be directly or indirectly converted into forms of energy, it’s still not perfect. With its inefficiency, scientists are trying to find alternative solution to store solar cells for as long as possible. The main process of capturing solar energy happens at the nanoscale. With solar cells, it gets more efficient the tinier it gets. The converting rate of solar energy is equally price competitive as fossil fuel, with a dollar per watt of solar energy. With the help of nanotechnology, it could help raise solar energy conversion efficiency and help lower costs making it the ultimate method of raw energy conversion. To make sure the process of generating energy is kept at a low cost and energy output...
Plontke, R. (2003, March 13). Chemnitz UT. TU Chemnitz: - Technische Universität Chemnitz. Retrieved April 1, 2014, from http://www.tu-chemnitz.de/en/
V. Amarnath, D. C. Anthony, K. Amarnath, W. M. Valentine, L. A. Wetterau, D. G. J. Org. Chem. 1991, 56, p. 6924-6931.
As they always say HEALTH IS WEALTH! Your food selection today, makes you enjoy for the moment and affects your health tomorrow and in the future!