Organic Chemistry: Current Research
Open Access
ISSN: 2161-0401
+44 1478 350008
ISSN: 2161-0401
+44 1478 350008
Madhurima Poddar
Indian Institute of Technology Indore, India
Posters & Accepted Abstracts: Organic Chem Curr Res
π Conjugated molecular systems containing sulfur (S) and nitrogen (N) atoms are of significant interest for various optoelectronic applications. A wide variety of S and N based heterocyclic units such as thiazoles, benzothiazoles, benzothiadiazole, phenothiazines and many more have been explored for non-linear optics (NLO), organic light emitting diodes (OLEDs), organic photovoltaics (OPVs) and organic field-effect transistors (OFETs). The incorporation of heterocyclic moiety into the chromophore backbone leads to higher chemical and thermal robustness. Phenothiazine allows variety of reactions including electrophilic substitution at the aromatic position, nucleophilic reaction at the N position, oxidation at the sulfur, etc. Therefore, a series of unsymmetrical (D–A–D1, D1–π–D–A–D1 and D1–A1–D–A2–D1) and symmetrical (D1–A–D–A–D1 ) type of phenothiazines were designed and synthesized by [2 + 2] cycloaddition–electrocyclic ring-opening reaction of ferrocenyl substituted phenothiazines with tetracyanoethylene (TCNE) and 7,7,8,8–tetracyanoquinodimethane (TCNQ). The photophysical, electrochemical and computational studies show strong charge-transfer (CT) interaction in the phenothiazine derivatives which can be tuned by the variation of number of TCNE/TCNQ acceptors. The phenothiazines show red shifted absorption in 400–900 nm region, resulting in low HOMO–LUMO gap which is supported by TD-DFT calculations. The electrochemical study exhibits reduction waves at low potential due to strong 1,1,4,4–tetracyanobuta–1,3–diene (TCBD) and cyclohexa–2,5–diene–1,4–ylidene–expanded TCBD acceptors. The incorporation of cyclohexa–2,5–diene–1,4–ylidene–expanded TCBD stabilizes the LUMO energy level to greater extent as compared to TCBD.