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A number of illustrative examples of SMARTS have been assembled by Daylight. The definitions of hydrogen bond donors and acceptors used to apply Lipinski's Rule of Five [6] are easily coded in SMARTS. Donors are defined as nitrogen or oxygen atoms that have at least one directly bonded hydrogen atom:
For example, the compound water (H 2 O), has a molecular weight of 18 since hydrogen has a mass of 1.01 and oxygen 16.00, and its mass spectrum has a peak at 18 units. Heuristic Dendral would use this input mass and the knowledge of atomic mass numbers and valence rules, to determine the possible combinations of atomic constituents whose mass ...
For example, F/C=C/F (see depiction) is one representation of trans-1,2-difluoroethylene, in which the fluorine atoms are on opposite sides of the double bond (as shown in the figure), whereas F/C=C\F (see depiction) is one possible representation of cis-1,2-difluoroethylene, in which the fluorines are on the same side of the double bond.
A space-filling model of n-octane, the straight chain (normal) hydrocarbon composed of 8 carbons and 18 hydrogens, formulae: CH 3 CH 2 (CH 2) 4 CH 2 CH 3 or C 8 H 18.Note, the representative shown is of a single conformational "pose" of a population of molecules, which, because of low Gibbs energy barriers to rotation about its carbon-carbon bonds (giving the carbon "chain" great flexibility ...
DNA-encoded chemical libraries (DECL) is a technology for the synthesis and screening on an unprecedented scale of collections of small molecule compounds. DECL is used in medicinal chemistry to bridge the fields of combinatorial chemistry and molecular biology.
Note how the size of the carbon appears smaller than the hydrogen. The importance of stereochemistry was not then recognised and the model is essentially topological (it should be a 3-dimensional tetrahedron). Jacobus Henricus van 't Hoff and Joseph Le Bel introduced the concept of chemistry in three dimensions of space, that is, stereochemistry.
This is a list of important publications in chemistry, organized by field. [1] [2] [3] [4]Some factors that correlate with publication notability include: Topic creator – A publication that created a new topic.
Chemometrics is the science of extracting information from chemical systems by data-driven means. Chemometrics is inherently interdisciplinary, using methods frequently employed in core data-analytic disciplines such as multivariate statistics, applied mathematics, and computer science, in order to address problems in chemistry, biochemistry, medicine, biology and chemical engineering.