CHAPTER 1
INTRODUCTION
1.1. Crystal Engineering
The term crystal engineering was coined by Pepinsky in 1955 [1], and was first used in studies in 1971 by Schmidt seeking to define the term “crystal enginerring” in connection with topochemical reactions in crystalline cinnamic acids [2]. It has since expanded into the field of supramolecular chemistry, which deals with the interaction of molecules in a crystal through non-covalent bonds such as hydrogen bonding [3]. Crystal engineering has been defined as “the understanding of intermolecular interactions in the context of crystal packing and the utilization of such understanding in the design of new solids with desired physical and chemical properties” [4].
Crystal engineering is often based
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the assembled molecules, bound together with intramolecular interactions instead of covalent bonds. Supramolecular synthons have been defined by Desiraju [21] as “structural units within supermolecules which can be formed and/or assembled by known or conceivable synthetic operations involving intermolecular interactions”. The key in designing cocrystals is choosing a synthon, which is likely to form in a crystallization process, like a synthetic chemist chooses known reactants to make a specific covalent bond. Most often the synthons involve hydrogen bonds [22] because of their strength and directionality, but other interactions such as halogen bonding [23, 24] can also be used. Aromatic π- π interactions and van der Waals forces do not yet have much use in cocrystal design, but they are not to be overlooked in experiments because they contribute to the final outcome of …show more content…
It acts by inhibiting the body's production of prostaglandin. Ketoprofen is generally prescribed for arthritis-related inflammatory pains or severe toothaches that result in the inflammation of the gums. Ketoprofen topical plasters are being extensively used for treatment of musculoskeletal pain. The plasters have been shown to provide rapid and sustained delivery to underlying tissues without significantly increasing levels of drug concentration in the blood when compared to the traditional oral administration. Ketoprofen is used for its antipyretic, analgesic, and anti-inflammatory properties by inhibiting cyclooxygenase-1 and -2 (COX-1 and COX-2) enzymes reversibly, which decreases production of proinflammatory prostaglandin precursors
The goal of this experiment is to study the most precise way of measuring molecular bond lengths and introduction to computational software used for studying molecular properties. This is of interest in that the instrument to being used, a Fourier-transform infrared (FT-IR) spectrometer, can measure the vibrational and rotational transitions of the fundamental and first overtone of CO. Through this experiment the objective is to collect data from the aforementioned instrument in order to determine vibrational and rotational spectroscopic constants and CO’s bond length, then to compare them with quantum chemical calculation.
It has been argued that medication can contribute to pressure ulcers. Certain analgesics may reduce stimulus to relieve pressure ulcers. Non -steroidal anti-inflammatory drugs have been found to prevent inflammatory responses to pressure injuries thus worsening the condition. It has been found that nurses lack communication with a pharmacist regarding pressure ulcers in order to seek specialist advice (Royal college of nursing, 2001).
Svec and Frechet (1992) developed continuous methacrylate rods from glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA) as monomer and crosslinker. These two discoveries had a great impact, as they prov...
Tulunay, F. (2000). NSAIDs: behind the mechanisms of action. Functional Neurology, Suppl 15 (3) 202-207.
It is used for the treatment of arthritis and also for treating the back pain, shoulder pain and knee pain.
In order to separate the mixture of fluorene, o-toluic acid, and 1, 4-dibromobenzene, the previously learned techniques of extraction and crystallization are needed to perform the experiment. First, 10.0 mL of diethyl ether would be added to the mixture in a centrifuge tube (1) and shaken until the mixture completely dissolved (2). Diethyl ether is the best solvent for dissolving the mixture, because though it is a polar molecule, its ethyl groups make it a nonpolar solvent. The compounds, fluorene and 1, 4-dibromobenzene, are also nonpolar; therefore, it would be easier for it to be dissolved in this organic solvent.
Hospitals may use them for pain management for trauma-related injuries, cancer or post-surgery, and The Premier Safety Institute states that chronic pain is relieved using opioids on a short-term basis.
Thickett, Geoffrey. Chemistry 2: HSC course. N/A ed. Vol. 1. Milton: John Wiley & Sons Australia, 2006. 94-108. 1 vols. Print.
The covalent structure of a protein is composed of hundreds of individual bonds. Because free rotation is possible around a good portion of these bonds, there are a very high number of possible conformations the protein can assume. However, each protein is responsible for a particular chemical or structural function, signifying that each one has a distinctive three-dimensional configuration. By the early 1900’s, numerous proteins had been crystallized. Because the ordered collection of molecules in a crystal can only form if all of the molecular units are the same, the discovery that proteins could be crystallized proved that even large proteins have distinct chemical structures. This deduction completely transformed the understanding of proteins and their respective functions. It is important to investigate how a series of amino acids in a polypeptide chain is translated into a three-dimensional protein structure. There are five general topics related to this process: the structure of a protein is determined by its amino acid sequence, the role of a protein is dependent on its unique structure, an isolated protein typically exists in a small number of stable forms, non-covalent interactions are the most important stabilizing forces in a protein structure, and there are structural patterns that aid in explaining and understanding protein architecture.
23. S. Alwarappan, S. Boyapalle, A. Kumar, C.-Z. Li and S. Mohapatra, J. Phys. Chem. C, 2012, 116, 6556–6559
Steel: (for all intents and purposes) was invented in 1855 by Henry Bessemer(Mary Bellis). Science the amazing innovation that has changed the world incredible things have been made from the material from bridged cables and cross beams to arresting wires on aircraft carriers that stop monumental force and speed. It is truly an amazing martial, but eventually it snaps, breaks or tears due to the separation of the molecules. Also steel is not the most flexible material there is which may sound good for what it is used for, construction. You wouldn’t want the floor to shift from under but, what about in areas that have a consent threat of earthquakes having a material that is rigid when needed and flexible when needed would be an invaluable asset to construction companies in many countries. Also at $600-$900 per ton(Platts Mcgraw hill financial) it isn’t the most inexpensive material that could be chosen. Chemically is there a better material that could be used in the place of steel that is stronger more flexible and can be produced for a cheaper price than the normal steel that we use today? First, the choice of spider silk seems like a great choice. Mother nature seems to be the greatest designer of all made of different sections of proteins of extremely ridged and at the same time extremely elastic strings of proteins, that when braided together are 5 times stronger than steel and relatively free to produce as long as the spiders are kept healthy. What makes the proteins so strong? They are linked together almost like thousands of Lego’s linked together which by its self does not sound very strong, but just take 3 and pull length wise and try to pull them apart, it's almost impossible. The same concept is used in the spider's silk...
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.
Ionic compounds, when in the solid state, can be described as ionic lattices whose shapes are dictated by the need to place oppositely charged ions close to each other and similarly charged ions as far apart as possible. Though there is some structural diversity in ionic compounds, covalent compounds present us with a world of structural possibilities. From simple linear molecules like H2 to complex chains of atoms like butane (CH3CH2CH2CH3), covalent molecules can take on many shapes. To help decide which shape a polyatomic molecule might prefer we will use Valence Shell Electron Pair Repulsion theory (VSEPR). VSEPR states that electrons like to stay as far away from one another as possible to provide the lowest energy (i.e. most stable) structure for any bonding arrangement. In this way, VSEPR is a powerful tool for predicting the geometries of covalent molecules.
What exactly is a chemical engineer? Many would say that it is simply a "chemist who builds things" or an "engineer who makes chemicals. However, neither of these statements is completely true. The term "chemical engineer" is not meant to actually describe what it is a chemical engineer does, but to describe what sets it apart from the other branches of engineering: civil, mechanical, and electrical. On average, chemical engineers are numerically the smallest but also the highest paid. It is not a profession the must dwell on the past for comfort and support, for its greatest accomplishments are still yet to come.