Some properties of subclass of multivalent functions associated with a generalized differential operator.

In this paper, the new subclass S b , λ , δ , p n ( α ) of a linear differential operator's N λ , δ , p n f ( ζ ) associated with multivalent analytical function has been introduced. Further, the coefficient inequalities, extreme points for the extremal function, sharpness of the growth and distortion bounds, partial sums, starlikeness, and convexity of the subclass is investigated.

Spectral and electrochemical study of host-guest inclusion complex between 2,4-dinitrophenol and ß-cyclodextrin.

The formation of host-guest inclusion complex of 2,4-dinitrophenol (2,4-DNP) with nano-hydrophobic cavity of ß-cyclodextrin (ß-CD) in solution phase was studied by UV-visible spectrophotometer and electrochemical method (cyclic voltammetry, CV). The prototropic behaviors of 2,4-DNP with and without ß-CD and the ground state acidity constant (pK(a)) of host-guest inclusion complex (2,4-DNP-ß-CD) were studied. The binding constant of inclusion complex at 303K was calculated using Benesi-Hildebrand plot and thermodynamic parameter (ΔG) was also calculated. The solid inclusion complex formation between ß-CD and 2,4-DNP was confirmed by (1)H NMR, FT-IR, XRD and SEM analysis. A schematic representation of this inclusion process is proposed by molecular docking studies using PatchDock server.

Study of inclusion complex of ß-cyclodextrin and diphenylamine: photophysical and electrochemical behaviors.

The photophysical, electrochemical and photoprototropic behaviors of diphenylamine (DPA) in aqueous ß-cyclodextrin (ß-CD) solution have been investigated using absorption spectroscopy and cyclic voltammetric techniques. Absorption of the neutral and cationic form of DPA is enhanced due to the formation of a 1:1 complex with ß-CD. The formation of this complex has been confirmed by Benesi-Hildebrand plot and docking studies by RasMol tool methods. The solid complex of ß-CD with DPA is investigated by FT-IR, XRD and AFM methods. The thermodynamic parameters (ΔG, ΔH and ΔS) of inclusion process are also determined. The pK(a) values of neutral-monocation equilibria have been determined with absorption (conjugate acid-base) titrations. A mechanism is proposed to explain the inclusion process.

Host-guest interaction of L-tyrosine with beta-cyclodextrin.

The inclusion complexes of beta-cyclodextrin (beta-CD) with L-tyrosine (L-TYN) were investigated by using spectrophotometers. The absorption and fluorescence enhancement occurs with beta-CD and L-TYN forms 1:1 inclusion complex. The unusual blue shift of hydroxyl ion in the beta-CD medium confirms OH groups present in the interior part of the beta-CD cavity and -COOH group present in the upper part of the beta-CD cavity. A mechanism is proposed to explain inclusion process. The inclusion interaction was examined and the thermodynamic parameters of inclusion process DeltaG, DeltaH and DeltaS were determined. The results indicated that the inclusion process was an exergonic and spontaneous process. Stable solid inclusion complexes were established and characterized by FT-IR, scanning electron microscope (SEM) methods.

Effects of solvent, pH and beta-cyclodextrin on the photophysical properties of 4-hydroxy-3,5-dimethoxybenzaldehyde: intramolecular charge transfer associated with hydrogen bonding effect.

The photophysical properties of 4-hydroxy-3,5-dimethoxybenzaldehyde (HDMB) in various solvents, pH and in aqueous beta-cyclodextrin (CD) have been investigated. In non-polar solvents, HDMB gives only one emission maxima; whereas, in polar solvents it shows a dual luminescence. The increase in Stokes shift with increase in polarity is much more for longer wavelength (LW) than for a shorter wavelength (SW) band. This behaviour indicates the formation of an intramolecular charge transfer (ICT) state through relaxation from the normal excited state. Especially in water, the ICT emission is further red shifted to 430 nm with the normal emission band at 330 nm and the relative fluorescence intensities between 330 nm and 430 nm emission bands are affected by the excitation wavelength. However, this excitation wavelength dependence is not large in aqueous beta-CD solutions. These results suggest that the ICT state in polar solvents/water is stabilized through exciplex formation by the hydrogen-bonding interaction between the carbonyl group and polar solvents/water. The ground and excited state pK(a) values for the neutral-monoanion equilibrium have been measured and discussed. HDMB forms a 1:1 inclusion complex with beta-CD. A mechanism is proposed to explain the inclusion process.

Dual fluorescence of diphenyl carbazide and benzanilide: effect of solvents and pH on electronic spectra.

The absorption and fluorescence spectra of benzanilide (BA) and diphenyl carbazide (DPC) in solvents of different polarities and pH have been analysed. The spectral characteristics of DPC and BA are compared with diphenyl amine molecule. In water and methanol, a dual fluorescence is observed for both DPC and BA molecules. The normal stokes shifted emission originates from a locally excited pi* electronic state and the large stokes shifted band is due to emission from a twisted intramolecular charge transfer (TICT) state. pH studies show that both monocations and monoanions are non-fluorescent. The excited state acidity constants determined by fluorimetric titration and Förster cycle methods, have been reported and discussed.

Spectral characteristics of ortho, meta and para dihydroxy benzenes in different solvents, pH and beta-cyclodextrin.

Spectral characteristics of ortho, meta and para dihydroxy benzenes (DHB's) have been studied in different solvents, pH and beta-cyclodextrin. Solvent study shows that: (i) the interaction of OH group with the aromatic ring is less than that of amino group both in the ground and excited states, (ii) in absorption, the charge transfer interaction of OH group in para position is larger than ortho and meta positions. pH studies reveals that DHB's are more acidic than phenol. The higher pK(a) value of oDHB (monoanion-dianion) indicates that the formed monoanion is more stabilized by intramolecular hydrogen bonding. DHB's forms a 1:1 inclusion complex with beta-CD. In beta-CD medium, absorption spectra of DHB's mono and dianions shows unusual blue shifts, whereas in the excited state, the spectral characteristics of DHB's follow the same trend in both aqueous and beta-CD medium.