A theoretical evaluation of the pKHB and ΔH–HB hydrogen-bond scales of nitrogen bases was written by Besseau, Francois;Graton, Jerome;Berthelot, Michel. And the article was included in Chemistry – A European Journal in 2008.Safety of 2-Isopropylpyridine This article mentions the following:
The exptl. pKHB hydrogen-bond (HB) basicity scale and the corresponding ΔH–hB enthalpic scale of nitrogen compounds are extended and analyzed in light of simple theor. descriptors using the B3LYP d. functional method and a medium-size basis set (6-31 + G(d,p)). The selected training set includes 59 monofunctional unhindered nitrogen bases for which homogeneous and accurate exptl. pKHB and ΔH–HB data have been determined by means of the association equilibrium of the bases with a reference hydrogen-bond acid, 4-fluorophenol, in CCl4. The three hybridization states encountered in the nitrogen atom, sp, sp2 and sp3, are equally represented in this data set. A proper estimation of their exptl. enthalpy (ΔH–HB) is directly attainable from the theor. enthalpy of the complexation reaction with hydrogen fluoride (ΔH-(HF)). However, a second parameter is required to calculate with good accuracy the exptl. free energy of association represented by pKHB. About 99% of the variance of the pKHB scale is described by a bilinear equation using the min. electrostatic potential (VS,min) of the monomer in addition to the interaction energy (D(HF)0). The equations are tested for an external set of 99 addnl. compounds including very different nitrogen bases such as ortho-substituted pyridines, polyazines and azoles. Theor. calculations give a reliable estimation of hydrogen-bond basicity provided that the populations of the different isomers of the bases are taken into account by using the Boltzmann law, and that a specific halogen-bond interaction with the solvent CCl4 is considered for polybasic mols. The pKHB scale can thus be extended to important classes of species exptl. inaccessible in CCl4, to polynitrogen compounds and to mols. of biol. significance. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4Safety of 2-Isopropylpyridine).
2-Isopropylpyridine (cas: 644-98-4) belongs to pyridine derivatives. Pyridines are an important class of heterocycles and occur in polysubstituted forms in many naturally occurring biologically active compounds, drug molecules and chiral ligands. Pyridine, its benzo and pyridine-based compounds play diverse roles in organic chemistry. Pyridine-based materials are valued for their optical and physical properties as well as their medical potential. Safety of 2-Isopropylpyridine