Chennan Ramalingan

Novel metal-free organic dyes possessing fused heterocyclic structural motifs for efficient molecular photovoltaics

Reported herein are six novel metal free organic dyes such as PCA1-PCA3 and PCTA1-PCTA3 featuring fused heterocyclic structural motifs such as phenothiazine and alkylcarbazole. Photophysical/electrochemical properties and nanocrystalline TiO2 based dye-sensitized solar cell performance of the same have been investigated. Electronic distribution within the molecules has been determined through a computational approach. The overall power conversion efficiencies of the devices with the utilization of dyes PCA1-PCA3 and PCTA1-PCTA3 as sensitizers ranges between 4.67 and 8.08%. The novel dyes possessing cyanoacrylic acid as electron acceptor, PCA1-PCA3, exhibit higher power conversion efficiency, short-circuit current, open-circuit voltage, and electron lifetime those with thioxothiazolidinylacetic acid, PCTA1-PCTA3, as the same. Of the devices fabricated by employing the new metal-free organic sensitizers, that with the dye PCA2 exerted a power conversion efficiency (PCE, η) of 8.08% with a short circuit current density (JSC) of 16.45 mA cm-2, an open circuit voltage (VOC) of 735 mV and a fill factor (ff) of 0.68; this PCE is the highest amongst the devices fabricated.

A Mechanochemical Approach for the Construction of Carbon–Carbon Double Bonds: Efficient Syntheses of Aryl/Heteroaryl/Aliphatic Acrylates and Nitriles

An efficient method for the construction of carbon–carbon double bond has been developed from aromatic aldehydes and compounds with active methylene moieties in the presence of catalytic amount of solid sodium ethoxide via mechanochemical approach. This capable process provides a diverse range of homoaryl/heteroaryl/aliphatic acrylates and nitriles in good to excellent yields at short reaction period.Graphical Abstract

(4E)-N-[(2-Chloro-phen-yl)meth-oxy]-1,3-dimethyl-2,6-diphenyl-piperidin-4-imine.

In the title compound, C26H27BrN2O, the piperidine ring has a chair conformation and all ring substituents occupy equatorial positions, apart from the double-bonded N atom, which occupies a bisectional position. The dihedral angle formed between the phenyl rings is 61.18 (19)°, and the phenyl rings form dihedral angles of 49.78 (19) and 69.2 (18)° with the bromobenzene ring. The latter is coplanar with the methoxy(methylidene)amine fragment [N—O—C—C torsion angle = −171.7 (2)°]. Linear supramolecular chains, approximately along [112], sustained by C—H⋯π interactions, feature in the crystal packing.

Chemoselective synthesis and spectral studies of N-thiocyanatoacetyl derivatives of 3-alkyl-2,6-diarylpiperidin-4-ones

GRAPHICAL ABSTRACT ABSTRACT A series of N–thiocyanatoacetyl derivatives of 3–alkyl–2,6–diarylpiperidin–4–ones has been synthesized by the reaction between the N–chloroacetyl derivatives of the respective piperidin–4–ones and the ambident thiocyanate nucleophile. The synthesized compounds have been characterized through FT–IR, 1H, 13C, 1H–1H COSY, 1H–13C COSY and NOESY spectra. The spectral data reveal the conformational priority of the six-membered heterocyclic ring.

N-(2-Fluoro­benz­yloxy)-1,3,5-trimethyl-2,6-diphenyl­piperidin-4-imine

In the title compound, C27H29FN2O, the piperidine ring has a twisted boat conformation and all ring substituents occupy equatorial positions. The dihedral angle formed between the phenyl rings is 66.71 (12)°, and the phenyl rings form dihedral angles of 46.60 (13) and 43.75 (13)° with the fluorobenzene ring, which occupies a position coplanar to the methoxy(methylidene)amine residue [N—O—C—C torsion angle = −179.5 (2)°]. In the crystal, a complex network of C—H⋯π interactions connects the molecules into a three-dimensional architecture.

1-(2-Chloro­benz­yl)-3-methyl-2,6-diphenyl­piperidine

In the title compound, C25H26ClN, the piperidine ring has a chair conformation with all ring substituents in equatorial positions. The dihedral angle formed between the chlorobenzene ring and the flanking phenyl rings are 74.91 (18) and 47.86 (17)°. The chloro substituent is anti to the piperidine N atom. In the crystal, centrosymmetrically related molecules aggregate via π–π interactions occurring between chlorobenzene rings [centroid–centroid distance = 3.778 (2) Å] and these are linked into linear supramolecular chains along the a axis by C—H⋯π interactions occurring between the phenyl rings.