عنوان
|
Characterization of r-hole interactions in 1:1 and 1:2 complexes
of YOF 2 X (X 5 F, Cl, Br, I; Y 5 P, As) with ammonia:
competition between halogen and pnicogen bonds
|
چکیده
|
Ab initio calculations at the MP2/aug-cc-pVTZ
level of theory are performed to examine 1:1 and 1:2
complexes of YOF 2 X (X = F, Cl, Br, I; Y = P, As) with
ammonia. The YOF 2 X:NH 3 complexes are formed through
the interaction of the lone pair of the ammonia with the r-
hole region associated with the X or Y atom of YOF 2 X
molecule. The calculated interaction energies of halogen-
bonded complexes are between -1.06 kcal/mol in the
POF 3 NH 3 and -6.21 kcal/mol in the AsOF 2 INH 3 one.
For a given Y atom, the largest pnicogen bond interaction
energy is found for the YOF 3 , while the smallest for the
YOF 2 I one. Almost a strong linear relationship is evident
between the interaction energies and the magnitudes of the
positive electrostatic potentials on the X and Y atoms. The
results indicate that the interaction energies of halogen and
pnicogen bonds in the ternary H 3 N:YOF 2 X:NH 3 systems
are less negative relative to the respective binary systems.
The interaction energy of YN bond is decreased by
1–22 %, whereas that of XN bond by about 5–61 %.
That is, both YN and XN interactions exhibit antico-
operativity or diminutive effects in the ternary complexes.
|