Specord s600 spectrometer

All chemicals used in the present study were procured from Sigma-Aldrich, Alfa Aesar or Spectrochem and used as received. All solvents were purchased from SD Fine, India, were of HPLC grade and used without further distillation. Melting points were measured on a Stuart SMP3 melting point apparatus in open capillaries. Infrared spectra were recorded on a Bruker alpha FTIR spectrometer. UV–vis spectroscopy was performed with an Analytik Jena Specord S600 spectrometer in a standard 3.0 mL quartz cell with 1 cm path length. The ¹H NMR spectra were recorded on Bruker Ascend (400 MHz) instrument using TMS as internal reference and DMSO-d₆ as solvent. Resonance multiplicities are described as s (singlet), d (doublet), t (triplet) and m (multiplet). Mass spectra were recorded using a DART-MS, JMS-T100LC, Accu TOF Mass Spectrometer. Elemental analysis was performed with an ELEMENTOR Micro analysis system, varioMICRO CUBE CHNS.
Synthesis of receptors R1 and R2: Receptors R1 and R2 were synthesized through a Schiff base condensation reaction of the corresponding aromatic aldehyde and amine (Scheme 5).