Heteroatom and solvent effects on molecular properties of formaldehyde and thioformaldehyde symmetrically disubstituted with heterocyclic groups C4H3Y (where Y = O–Po)

Abstract

In this work several molecular properties of symmetrically disubstituted formaldehyde and thioformaldehyde have been studied using a quantum chemistry approach based on density functional theory. Five-membered heteroaromatic rings containing a single group 16 heteroatom were taken into account as the substituents (i.e., furan-2-yl, thiophen-2-yl, selenophen-2-yl, tellurophen-2-yl, and the experimentally as yet unknown polonophen-2-yl). For the resulting ten formaldehyde and thioformaldehyde derivatives, the geometry, energetics, frontier molecular orbitals, dipole moment and polarizability of their molecules were examined in order to establish the effect of ring heteroatom on these properties. Furthermore, these properties were also determined for the molecules in three solvents of low polarity (benzene, chloroform, and dichloromethane) in order to expand our study to include solvent effects. The dipole moment and polarizability of the investigated molecules show regular variations when the ring heteroatom descends through group 16 and the solvent polarity grows. The heteroatom and/or solvent effects on the part of the studied properties are, however, more complex. An attempt is made to rationalize the observed variations in the molecular properties. The conformational behavior of the investigated molecules was also explored and the conformationally weighted values of dipole moment and polarizability are presented. Graphical abstractSome molecular properties of symmetrically disubstituted formaldehyde and thioformaldehyde Electronic supplementary materialThe online version of this article (doi:10.1007/s00894-017-3435-4) contains supplementary material, which is available to authorized users.

Ferrocenyl hetaryl thioketones: A computational study of their conformational stability

“…Conformations III and IV exhibit s‐ trans ‐like arrangements of their S1 and X atoms. The preference of the s‐ cis ‐like arrangement of S1 and X in 2 ‐ 4 is in line with their arrangement detected previously for dihetaryl thioketones . The Δ E values for 1 ‐ 4 reveal that their preferred and second most energetically favorable geometries were a pair of either s‐ cis ‐like or s‐ trans ‐like conformers.…”

“…The previous paragraph emphasized the effect of molecular structure on the potential medical application of functionalized thioketones and this additionally motivated us to study the conformational stability of 1 ‐ 5 . It should be stressed that the present work is a continuation of our previous computational studies devoted to dihetaryl thioketones possessing the aforementioned hetaryl substituents …”

“…The preference of the s-cis-like arrangement of S1 and X in 2-4 is in line with their arrangement detected previously for dihetaryl thioketones. [19][20][21][22] The ΔE values for 1-4 reveal that their preferred and second most energetically favorable geometries were a pair of either s-cis-like or s-trans-like F I G U R E 3 One-dimensional relaxed scans of the potential energy surface of 1 in three initial conformations (τ Het = 20 , 190 , and 340 ) plotted against the dihedral angle describing the internal rotation within the Fc substituent (τ Cp , in ). The energy (ΔE, in kcal mol −1 ) is expressed relative to the corresponding lowestenergy conformations.…”

“…It should be stressed that the present work is a continuation of our previous computational studies devoted to dihetaryl thioketones possessing the aforementioned hetaryl substituents. [19][20][21][22] 2 | COMPUTATIONAL DETAILS For thioketones 1-5, a great number of their initial geometries showing various arrangements of Fc and Het/Ph substituents and cyclopentadienyl (Cp) rings within the Fc substituent were optimized at the B3LYP/def2-TZVP level of theory [23][24][25][26][27] to detect their possible conformations. All conformers found were reoptimized using a more extended basis set, that is, def2-QZVPP.…”

Structure of Diferrocenyl Thioketone: From Molecule to Crystal

“…From a theoretical perspective based on quantum-chemical calculations, Fc 2 CS has not been explored at all. This is not surprising because the theoretical studies of thioketones bearing a single Fc-group or even two (het)aryl groups are very scarce [26,27,28,29,30]. The aforementioned gaps in the experimental and theoretical characterization of Fc 2 CS have motivated us to obtain part of the missing information about this exceptional thioketone.…”