Indian Association for the Cultivation of Science

About: Indian Association for the Cultivation of Science is a education organization based out in Kolkata, India. It is known for research contribution in the topics: Excited state & Catalysis. The organization has 3867 authors who have published 10457 publications receiving 220098 citations.

Intercalation of Perylenediimide Dye into LDH Clays: Enhancement of Photostability

Abstract: Intercalation of perylenediimide dye into a host layer of layered double hydroxide (LDH) by the anion-exchange method is studied. N,N′-Bis(4-benzosulfonic acid)perylene-3,4,9,10-tetracarboxylbisimide disodium salt (PRSA) has been synthesized and intercalated into the perchlorate form of ZnAl-, CoAl-, and NiAl−LDH. LDH composite with well-defined morphology has been prepared. XRPD and FT-IR investigation show successful intercalation of PRSA, and the interlayer distances are 32.5 A for ZnAl−LDH−PRSA, 30.0 A for CoAl−LDH−PRSA, and 31.2 A for NiAl−LDH−PRSA. These values support the presence of monolayer arrangement of intercalated PRSA molecules in the composite and also indicate vertical orientation of PRSA molecules with the basal plane of LDH. Photophysical properties of these intercalated composites have been measured with UV−vis spectroscopy, photoluminescence spectroscopy, and confocal laser scanning microscopy. The results indicate that the PRSA molecules are stacked in J-type aggregation in the inter...

Solvation dynamics of 4-aminophthalimide in water-in-oil microemulsion of triton X-100 in mixed solvents

Abstract: Solvation dynamics of 4-aminophthalimide (4-AP) in water-in-oil microemulsion of Triton X-100 (TX) in mixed solvents containing 30% benzene and 70% n-hexane is studied using picosecond time-resolved Stokes shift. The steady-state emission spectrum of 4-AP in this microemulsion is very different from that in TX reverse micelle or in water. This indicates that in this microemulsion the 4-AP molecule stays in the water pool and the micropolarity of the water pool is very much different from that of ordinary bulk water. In TX microemulsions 4-AP exhibits wavelength-dependent fluorescence decays and a growth in the nanosecond time scale at long wavelengths. The solvation dynamics of 4-AP in TX microemulsion is bimodal with a short component of 0.74 ns and a very long component of 29.73 ns. This is similar to the solvation dynamics of coumarin 480 in the large water pools of sodium dioctyl sulfosuccinate (AOT)/n-heptane/water microemulsions.

Stereoselective Synthesis of Polysubstituted Tetrahydrofurans by Radical Cyclization of Epoxides Using a Transition-Metal Radical Source. Application to the Total Synthesis of (±)-Methylenolactocin and (±)-Protolichesterinic Acid

Abstract: Radical cyclization reactions of substituted α-(prop-2-ynyloxy) epoxides using bis(cyclopentadienyl)titanium(III) chloride as the radical source resulted in polysubstituted tetrahydrofurans. Titanium(III) species were prepared in situ from commercially available titanocene dichloride and zinc dust in tetrahydrofuran. Upon radical cyclization, 2-aryl epoxides 3a−e afforded only trans products 4a−e whereas the 2-alkyl epoxides 3f−h formed a mixture of isomeric products 4f−h in a ratio of 5:1. Some of the aryl tetrahydrofuran derivatives have already been used for the synthesis of bioactive furofuran lignans. 2-Pentyl-3-(hydroxymethyl)-4-methylenetetrahydrofuran (4f) and 2-tridecyl-3-(hydroxymethyl)-4-methylenetetrahydrofuran (4g) have been transformed to two antitumor antibiotics (±)-methylenolactocin (1f) and (±)-protolichesterinic acid (1g), respectively, in good overall yield.

Sulfonic Acid-Doped Thermoreversible Polyaniline Gels: Morphological, Structural, and Thermodynamical Investigations

Abstract: Polyaniline (PANI) forms thermoreversible gels in four different sulfonic acids, e.g., dinonylnaphthalene sulfonic acid (DNNSA), dinonylnapthalene disulfonic acid (DNNDSA), ±camphor-10-sulfonic aci...

Isolation and Structure of the First Azo Anion Radical Complexes of Ruthenium.

Abstract: The anaerobic reaction of 1 (X = H, Cl) with 2 in heptane affords the green paramagnetic (S = 1/2) and EPR-active (g = 2.00) title complexes 3a (X = H) and 3b (X = Cl), which furnish the corresponding nonradical diamagnetic salts 3a+ PF6- and 3b+ PF6- upon oxidation in solution. In contrast, the reaction of 2 with N-(p-tolyl)pyridine-2-aldimine (pal) affords [Ru(pal)(H)(Cl)(CO)(PPh3)]. The X-ray structures of 3a and 3b+ have been determined.