electron density calculated at the carbon atom increases). For example, the HCCX
halogen derivatives of acetylene were analyzed and it was found that the maximum
EP at X center is equal to +2.3, +20.4 and +27.0 kcal/mol for X = F, Cl and Br,
respectively (B3PW92/6-31G(d,p) level of calculations) [34]. There are similar
findings of an increase of the positive EP for heavier X-center for other species, like
for example H 3 CX, F 3 CX or C 6 H 5 X [34].
Figure 15.6 presents the molecular graphs of HCCCl and HCCBr molecules with
the isolines of the laplacian of electron density. One can see the anisotropic
Fig. 15.6 The molecular graphs of the HCCCl (up) and HCCBr (down) molecule, solid and
broken lines correspond to bond paths, big circles to attractors and small green circles to BCPs,
the isolines of Laplacian of electron density are also presented
408
S.J. Grabowski
halogen derivatives of acetylene were analyzed and it was found that the maximum
EP at X center is equal to +2.3, +20.4 and +27.0 kcal/mol for X = F, Cl and Br,
respectively (B3PW92/6-31G(d,p) level of calculations) [34]. There are similar
findings of an increase of the positive EP for heavier X-center for other species, like
for example H 3 CX, F 3 CX or C 6 H 5 X [34].
Figure 15.6 presents the molecular graphs of HCCCl and HCCBr molecules with
the isolines of the laplacian of electron density. One can see the anisotropic
Fig. 15.6 The molecular graphs of the HCCCl (up) and HCCBr (down) molecule, solid and
broken lines correspond to bond paths, big circles to attractors and small green circles to BCPs,
the isolines of Laplacian of electron density are also presented
408
S.J. Grabowski