Theoretical study of O - > X (S, Se, Te) coordination in organic compounds

Abstract

Ab initio (RHF/LanL2DZ, MP2(fc)/LanL2DZ, MP2(fc)/6-31G**, and MP2(fc)/6-311++G**) calculations were performed for a series of β -chalcogenovinylaldehydes, 1,6-dioxa-6a-chalcogenopentalenes, and bimolecular complexes of formaldehyde with chalcogen hydrides and chlorides. The calculations reproduce well the existence and experimentally observed structural peculiarities of the intra- and intermolecular Ο - > chalcogen attractive interactions that stabilize the hypervalent T-shaped bond configuration at a chalcogen atom. These interactions increase in the order S, Se, Te and with the increasing electronegativity of a substituent attached to the chalcogen center. The ab initio calculations performed predict the existence of sufficiently stable bimolecular complexes H2CO . . .XR1R2 (X = S, Se, Te; R1, R2 = H, Cl) with a complexation energy comparable to the energy of a strong hydrogen bond.Key words: ab initio calculations, chalcogen-containing compounds, intramolecular coordination.

Regioselective synthesis, structure and behavior in solutions of novel phosphorylated thiazolidin‐4‐ones

“…1, Table 1) are close to the typical values for thizolidine-4-one derivatives [6,7,[11][12][13]. In particular, the thiazolidin-4-one cycle is planar and both C(2) C(8) and C(5) C(6) bond lengths are equal to 1.344(4)Å.…”

“…The latter type of intramolecular interaction is also typical for the thiazolidin-4-one derivatives [6,7,11]. The nature of the such X S· · ·O contacts is usually explained in terms of the charge transfer from the oxygen lone pair (Lp O ) to the antibonding orbital of the X S bond ( * X S ) [12,13] which is in line with the specific direction of this contact in 3a [C(2)S(1)O (5) is 164.8 (2) • ]. However, the S(1)· · ·O(5) contact (2.800(2)Å) in 3a-E,Z is significantly elongated in comparison with the ones in nonphosphorylated thiazolidin-4-one derivatives (2.613-2.696Å) known in the literature [11,[14][15][16].…”

The Role of Intramolecular Hydrogen Bonds vs. Other Weak Interactions on the Conformation of Hyponitrous Acid and Its Mono- and Dithio-Derivatives

“…In some specific cases, other weak interactions, such as chalcogen-chalcogen interactions [13] in β-chalcogenvinylaldehydes, compete in strength with IHB's [14]. As a matter of fact, in HC( O) CH CH TeH, the O · · · Te H intramolecular interaction, that can be viewed as dative bond from the oxygen lone-pair toward the σ * Te−H antibonding orbital [14], is much more stabilizing than the corresponding O H · · · Te or O · · · H Te IHB's.…”

Synthesis and structure of N-arylimines of β-tellurocyclohexenals with the intramolecular coordination N→Te bonds

“…Chalc bonds existing in the appropriately functionalized organochalcogen compounds [1,[7][8][9][10][11][12]. According to the estimates based on ab initio and DFT quantum chemical calculations [11,12] and dynamic NMR studies [10,13] the energies of these bonds cover the wide range of values between 20 and 125 kJ mol À1 . The largest values approach those of a covalent bond and characterize the intramolecular coordination O(N) !…”