Publications by authors named "Emandi Ganapathi"

Tetraphenylethylene (TPE) and its derivatives exhibit excellent aggregation-induced emission (AIE) properties. The TPE unit is easily accessible, and many functional groups can be introduced in a facile manner to yield effective luminescent materials in both solution and the solid-state. It is because of this, several TPE-based compounds have been developed and applied in many areas, such as OLEDs and chemical sensors.

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Bench-stable meso-substituted di(-benzi)homoporphyrins were synthesized through acid-catalyzed condensation of dipyrrole derivatives with aryl aldehydes. The insertion of a 1,1,2,2-tetraphenylethene (TPE) or but-2-ene-2,3-diyldibenzene unit in the porphyrin framework results in the formation of dibenzihomoporphyrins, merging the features of hydrocarbons and porphyrins. Single crystal X-ray analyses established the non-planar structure of these molecules, with the phenylene rings out of the mean plane, as defined by the dipyrromethene moiety and the two meso-carbon atoms.

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The first conceptualised class of dual-binding guanine quadruplex binders has been designed, synthesised and biophysically studied. These compounds combine diaromatic guanidinium systems and neutral tetra-phenylporphyrins (classical binding moiety for guanine quadruplexes) by means of a semi-rigid linker. An extensive screening of a variety of guanine quadruplex structures and double stranded DNA via UV-vis, FRET and CD experiments revealed the preference of the conjugates towards guanine quadruplexes.

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Efficient photon-harvesting materials require easy-to-deposit materials exhibiting good absorption and excited-state transport properties. We demonstrate an organic thin-film material system, a palladium-porphyrin-based surface-anchored metal-organic framework (SURMOF) thin film that meets these requirements. Systematic investigations using transient absorption spectroscopy confirm that triplets are very mobile within single crystalline domains; a detailed analysis reveals a triplet transfer rate on the order of 10 s.

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Article Synopsis
  • Crystalline SURMOF thin films made from porphyrin-based organic linkers are being explored for photon upconversion and photovoltaic applications.
  • These materials show potential but raise concerns about their stability when exposed to light, necessitating further investigation.
  • Research using various spectroscopy techniques reveals that prolonged illumination alters the material's photoresponse due to stable photodecomposition products, leading to the formation of short-lived radical pairs through electron transfer processes.
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The title compound, CHNOS, was obtained in an improved yield compared to previous literature methods. The mol-ecule is essentially planar with a maximum deviation of 0.085 Å from the mean plane through all non-H atoms.

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We report 4-(2-(5-(tert-butyl)-3-formyl-2-hydroxyphenyl)-1H-phenanthro[9,10-d]imidazol-1-yl)benzoic acid 1 and 4-(2-(5-(tert-butyl)-3-formyl-2-hydroxyphenyl)-4,5-diphenyl-1H-imidazol-1-yl)benzoic acid 2 as reversible luminescent sensors for the detection of cyanide and mercury ions. These imidazole derivatives were characterized using spectroscopic techniques and single crystal X-ray crystallography. The compounds showed sensing exclusively towards CN- ions, which resulted in the quenching of fluorescence and a decreased singlet state life time.

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3,5-Diformyl-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (3,5-diformyl-BODIPY) can be used as an efficient biofunctional cross-linker to generate a new class of chitosan-based hydrogels with fluorescence resonance energy transfer (FRET) dynamics and good solubility in water. The hydrogel was fully characterized by FT-IR, UV-vis, fluorescence, FE-SEM, AFM, rheology and picosecond time-resolved spectroscopic techniques. The self-healing ability was demonstrated by rheological recovery and macroscopic and microscopic observations.

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Two unprecedented mixed B(III) /P(V) complexes of meso-triaryl 25-oxasmaragdyrins were synthesized in appreciable yields under mild reaction conditions. These unusual 25-oxasmaragdyrin complexes containing one or two seven-membered heterocyclic rings comprised of five different atoms (B, C, N, O, and P) were prepared by reacting B(OH)(Ph)-smaragdyrin and B(OH)2 -smaragdyrin complexes, respectively, with POCl3 in toluene at reflux temperature. The products were characterized by HRMS and 1D- and 2D-NMR spectroscopy.

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meso-Pyrrolyl boron dipyrromethene (BODIPY) was prepared under simple reaction conditions by using commercially available chemicals. Prior to this work, the BODIPY compound was prepared in multiple steps by using precursors which were not readily available. The X-ray structure of BODIPY revealed that the meso-pyrrole ring is tilted towards the BF2-dipyrrin moiety with a dihedral angle of 33.

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Expanded dithiacalixphyrins with the N(2)S(2) core containing two sp(3) and three sp(2) meso-carbons have been prepared by condensation of one equivalent of butene-2,3-diyl-bisthiophene-2,5-diyl-bis(p-methoxyphenylmethanol) with one equivalent of 5,5'-dialkyldipyrromethane under mild acid catalyzed conditions in decent yields. The expanded dithiacalixphyrins were characterized by HR-MS, 1D and 2D NMR techniques and the structure of one of the expanded dithiacalixphyrin macrocycles was solved by X-ray crystallography. The crystal structure analysis indicated that the macrocycle is highly distorted and attains a boat shaped structure.

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