TY - JOUR

T1 - Donor-acceptor coordination of anions by chalcogen atoms of 1,2,5-chalcogenadiazoles

AU - Semenov, N. A.

AU - Lonchakov, A. V.

AU - Gritsan, N. P.

AU - Zibarev, A. V.

PY - 2015/3/1

Y1 - 2015/3/1

N2 - Synthetic, structural, and thermodynamic aspects of the recently discovered new reaction, donor-acceptor coordination of anions (A-) by chalcogen atoms (E) of 1,2,5-chalcogenadiazoles, are considered. According to the quantum chemical calculations, the charge transfer from A- to the heterocycle via the mechanism of negative hyperconjugation (i.e., from the MO of the lone pair of A- to the virtual σorbital of the E - N bond of chalcogenadiazole) depends on the nature of E and A-, being 0.42 - 0.52 and 0.30 - 0.44 e in terms of the Mulliken and NBO methods, respectively. According to the X-ray diffraction data, the E - A- coordinate bond is always longer than the sum of the covalent radii but shorter than the sum of the van der Waals radii of the atoms forming the bond. The E - A- bond energy varies in a wide range, from ~25 kcal mol-1 comparable to the energy of weak covalent bonds (e.g., internal N - N bond in organic azides) to ~86 kcal mol-1 comparable to the C - C bond energy in organic compounds. The quantum chemical estimations of the thermodynamics of the donor-acceptor coordination of the anions by the chalcogen atoms of 1,2,5-chalcogenadiazoles indicate that for E = Te and Se this reaction may be of general character also covering E = S in some cases.

AB - Synthetic, structural, and thermodynamic aspects of the recently discovered new reaction, donor-acceptor coordination of anions (A-) by chalcogen atoms (E) of 1,2,5-chalcogenadiazoles, are considered. According to the quantum chemical calculations, the charge transfer from A- to the heterocycle via the mechanism of negative hyperconjugation (i.e., from the MO of the lone pair of A- to the virtual σorbital of the E - N bond of chalcogenadiazole) depends on the nature of E and A-, being 0.42 - 0.52 and 0.30 - 0.44 e in terms of the Mulliken and NBO methods, respectively. According to the X-ray diffraction data, the E - A- coordinate bond is always longer than the sum of the covalent radii but shorter than the sum of the van der Waals radii of the atoms forming the bond. The E - A- bond energy varies in a wide range, from ~25 kcal mol-1 comparable to the energy of weak covalent bonds (e.g., internal N - N bond in organic azides) to ~86 kcal mol-1 comparable to the C - C bond energy in organic compounds. The quantum chemical estimations of the thermodynamics of the donor-acceptor coordination of the anions by the chalcogen atoms of 1,2,5-chalcogenadiazoles indicate that for E = Te and Se this reaction may be of general character also covering E = S in some cases.

KW - 1,2,5-chalcogenadiazoles

KW - anions

KW - density functional theory

KW - donor-acceptor interactions

UR - http://www.scopus.com/inward/record.url?scp=84947552180&partnerID=8YFLogxK

U2 - 10.1007/s11172-015-0893-7

DO - 10.1007/s11172-015-0893-7

M3 - Article

AN - SCOPUS:84947552180

VL - 64

SP - 499

EP - 510

JO - Russian Chemical Bulletin

JF - Russian Chemical Bulletin

SN - 1066-5285

IS - 3

ER -