چکیده
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A r-hole is defined as an electron-deficient
region on the extension of a covalently bonded group IV–
VII atoms. If the electronic density in the r-hole is suffi-
ciently low, then this region will have a positive electro-
static potential, which allows attractive noncovalent
interactions with negative sites. SO 2 X 2 and SeO 2 X 2
(X = F, Cl and Br) have three Lewis acid sites of r-hole
located in the outermost of chalcogen atom and X end,
participating in the chalcogen and halogen bonds with NH 3
and H 2 O, respectively. MP2/aug-cc-pVTZ and M06-2X/
aug-cc-pVTZ calculations reveal that for a given halogen
atom, SeO 2 X 2 forms stronger chalcogen bond interactions
than SO 2 X 2 counterpart. Almost a perfect linear relation-
ship is evident between the interaction energies and the
magnitudes of the product of most positive and negative
electrostatic potentials. The interaction energies calculated
by M06-2X and MP2 methods are almost consistent with
each other.
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