Molecular polarity predicting

Predict relative solubilities from molecular polarity (Section 8.9). 

Ertl P, Rohde B, Selzer P. Fast calculation of molecular polar surface area as a sum of fragment-based contributions and its application to the prediction of drug transport properties. I Med Chem 2000 43 3714-7. 

Predicting and sketching molecular shapes Predi cting and explaining bond angles Identifying molecular polarity... 

A molecule is considered to be polar, or to have a molecular polarity, when the molecule has an overall imbalance of charge. That is, the molecule has a region with a partial positive charge, and a region with a partial negative charge. Surprisingly, not all molecules with polar bonds are polar molecules. For example, a carbon dioxide molecule has two polar C=0 bonds, but it is not a polar molecule. On the other hand, a water molecule has two polar O—H bonds, and it is a polar molecule. How do you predict whether or not a molecule that contains polar bonds has an overall molecular polarity To determine molecular polarity, you must consider the shape of the molecule and the bond dipoles within the molecule. 

Note For the purpose of predicting molecular polarity, you can assume that C—H bonds are non-polar. In fact, they have a very low polarity. 

Use your knowledge of molecular shape and polar bonds to predict whether each molecule has an overall molecular polarity. 

Look back at Chapter 1, pages 8-10, to review howto predict the molecular polarity of organic compounds. 

A similar polar cyclization of an enamine and a thioketene derivative is shown in equation (87) (76TL4283), but electron-deficient alkenes and alkynes react in a concerted fashion. Concerted cyclizations may be subdivided into those in which the sulfur atom is part of the enophile or the dienophile. Into the first category fall the dimerizations of a,( - unsaturated thioaldehydes (equation 88) which may be shown to closely follow frontier molecular orbital predictions of regioselectivity (79JOC486). Related to this are the thiochalcones (equation... 

The most interesting feature of Fig.3 is the sharp peak in the weight of the metallic structures around 1.7 A. Each metallic structure has two polarized H2 molecules as a result of the transfer from a molecular valence bond to a new bond to a neighbor molecule (Fig.2). Our results therefore support a hypothesis, previously made [20], that the ground state wave function will have a component of charge-transfer states at pressures around 150 GPa. Moreover, our results indicate that small variations of the intermolecular separation around 1.7 A (as a result of a structural modification, for instance) can induce sizeable changes in the polarization of the H2 molecules. This is fully consistent with the spontaneous polarization predicted by Edwards and Ashcroft [21], and it provides an explanation for this phenomenon in terms of the chemical bonding in the solid. 

Use Lewis structures to predict the molecular polarities for sulfur difluoride, sulfur tetrafluoride, and sulfur hexafluoride. 

When all central atoms in the molecule or ion have been accounted for, use the entire molecular geometry, electronegativity differences, and the presence of lone pairs of valence shell electrons on the central atom to predict molecular polarity (Section 8-3 parts B of Sections 8-5 through 8-12). 

Molecular property prediction is becoming a useful tool in the generation of libraries of beautiful molecules, or molecules with the correct parameters to be useful drug candidates. Used in a more focused way, drug design and lead optimization benefits from an ability to predict physical properties such as lipophilicity and solubility, as well as physical molecular properties such as polar molecular... 

Predict molecular polarity from three-dimensional geometry and bond polarity. 

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