The hetero-Friedel-Crafts-Bradsher Cyclizations with Formation of Ring Carbon-Heteroatom (P, S) Bonds, Leading to Organic Functional Materials

The interest in functional materials possessing improved properties led to development of new methods of their synthesis, which allowed to obtain new molecular arrangements with carbon and heteroatom motifs. Two of the classical reactions of versatile use are the Friedel-Crafts and the Bradsher reactions, which in the new heteroatomic versions allow to replace ring carbon atoms by heteroatoms. In the present work, we review methods of synthesis of C–S and C–P bonds utilizing thia- and phospha-Friedel-Crafts-Bradsher cyclizations. Single examples of C–As and lack of C–Se bond formation, involving two of the closest neighbors of P and S in the periodic table, have also been noted. Applications of the obtained π-conjugated molecules, mainly as semiconducting materials, flame retardants, and resins hardeners, designed on the basis of five- and six-membered cyclic molecules containing ring phosphorus and sulfur atoms, are also included. This comprehensive review covers literature up to August 2020.

The influence of external electric fields on charge reorganization energy in organic semiconductors

Charge reorganization energies (λ) of inter-ring carbon–carbon (IRCC) bond connected conjugated polycyclics are shown to exhibit an electric-field-driven anisotropic character.

Unconventional ionic ring-deconstruction pathways of a three-membered heterocycle

Two different ionic deconstruction reactions of the oxaphosphirane ring in I are reported. One is induced by base and involves displacement of the aldehyde unit forming II whilst acid-initiated extrusion of the ring-carbon with its substituents yielded III. Further insights into the latter ring-deconstruction were obtained by quantum chemical calculations.

SEQUENTIAL SUBSTITUTION OF METHYL SIDE GROUP IN NAPTHOQUINONE AND ANTHRAQUINONE TO INVESTIGATE SENSITIVITY OF THE CARBONYL BAND

In this work, we have added methyl side group (s) on quinone and aromatic ring carbon positions of 1, 4-naphthoquinone (NQ) and on aromatic ring carbon positions of 1, 4-anthraquinone (AQ) in sequential increasing order to check sensitivity of the carbonyl band. In NQ, we observed that the aromatic substitution is more sensitive than the quinonic substitution. In fact, the sequential addition of CH3on the quinone ring C5 and C6 positions lead into the systematic lowering of the band and such lowering is in average of 5 cm-1 per methyl group. On the other hand, addition on the aromatic ring C7, C8, C9, and C10 positions resulted in mix effect. Indeed, they produce two types of carbonyl band, which are couple and uncouple. For further exploration of the sensitivity of the carbonyl band, we put single or two methyl group (s) on C7, C8, C9, and C10 carbon positions producing four or six NQ model molecules. We concluded that the carbonyl intense bands are more sensitive, split up, to the aromatic ring methyl substitution at C7 or C10 position. Furthermore, in AQ couple mode of C=O vibration was observed and no splitting of the band was seen on sequential CH3 addition.Journal of Institute of Science and TechnologyVolume 22, Issue 1, July 2017, Page: 137-146