NIR-Absorbing TCBD and Expanded TCBD-Functionalized Ferrocene–Phenothiazine Conjugates Nikhil Ji Tiwari, Deeksha Gupta, Rajneesh Misra Organometallics, 2026 A set of TCBD- and expanded TCBD-functionalized donor–acceptor ferrocene conjugates Fc2–3 and Fc5–6 were designed and synthesized via Pd-catalyzed Sonogashira cross-coupling, followed by [2 + 2] cycloaddition–retroelectrocyclization reactions. Phenothiazine (PTZ) and ferrocene (Fc) were used as the terminal donor units. The incorporation of cyano-based strong acceptors 1,1,4,4-tetracyanobutadiene (TCBD) and dicyanoquinodimethane (DCNQ) in the ferrocene and ferrocene–phenothiazine conjugates resulted in substantial variation in their photophysical, electrochemical, and thermal behavior. The electronic absorption spectra of the ferrocene derivatives with TCNE ( Fc2, Fc5 ) and TCNQ ( Fc3, Fc6 ) acceptors show bathochromically shifted absorption compared to Fc1 and Fc4 due to a significant intramolecular charge-transfer (ICT) transition. The electrochemical analysis of Fc2–3 and Fc5–6 reveals reduction waves at lower potentials due to the TCBD and DCNQ acceptors. The TCBD-functionalized ferrocene derivative Fc2 shows higher thermal stability compared to other ferrocene conjugates. DFT-optimized geometries and frontier orbital energies of Fc1–6 indicate that increasing the acceptor strength stabilizes the LUMO and reduces the HOMO–LUMO gap. The spectroelectrochemical analyses of Fc2–3 and Fc5–6 revealed substantial spectral changes during the reduction cycle in the NIR region, whereas Fc1 and Fc4 displayed changes during the oxidation cycle in the NIR region.
Charge Carrier Mobility of Phenothiazine Functionalized TCBD Derivatives of Naphthalimide Nikhil Ji Tiwari, Tarun, Upendra Kumar Pandey, Rajneesh Misra Chemistry an Asian Journal, 2026 A set of naphthalimide functionalized push–pull chromophores NPI 1–3 were designed and synthesized via Pd‐catalyzed Sonogashira cross‐coupling followed by [2 + 2] cycloaddition‐electrocyclic ring‐opening reaction. The 1,8‐naphthalimide (NPI) and 1,1,4,4‐tetracyanobuta‐1,3‐diene (TCBD) moiety acts as an acceptor unit, whereas phenothiazine (PTZ) unit acts as a donor unit. Their photophysical, electrochemical properties, and charge carrier mobilities were investigated. Density functional theory (DFT) and TD‐DFT calculations were performed on NPI 1–3 to analyze the molecular geometry, frontier molecular orbitals, molecular electrostatic potentials (MEPs), and electronic transitions related to their absorption spectra. The incorporation of cyano‐based strong electron acceptor TCBD in the phenothiazine functionalized naphthalimide derivatives NPI1 resulted in TCBD incorporated chromophore NPI 2–3 which exhibits red‐shifted electronic absorption spectra in the near IR region. The electrochemical properties reveal that the naphthalimide derivatives NPI 1–3 exhibit multiple redox waves, attributed to the presence of NPI and TCBD acceptor units and phenothiazine donor units. The measured hole and electron mobilities for NPI 1–3 are 4.06 × 10 −3 and 3.16 × 10 −3 cm 2 V −1 s −1 , 7.5 × 10 −3 and 4.48 × 10 −3 cm 2 V −1 s −1 , 6.76 × 10 −3 and 3.1 × 10 −3 cm 2 V −1 s −1 , respectively, obtained by space‐charge limited current (SCLC) measurements.
Boosting the Efficiency of Red Thermally Activated Delayed Fluorescence via Conjugation Enhancement in Push-Pull Naphthalimide Derivatives Chiara Montanari, Nikhil Ji Tiwari, Rajneesh Misra, Benedetta Carlotti Chemistry A European Journal, 2024 In this work, we synthesize a series of push–pull compounds bearing naphthalimide as the electron acceptor and tetraphenylethylene (TPE)/triphenylamine (TPA)/phenothiazine (PTZ) as the electron rich/electron donor units. These moieties are arranged in highly conjugated quadrupolar structures. The structure–property relationships are investigated through a joint experimental time–resolved spectroscopic and computational TD–DFT study. The femtosecond transient absorption and fluorescence up–conversion experiments reveal ultrafast photoinduced intramolecular charge transfer. This is likely the key factor leading to efficient spin–orbit CT–induced intersystem crossing for the TPA– and PTZ–derivatives as well as to small singlet–to–triplet energy gap. Consequently, evidence for a delayed fluorescence component is found together with the main prompt emission in the fluorescence kinetics both in solution and in thin film. The weight of the Thermally Activated Delayed Fluorescence (TADF) is greatly enhanced when these fluorophores are used as guests in solid–state host matrices. TADF is interestingly revealed in the orange–red region of the visible. Such long wavelength emission is here observed with surprisingly large fluorescence quantum yields, thanks to the conjugation enhancement achieved in these newly synthesized structures relative to previous studies. Our findings may be thus promising for the future development of efficient third generation TADF–based OLEDs.
Near-IR absorbing 1,1,4,4-tetracyanobutadiene-functionalized phenothiazine sulfones Manju Sheokand, Nikhil Ji Tiwari, Rajneesh Misra Organic and Biomolecular Chemistry, 2023 Triphenylamine (TPA) substituted π-conjugated chromophores TPA1–TPA5 were designed and synthesized, and the DCNQ incorporated ones exhibited bathochromically shifted broad absorption in the NIR region and a better D–A interaction than the TCBD functionalized ones.
RECENT SCHOLAR PUBLICATIONS
Tetracyanobutadiene-and Dicyanoquinodimethane-Benzothiadiazole Push–Pull Systems: The Role of Terminal Electron Donors in Governing Intramolecular Charge Transfer Y Rout, S Sikka, P Pureti, NJ Tiwari, S Das, R Misra, F D’Souza The Journal of Physical Chemistry C , 2026 2026
NIR-Absorbing TCBD and Expanded TCBD-Functionalized Ferrocene–Phenothiazine Conjugates NJ Tiwari, D Gupta, R Misra Organometallics 45 (8), 992-1005 , 2026 2026 Citations: 1
Charge Carrier Mobility of Phenothiazine Functionalized TCBD Derivatives of Naphthalimide NJ Tiwari, Tarun, UK Pandey, R Misra Chemistry–An Asian Journal 21 (5), e00259 , 2026 2026 Citations: 3
Ferrocenyl-functionalized phenothiazine conjugates: structure–property relationship and electrochemical energy storage studies D Gupta, NJ Tiwari, V Kandpal, PP Singh, R Misra New Journal of Chemistry 50 (1), 282-293 , 2026 2026 Citations: 1
Controlling the spatial distribution of electronic excitation in asymmetric D–A–D′ and symmetric D′–A–D–A–D′ electron donor–acceptor molecules E Balanikas, T Bianconi, P Mancini, NJ Tiwari, M Sheokand, R Misra, ... Chemical Science 16 (19), 8443-8453 , 2025 2025 Citations: 12
Design, synthesis, and redox properties of donor–π–donor ferrocenyl functionalized phenothiazine derivatives D Gupta, NJ Tiwari, PP Singh, R Misra Dalton Transactions 54 (14), 5906-5920 , 2025 2025 Citations: 5
Design, synthesis, and redox properties of ferrocene-functionalized phenothiazine and phenothiazine sulfone isomers NJ Tiwari, R Misra Dalton Transactions 54 (10), 4366-4379 , 2025 2025 Citations: 7
Boosting the Efficiency of Red Thermally Activated Delayed Fluorescence via Conjugation Enhancement in Push‐Pull Naphthalimide Derivatives C Montanari, N Ji Tiwari, R Misra, B Carlotti Chemistry–A European Journal 30 (57), e202402294 , 2024 2024 Citations: 8
Controlling the spatial distribution of electronic excitation in asymmetric D–A–D′ and symmetric D′–A–D–A–D′ electron donor–acceptor molecules E Balanikas, T Bianconi, P Mancini, NJ Tiwari, M Sheokand, R Misra, ... Chemical Science 16 (19), 8443-8453 , 2025 2025 Citations: 12
Boosting the Efficiency of Red Thermally Activated Delayed Fluorescence via Conjugation Enhancement in Push‐Pull Naphthalimide Derivatives C Montanari, N Ji Tiwari, R Misra, B Carlotti Chemistry–A European Journal 30 (57), e202402294 , 2024 2024 Citations: 8
Design, synthesis, and redox properties of ferrocene-functionalized phenothiazine and phenothiazine sulfone isomers NJ Tiwari, R Misra Dalton Transactions 54 (10), 4366-4379 , 2025 2025 Citations: 7
Design, synthesis, and redox properties of donor–π–donor ferrocenyl functionalized phenothiazine derivatives D Gupta, NJ Tiwari, PP Singh, R Misra Dalton Transactions 54 (14), 5906-5920 , 2025 2025 Citations: 5
Charge Carrier Mobility of Phenothiazine Functionalized TCBD Derivatives of Naphthalimide NJ Tiwari, Tarun, UK Pandey, R Misra Chemistry–An Asian Journal 21 (5), e00259 , 2026 2026 Citations: 3
NIR-Absorbing TCBD and Expanded TCBD-Functionalized Ferrocene–Phenothiazine Conjugates NJ Tiwari, D Gupta, R Misra Organometallics 45 (8), 992-1005 , 2026 2026 Citations: 1
Ferrocenyl-functionalized phenothiazine conjugates: structure–property relationship and electrochemical energy storage studies D Gupta, NJ Tiwari, V Kandpal, PP Singh, R Misra New Journal of Chemistry 50 (1), 282-293 , 2026 2026 Citations: 1
Tetracyanobutadiene-and Dicyanoquinodimethane-Benzothiadiazole Push–Pull Systems: The Role of Terminal Electron Donors in Governing Intramolecular Charge Transfer Y Rout, S Sikka, P Pureti, NJ Tiwari, S Das, R Misra, F D’Souza The Journal of Physical Chemistry C , 2026 2026
