The first example of a Y-shaped ferrocene quinoxaline derivative with high and stable SHG response in polymeric films is reported.

Senthil Kumar K

Department of Computer Applications

School of Information Technology and Engineering

Vellore Campus

Thirumoorthy K

Department of Chemistry

School of Advanced Sciences

Palanisami N

Dragonetti C

Marinotto D

Righetto S

Colombo A

Haukka M

Fulltext

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

&nbsp;

&nbsp;

VIT University

Dalton Transactions

The donor-π-acceptor ferrocene conjugated malononitrile dimer [C5H5–Fe–C5H4–C(H)[dbnd]C(CN)–C(NH2) = C(CN)2] (1) has been synthesized and characterized with the aid of analytical and spectroscopic techniques [FT-IR, GC-Mass, 1H and 13C NMR]. The thermal stability of the compound 1 was investigated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA), exhibit the compound is stable up to 180 °C. The photophysical properties were performed by UV–visible and fluorescence spectroscopic methods and the compound 1 exhibited weak fluorescence emission. In addition, the optical band gap (Eg) was calculated using diffused reflectance spectroscopic technique which shows the band gap value of Eg = 3.6 eV. The redox wave of the compound 1 was determined by cyclic voltammetry, revealed that one electron transfer ability of the ferrocene to ferrocenium ion. The experimentally observed HOMO and LUMO values are good agreement with the theoretical calculation by DFT-M06 method using 6–31 + G** as basis set. The solvatochromic studies of compound 1 shows negative solvatochromism due to the high ground state polarizability in presence of cyano acceptors. Further, the nonlinear optical properties were investigated by Q-switched Nd-YAG laser and second harmonic generation efficiency (SHG) using para-nitroaniline (p-NA) as a standard and the results of SHG efficiency is 0.35 times comparable with p-NA. © 2019 Elsevier B.V.

Journal of Molecular Structure

Ferrocene conjugated donor-π-acceptor malononitrile dimer: Synthesis, theoretical calculations, electrochemical, optical and nonlinear optical studies

New Y-shaped ferrocene and non-ferrocene conjugated quinoxaline derivatives {[R-(CH)2-N=CH-)2C10H4], R = C5H5-Fe-C5H5 (1) and R = C6H4-OCH3 (2)} have been synthesized and characterized using analytical and spectroscopic techniques. The thermal stability of the compounds 1 and 2 were examined by thermogravimetric analysis (TGA), both were stable up to 250 °C. The optical properties were studied using UV–Visible and fluorescence spectroscopic methods and Y-shaped ferrocene appended quinoxaline derivative 1 show a weak emission due to the quenching nature of ferrocene. The compound 2 shows enhanced fluorescence intensity in their aggregation state due to Restricted Intramolecular Rotation (RIR). Hence, the compound 2 have further utilized for the detection of picric acid (PA) by fluorimetric method and the detection limit of 1.37 × 10−6 M was obtained. Further, paper sensor was made using compound 2 which resulted in the instant ‘naked eye’ response for trace detection of picric acid. Consequently, the compound 2 acts as a colorimetric sensor and can be used as a new probe for the detection of nitro aromatic explosives. © 2019 Elsevier B.V.

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy

Y-shaped ferrocene/non-ferrocene conjugated quinoxalines for colorimetric and fluorimetric detection of picric acid

N-Arylated bisferrocene pyrazoles for the dual-mode detection of H2O2 by AIE-active fluorescence and non-enzymatic electrochemical methods.

New Journal of Chemistry

N-Arylated bisferrocene pyrazole for the dual-mode detection of hydrogen peroxide: an AIE-active fluorescent “turn ON/OFF” and electrochemical non-enzymatic sensor

New ferrocenyl Schiff bases [Fc─C(H)═N─C6H3(OH)(R)] (R = H (1), NO2 (2)) have been synthesized and characterized using various techniques. Compound 2 was further confirmed using single-crystal X-ray diffraction analysis. Solvatochromism studies of 2 showed redshift from nonpolar to polar solvents. In addition, results of fluorescence studies indicated excellent aggregation-induced emission properties. The quasi-reversible redox wave in electrochemical studies of the Schiff bases evidenced the electron transfer ability of ferrocene to the Schiff base (─C═N─) conjugation group. The second-order nonlinear optical (NLO) properties of 1 and 2 were investigated using the Kurtz–Perry powder technique and 2 showed an effect 1.46 times greater than that of urea reference. Although 2 crystallized in the P21/c centrosymmetric space group, NLO property was observed, due to non-covalent interactions (C─H⋅⋅⋅π). The band gaps were calculated using the diffuse reflectance spectroscopic method and 2 exhibited a low band gap of 2.9 eV which is due to the more electron-withdrawing nature of the nitro group. Quantum chemical calculations were performed on the synthesized compounds using the density functional theory (DFT) and time-dependent DFT approach. The theoretical studies showed that the band gap for the Schiff bases was 3.8 eV (1) and 3.2 eV (2) and they can be considered as candidates for use in optical applications. © 2018 John Wiley & Sons, Ltd.

Applied Organometallic Chemistry

Ferrocene-appended donor-π-acceptor Schiff base: Structural, nonlinear optical, aggregation-induced emission and density functional theory studies

A series of new N-arylated ferrocenepyrazole structures, carrying different donor or acceptor substituents in the para position of the aryl ring, has been synthesized by the Chan–Lam cross-coupling reaction. The nonplanar geometric molecular structure of some of these chromophores together with their crystal packing was determined by X-ray diffraction, and the HOMO and LUMO energy levels were evaluated by electrochemical and optical measurements and by density functional theoretical (DFT) calculations. By the investigation of solvent effects and time-dependent DFT (TD-DFT) calculations, the intense electronic absorption band around 270–310 nm was confirmed to be an internal-charge-transfer (ICT) band, showing a significant red shift by increasing the electron withdrawing properties of the substituent on the para position of the aryl ring. TD-DFT calculations and electric field induced second harmonic generation (EFISH) measurements of the quadratic hyperpolarizability have shown that also the second-order nonlinear optical (NLO) response of these new ICT chromophores can be tuned by changing the nature of the substituent. Both theoretical μβ and β and experimental EFISH μβ1907 and β1907 values are significant, with a quite satisfactory correlation of the general trend of theoretical μβ and EFISH μβ1907 values. The highest value of EFISH μβ1907 (410 × 10–48 esu) was measured for the chromophore carrying the strong electron withdrawing NO2 group.

The Journal of Physical Chemistry C

New Internal-Charge-Transfer Second-Order Nonlinear Optical Chromophores Based on the Donor Ferrocenylpyrazole Moiety

Optical and Quantum Electronics

Optoelectronic features of Y-shaped push–pull molecules based on imidazole

European Journal of Organic Chemistry

T-Shaped (Donor-π-)2Acceptor-π-Donor Push-Pull Systems Based on Indan-1,3-dione

European Journal of Inorganic Chemistry

Dye-Sensitized Solar Cells with Biferrocenyl Antennae Having Quinoxaline Spacers

ACS Applied Materials & Interfaces

Cosensitization of D-A-π-A Quinoxaline Organic Dye: Efficiently Filling the Absorption Valley with High Photovoltaic Efficiency

Journal of Materials Chemistry C

Highly efficient acido-triggered reversible luminescent and nonlinear optical switch based on 5-π-delocalized-donor-1,3-di(2-pyridyl)benzenes

Ferrocene–quinoxaline Y-shaped chromophores as fascinating second-order NLO building blocks for long lasting highly active SHG polymeric films

Journal	Data powered by TypesetDalton Transactions
Publisher	Data powered by TypesetRoyal Society of Chemistry (RSC)
ISSN	1477-9226
Open Access	Yes