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Chemical Reaction Optimization
Published in Nazmul Siddique, Hojjat Adeli, Nature-Inspired Computing, 2017
Chemistry is a branch of natural science that studies the properties, composition, and structure of matter and how it reacts and changes under certain conditions when it comes in contact with other kinds of matter. Early chemistry was dominated by alchemy and phlogiston theories, which dominated the subject for centuries. It was Antoine Laurent Lavoisier (1743–1794) who disproved the phlogiston theory and thus emancipated chemistry from alchemy in the eighteenth century. He introduced modern chemistry by discovering the law of conservation of mass. The law of conservation of mass states that mass can neither be created nor be destroyed. It changes from one form to another. John Dalton (1766–1844) proclaimed the existence of elementary atoms and postulated that groups of atoms disassociate and then rejoin in new arrangements during chemical reactions. Atomic structure constrains different atoms to form groups in fixed ways as molecules. A molecule comprising several atoms is characterized by the atom type, bond between atoms, angle, and torsion (twisting of structure), which is termed molecular structure. Chemical reactions are explained in terms of atomic structure of matter and of energy changes that occur during reaction. In a chemical reaction, chemical bonds are broken into molecules by absorption of energy and new bonds are formed producing different molecules with release of energy. A chemical reaction comprises different types of unimolecular and multimolecular elementary reactions, each of which releases or absorbs different levels of energy. Tobern Olof Bergman (1735–1784) used diagrams and symbols to explain chemical reactions. Thus, chemistry took its present scientific form in which chemical reactions are represented by chemical equations. The law of conservation holds during any chemical reaction. Thus, the same collection of atoms is present after a reaction as before the reaction. The changes that occur during a reaction involve just the rearrangement of atoms.
Syntheses, characterization, and crystal structures of ruthenium(II)/(III) complexes with tridentate salicylaldiminato ligands
Published in Journal of Coordination Chemistry, 2018
Fule Wu, Chang-Jiu Wang, Hui Lin, Ai-Quan Jia, Qian-Feng Zhang
In summary, the reaction behavior of the versatile tridentate Schiff base 2-[(2-dimethylamino-ethylimino)-methyl]-phenol (HL) towards several common ruthenium(II)/ruthenium(III) starting materials was investigated. Decomposition of the HL and oxidation of ruthenium center occurred during the reaction employing [Ru(PPh3)3Cl2]. Oxidation of the metal center was also observed when [Ru(tht)4Cl2] was used [36, 37]. Three new ruthenium(II)/(III) complexes with tridentate Schiff base L have been synthesized and characterized by microanalytical and spectroscopic methods. Their molecular structures have been further determined by X-ray crystallography. The bite O-Ru-N angles of 91.46(6)°, 171.47(6)° and 175.47(8)° for 2·CH2Cl2, 3 and 4, respectively, shows the flexibility of the tridentate Schiff base ligands.
Density functional theory study of a silver N-heterocyclic carbene complex
Published in Journal of the Chinese Advanced Materials Society, 2018
Senem Akkoç, Sevtap Çağlar Yavuz, Mehmet Akkurt, Cem Cüneyt Ersanlı
First, the geometry of molecule 2 was created using the Spartan 10 package software [33]. This geometry was optimized using the B3LYP/6-31G* basis set in the Spartan 10 package software. The optimized energies of the molecule were found at the end of the optimization. The molecular bond angles, torsion angles and bond lengths were determined at the end of this optimization. Since the studied molecular structure was determined by the X-ray diffraction method, the obtained experimental values were compared with the calculated geometric parameters.