Chemical wedge

A molecule editor can draw a chemical structure and save it, for example as a Molfile. Although it is possible to include stereochemical properties in the drawing as wedges and hashed bonds, or even to assign a stereocenter/stereogroup with its identifiers R/S or E/Z), the connection table of the Molfile only represents the constitution (topology) of the molecule. 

To code the configuration of a molecule various methods are described in Section 2.8. In particular, the use of wedge symbols clearly demonstrates the value added if stereodescriptors are included in the chemical structure information. The inclusion of stereochemical information gives a more realistic view of the actual spatial arrangement of the atoms of the molecule imder consideration, and can therefore be regarded as between the 2D (topological) and the 3D representation of a chemical structure. 

The apparatus to use is seen in figure 13 which consists of a burette, thermometer, Erlenmeyer flask and a two-holed rubber stopper that has a small V-shaped wedge cut out of one side of the rubber stopper to allow the inside contents to vent. 31.5g of orangy-red fuming nitric acid (see chemicals section) is poured into the Erlenmeyer flask and the rubber stopper with its burette and thermometer is placed on to the... 

Figure 19 Crystal structure of the wedged manganese complex, 3,3, 4,4 -Mn(TMEDA)-commo-Mn[2,3-(SiMe3)2-2,3-C2B4HJ2. Reproduced by permission of the American Chemical Society from Organometallics 1996, 15, 626.

All chemical transformations relevant to metal/olefin reactions occur at the three orbitals in the plane between the two Cp rings or between the Cp and the N atom in the case of the CGC catalysts. This plane is usually referred to as the wedge or belt of the catalyst. The first detailed analysis of the electronic structure of group 4 metallocenes, and the implications on their chemistry, was performed by Lauher and Hoffmann with simple... 

In its disciplinary development at the end of the nineteenth century, physical chemistry served as a bridge, not a wedge, between the mathematical abstractions of theoretical physics and the metaphorical descriptions of organic chemistry. Not only through novel theories but also through control of new instrumentation, much of it electrical and optical in nature, physical chemistry was to revitalize and transform techniques in the chemical laboratory and theories of chemical explanation. Notably for our concerns, speculations about reaction mechanisms in hydrocarbon chemistry were to begin to proliferate in the early 1900s. 

Fig. 9.6 Human versus machine-readable chemical structure representations. Names based on the depicted structures were interpreted using ACDName [22]. The cross up/down wedge error (middle) causes errors in assigning the absolute chirality.

Wedge test results suggest that the curing process (e.g., percent crosslinking) of the epoxy-polyamide primer system is not affected by the addition of organosilanes, but may be affected by NTMP. The results of substrate surface characterization, adsorption behavior of applied films, and evaluation of candidate inhibitors by chemical, mechanical, and electrochemical test methods are presented. Mechanisms to explain the observed behavior of the various phosphonate and silane polymer systems are discussed. 

Write a simulation program to solve for the species-A mass-fraction field in the wedge section above the chemically active zone. Assume that the chemistry does not affect the velocity field as determined in the earlier sections. Plot and discuss the species profiles. 

Figure 10.20 A chemical double mutant cycle to assess the strength of edge-to-face n-n interactions (thick dashed wedges) in a molecular zipper complex AAG = AGA — ACB — AGc + A )>...

A conceptual DOM pie diagram (Fig. 1) represents the chemical view of the DOM pool of a typical riverine sample. The specific chemical classes or wedges can be separated based upon several different operational fractionation schemes (Thurman and Malcolm, 1981 Aiken, 1985 Aiken et al., 1992 Benner, 1998). For typical natural waters, the dominant fraction comprising DOM is fulvic acid, which is defined as the yellow, moderate molecular weight organic acid fraction of aquatic humic substances that is soluble at all pH values (Aiken et al., 1985). In surface waters receiving... 

Wedge, D. E., Camper, N. D. Connections between agrochemicals and pharmaceuticals. In Biologically Active Natural Products Agrochemicals and Pharmaceuticals. Cutler, H.G., Cutler, S. J. eds, ACS Symposium Series, American Chemical Society, Washington DC, 2000. ... 

When dendritic fragments are attached to polymer chains, the conformation of the polymer chain is strongly affected by the size and chemical structure of the dendritic wedges attached. Dense attachment of dendritic side chain converts a linear polymer into a cylindrically shaped, rigid and nanoscopic dimension. Frechet and Flawker [70] were one of the first to recognize these hybrid architectures . 

Figure 9.5. Specimen geometries prior to the final thinning step (a) dimpled specimen (b) wedge sample (c) lacquered window for chemical or electropolishing.

Nabholz JV, Clements RG, Zeeman MG, Osborn KC, Wedge R. 1993. Validation of structure activity relationships used by the USEPA s Office of Pollution Prevention and Toxics for the environmental hazard assessment of industrial chemicals. In Gorsuch JW, Dwyer FJ, Ingersoll CG, LaPoint TW, editors. Environmental toxicology and risk assessment. Volume 2. Philadelphia (PA) American Society for Testing and Materials, p 571-591. 

---