Mohan B. Kalyankar

A core-substituted naphthalene diimide fluoride sensor.

The synthesis and characterization of a highly fluorescent core-substituted naphthalene diimide sensor (varphi = 0.34) bearing a bis-sulfonamide group is described. The compound shows a unique selectivity and reactivity for the fluoride ion over other anions in CHCl(3) by a two-stage deprotonation process leading to a colorimetric response. In DMSO solution, the sensor is shown to be highly selective for fluoride (K(a) approximately 10(6) M(-1)) over other anions with more pronounced changes in absorption characteristics.

The synthesis of novel core-substituted naphthalene diimides via Suzuki cross-coupling and their properties

This paper reports the efficient core-substitution of halogenated naphthalene diimides utilizing the Suzuki cross-coupling reaction to install various aryl substituents at the 2,6 positions. The UV-visible spectra of these compounds show a clear absorbance red shift and an enhanced fluorescence output, making them potential candidates for solar-cell dyes and electroactive elements for supramolecular materials.

One-Pot Synthesis of 2,4,5-Trisubstituted Imidazoles Using MoO3/SiO2, an Efficient and Recyclable Catalyst

Abstract A simple one-pot synthesis has been developed for the synthesis of 2,4,5-trisubstituted imidazoles using an efficient and recyclable MoO3/SiO2 solid acid catalyst by condensation of benzil or benzoin, benzaldehyde, and ammonium acetate in acetonitrile as a solvent. Using this solid catalyst, the reactions could be carried out under mild reaction conditions with very good yield of imidazoles, up to 95%. This catalyst could be recycled very easily, which makes this methodology environmentally benign.

Supramolecular self-assembly of protoporphyrin IX amphiphiles into worm-like and particular aggregates

A protoporphyrin IX amphiphile bearing hydrophobic–hydrophilic functional regions was synthesised by coupling protoporphyrin IX with methoxytriethylene glycol using (3-(dimethylamino)propyl)ethyl carbodiimide hydrochloride/1-hydroxybenzotriazole followed by a double-cross metathesis with 1-undecene using second-generation Grubbs catalyst. The self-assembling behaviour of the amphiphile in varying concentration of CHCl3/MeOH was investigated, with well-defined nanostructures described as worm-like fibrils and particular aggregates being formed in 1:1 and 1:9 v/v of MeOH/CHCl3, respectively.

Self-Assembly of Protoporphyrin IX-TEG Derivatives into Tunable Nanoscaled Spherical Structures

The results of a solvo-controlled self-assembly process involving a novel non-ionic protoporphyrin IX functionalized with triethylene glycol (Proto-NTEG) chains is discussed. In relatively non-polar aprotic solvents (cyclohexane/CHCl3), the protoporphyrin forms stable, uniformly-sized multilamellar micro-vesicles of approximately 65 nm diameter, while in more polar protic solvent mixes (CHCl3/MeOH), the same protoporphyrin forms micellar aggregates with dimensions of approximately 6 nm. The solvo-control operates based on the differing properties of glycol units in cyclohexane and methanol leading to inverse self-assembled structures.

One Pot Multi-Component Synthesis of N-Substituted Decahydroacridine- 1, 8-Diones Catalyzed by MoO3/SiO2 as an Efficient and Reusable Heterogeneous Catalyst

A simple, efficient and ecofriendly one pot synthesis protocol has been developed for the synthesis of N-substituted decahydroacridine-1,8-diones by using an efficient and recyclable solid acidic silica supported MoO3/SiO2 catalyst from a condensation of aldehyde, amine and cyclic 1,3-diketone in THF. The reaction using MoO3/SiO2 catalyst was carried out under mild condition with very high yields up to 92%. The present approach of this methodology offers several advantages such as shorter reaction times, good yields, low cost, environmentally benign, milder reaction conditions, easy recovery of catalyst and reusability.