Studies were carried out to develop a simple, rapid and accurate spectrophotometric method for the analysis of fifteen cephalosporins. The method depends on the charge-transfer complexation reaction between any of these drugs as an n-electron donor and p-chloranilic acid (p-CA) as a pi-acceptor to form a violet chromogen measured at 520 nm. Different variables affecting the reaction were studie...

A highly sensitive spectrofluorimetric method was developed for the first time, for the analysis of ten fluoroquinolones (FQs) antibacterials, namely amifloxacin (AMI), ciprofloxacin (CIP), difloxacin (DIF), enoxacin (ENO), enrofloxacin (ENR), lomefloxacin (LOM), levofloxacin (LEV), norfloxacin (NOR), ofloxacin (OFL) and pefloxacin (PEF) in their pharmaceutical dosage forms or in biological flu...

Synthetic polymers typically adopt a random-coil conformation in solution primarily driven by the tendency to maximize entropy. Generation of well-defined secondary structures in synthetic polymers, therefore, will need to include specific intrachain intersegment interactions that will provide adequate enthalpic contribution to overcome this entropic penalty associated with the formation of wel...

Article history: Received on: 07/09/2013 Revised on: 19/09/2013 Accepted on: 23/11/2013 Available online: 29/11/2013 This work presents two simple and direct spectrophotometric methods for determination of rabeprazole sodium (RB) through charge transfer complexation reactions. The first method is based on the reaction of the drug with p-chloranilic acid (p-CA) in acetonitrile to give a red colo...

We used tandem ion mobility spectrometry measurements to investigate how the photo-isomerization of a chromophore (a methylpyridinium derivative) is affected by the complexation with a crown ether. A dramatic blue-shift of the photo-isomerization spectrum was observed upon complexation, which could be well reproduced by ab initio calculations. Our results support that the observed changes in th...

Vibrational modes ascribed to the stretching of X-H bonds from donor monomers (HXdonor) in complexes presenting hydrogen bonds (HF···HF, HCl···HCl, HCN···HCN, HNC···HNC, HCN···HF, HF···HCl and H2O···HF) exhibit large (4 to 7 times) infrared intensity increments during complexation according to CCSD/cc-pVQZ-mod calculations. These intensity increases are explained by the charge-charge flux-dipol...