Static electric properties of conjugated cyclic ketones and thioketones

Abstract

Articles you may be interested inHow large is the static electric (hyper)polarizability anisotropy in HXeI?The results of ab initio calculations of static electric properties of a series of cyclic conjugated ketones and thioketones are presented. Dipole moments, dipole polarizabilities, as well as the first and second hyperpolarizabilities, were evaluated at different levels of theory: SCF, CASSCF, MP2, CCSD, CCSD͑T͒, and CASPT2 methods were used. Both MP2 and CASPT2 methods have been shown to perform well in the calculation of such properties. The dependence of the electric properties on the extent of the -electron conjugation and on the replacement of the keto by the thioketo group is analyzed. Cyclic conjugated thioketones are shown to exhibit significant nonlinear electric properties which make them prospective building blocks for nonlinear optical materials.

Computational study of keto–enol equilibria of tropolone in gas and aqueous solution phase

“…Other important motivations for the study of tropolone and its derivatives are due to the fact that they are found throughout nature, and a few investigations which have been carried out on these compounds have shown that they exhibit anti-tumour activities [23], phytogrowth inhibitory behaviour [24], and strong insecticidal properties [25]. In addition, considerable theoretical and experimental attention has been placed on the chemical and physical properties of cyclic conjugated ketones [26,27] because of the nonbenzoid aromatic character of three-and seven-membered ring systems, and the anti-aromatic character of five-membered cycles, as well as their potential use as materials with large nonlinear optical properties.…”

Electric properties of formaldehyde, thioformaldehyde, urea, formamide, and thioformamide—Post‐HF and DFT study

“…While formaldehyde belongs to prototypical molecules employed in number of calculations 22 and urea is regarded as medium‐sized reference compound in NLO investigations 23–31, electric dipole moments, polarizabilities, and hyperpolarizabilities of remaining thioformaldehyde 32, formamide 31, 33–35, and thioformamide 33 are rather scarce. There is enough evidence that replacement of the oxygen by the sulfur atom leads to substantial increase of polarizabilities and hyperpolarizabilities 30, 36–38. It could be of interest to compare this amplification when passing from formaldehyde or formamide to their sulfur analogues.…”

Mechanistic Understanding of the Divergent Cyclizations of o‐Alkynylbenzaldehyde Acetals and Thioacetals Catalyzed by Metal Halides

“…The exergonicity for formation of π‐complex B1‐C1 is −15.5 kcal mol −1 , which is quite close to the energy for the formation of A1‐C1 , but the tetracoordinated complexes B1‐C2 and B1‐C3 are much more favorable in comparison with the analogues formed from acetal A1 (Scheme ). This divergence is understandable on the basis of the dipole polarizability of sulfur, which is about 3.5 times larger than that of oxygen;45 thus, the coordination of PtCl 2 to the softer basic sites in B1 is more favorable.…”

“…Havinge stablished the mechanismsf or reactions of acetals with solidt heoretical and experimental evidence, we next explored how the 1,3-dithio-substituted indenesw ere formed from thioacetal derivatives of different alkyne moieties following similar computational procedures.W hen using thioacetal B1,c ontaining am ethyl-substituted alkyne as the model reactant, the formation of B1-C2 from the chelation of PtCl 2 with both sulfur and alkynem oieties is most stable with an exergonicity of À33.1 kcal mol À1 (Scheme 7), whereas the coordination of PtCl 2 to both sulfur atoms to form complex B1-C3 is about 3kcal mol À1 lesss table than the formation of B1-C2.T he exergonicity for formation of p-complex B1-C1 is À15.5 kcal mol À1 , which is quite close to the energy for the formation of A1-C1, but the tetracoordinated complexes B1-C2 and B1-C3 are much more favorable in comparison with the analogues www.chemeurj.org formed from acetal A1 (Scheme 5). This divergence is understandable on the basis of the dipole polarizability of sulfur, which is about3 .5 times larger than that of oxygen; [45] thus, the coordination of PtCl 2 to the softer basic sites in B1 is more favorable.…”