Electron pair, each additional changing

Bases (NH3, C5H5N, C2H5OH, 1,4-dioxane). The basic characteristics of these compoimds can be demonstrated by the addition of a few drops of each to the four yellow solutions obtained in the above experiment. In each solution the color is changed back from yellow to violet on the addition of the base. These compounds are bases because they are electron-pair donors and can form coordinate covalent bonds with the protons of the above-mentioned acids. 

The electronic couplings in DNA r-stacks are very sensitive to conformational changes [31]. CT matrix elements were found to be very responsive to variations in the mutual positions of base pairs. As an example, let us compare the electronic couplings calculated for different conformations of the duplex [(GC),(GC)] (Table 4) [41]. In addition to the reference structure with a base-pair arrangement as in ideal B-DNA, we studied 12 distorted configurations each of them differed from the reference by a single step pa-... 

---