Hydrogen bond accepting

For the group of thirty-three hydrogen-bond-accepting molecules in Table 3.2, we chose to seek correlations directly with the equilibrium constant, K,IB, for 1 1 complexation of... 

The PSA represents a very useful property for predicting absorption. It is usually defined as those parts of the van der Waals or solvent-accessible surface of a molecule that are associated with hydrogen bond-accepting capability (e.g., N or O atoms) and hydrogen bond-donating capability (e.g., NH or OH groups). Three types of PSA have been used in studying absorption ... 

Most hydrogen-bond-containing crystal structures are homomolecular, i.e. both the hydrogen-bond accepting and donating functionality exist in the same molecule. Examples of such co-crystals are urea and thiourea derivatives as well as non-cyclic imides156,179,180. 

Eor the former solvent log D = -1.92 (experimental) vs. -1.98 (calculated) and for the latter log D = 0.76 (experimental) vs. 0.88 (calculated). Obviously, succinic acid with two carboxylic groups that strongly donate hydrogen bonds (assigned a = 1.12 as for acetic acid) prefers the basic (in the Lewis basicity, hydrogen-bond-accepting sense) tri-n-butyl phosphate ( i = 0.82, measured for the wet solvent) over water (P = 0.47) and naturally also chloroform (P = 0.10). 

The type of analyte that can be directly resolved is limited per se, however, they are often specifically derivatized to provide hydrogen bonding/accepting sites. 

Even for a simple reaction, involving just one reactant species and one product species, such as a keto-enol tautomerism or a cis-trans isomerization, the above equation for a given solvent is complicated. StUl, in specific cases it is possible to unravel the solvent effects of cavity formation, for the solute species have different volumes, polarity/polarizability if the solute species differ in their dipole moments or polarizabilities, and solvent Lewis acidity and basicity if the solutes differ in their electron-pair and hydrogen-bond acceptance abilities. 

Most reactive impurities are acids or bases in a broad sense. Here, an acid is a substance that has proton donor capacity, hydrogen bond donor capacity, electron pair acceptability, and electron acceptability. A base is a substance that has proton acceptability, hydrogen bond acceptability, electron pair donor capacity and electron donor capacity. Some reactive impurities have both acidic and basic properties. 

Polarizability-Kow Relationships Molar polarizabilities can be derived from molecular orbital (MO) calculations by the complete neglect of differential overlap (CNDO) method [42]. The following correlation has been found for polar compounds that contain either hydrogen-bond-accepting or hydrogen-bond-donating groups (alkanols, alkanones, dialkyl ethers, alkanenitriles) ... 

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