Inclusion complexation of phenoxyaliphatic acid derivatives of 3,3'-bis(indolyl)methanes with ß-cyclodextrin.

The inclusion complexation behavior of phenoxyaliphatic acid derivatives of 3,3'-bis(indolyl)methane (BIMs 1-5) with ß-cyclodextrin (ß-CD) were investigated in both solution and solid state by means of UV-Visible, fluorescence spectroscopy, FT-IR and (1)H NMR techniques. The nature of the host-guest inclusion complex between BIMs and ß-CD has been elucidated. The experimental results confirmed the existence of 1:1 inclusion complex of BIMs with ß-CD. The binding constants describing the extent of formation of the complexes have been determined using Benesi-Hildebrand plots using UV-Vis and fluorescence spectroscopy. BIMs exhibited an affinity for ß-CD. The spectral studies suggested the phenyl ring along with alkyl substitutions of BIMs is present inside of ß-CD cavity.

In situ Bronsted-Lowry acid catalyzed syntheses, characterization, single crystal XRD, electronic spectral-, DPPH radical scavenging-, and DNA protection studies of aryl-3,3'-bis(indolyl)methanes.

A series of novel aryl-3,3'-bis(indolyl)methanes (BIMs) were synthesized using indole and formylphenoxyaliphatic acid(s) in water in the absence of any catalyst. The formylphenoxyaliphatic acid behaves as an in situ Bronsted-Lowry acid catalyst in water. UV-Visible and fluorescence spectra of the compounds were recorded in selected solvents. The gas phase geometry optimization of the compounds were achieved using DFT calculations at B3LYP/3-21G((*)) level of theory. The electronic properties, such as HOMO-LUMO energies were calculated using the above method based on the optimized structure. Compounds have better DPPH radical scavenging activity and reduction of oxidative damage of DNA.

Excimer formation in inclusion complexes of ß-cyclodextrin with salbutamol, sotalol and atenolol: spectral and molecular modeling studies.

The inclusion complexation behavior of salbutamol, sotalol and atenolol drugs with ß-cyclodextrin (ß-CD) were investigated by UV-visible, fluorometry, time resolved fluorescence, FT-IR, (1)H NMR, SEM and PM3 methods. The above drugs gave a single emission maximum in water where as dual emission in ß-CD. In ß-CD solutions the shorter wavelength fluorescence intensity was regularly decreased and longer wavelength fluorescence intensity increased. Addition of ß-CD to aqueous solutions of drugs resulted into excimer emission. The excimer emission is concluded to be due to a 1:2 inclusion complex between ß-CD and drug. Nanosecond time-resolved studies indicated that all drugs exhibited biexponential decay in solvents and triexponential decay in CD. Investigations of thermodynamic and electronic properties confirmed the stability of the inclusion complex.

Azo-hydrazo tautomerism and inclusion complexation of 1-phenylazo-2-naphthols with various solvents and beta-cyclodextrin.

Spectral characteristics of sudan I (SDI), sudan II (SDII) and mordant violet-5 (MV5) have been studied in various solvents and beta-cyclodextrin (beta-CD). The inclusion complex of the above molecules with beta-CD was analyzed by UV-visible, fluorometry, and DFT methods. The solvent study shows that azo-hydrazo tautomer is present in these molecules. The increase in the fluorescence intensity and a large bathochromic shift in the S(1) state indicate these molecules forms 1:1 inclusion complex with beta-CD.

Unusual spectral shifts on fast violet-B and benzanilide: Effect of solvents, pH and beta-cyclodextin.

The absorption and fluorescence spectra of fast violet-B (FVB) and benzanilide (BA) have been analysed in different solvents, pH and beta-cyclodextrin. The inclusion complex of FVB with beta-CD is investigated by UV-visible, fluorimetry, AM 1, FTIR and SEM. The absorption maximum of FVB (anilino substitution) is red shifted than that of BA, but the benzoyl substitution hardly changed the ground state structure of BA. Compared to BA, the emission maxima of FVB largely blue shifted in cyclohexane and aprotic solvents, but red shifted in protic solvents and the longer wavelength maxima in FVB is due to the intramolecular charge transfer (TICT). In BA, the normal emission originates from a locally excited state and the longer wavelength band due to intramolecular proton transfer in non-polar/aprotic solvents and in protic solvents it is due to TICT state. beta-CD studies reveal that, FVB forms 1:2 complex from 1:1 complex and BA forms 1:2 complex with beta-CD.