Structural and vibrational study of the Ci(1) conformation of 18-crown-6.
Optimized geometry, vibrational frequencies and IR absorption intensities were calculated for the Ci(1) conformation of 18c6. Optimized geometry was compared with the experimental geometry and that of the Ci(2) conformation of 18c6. The Ci(1) conformation is more planer than the Ci(2) conformation of 18c6, which provides an explanation that free 18c6 in the crystal phase has a Ci(1) conformation. Vibrational frequencies were scaled using an unvaried one-scale-factor scaling of 0.928. Calculated vibrational frequencies were compared with the experimental vibrational frequencies. The root-mean-square deviation of the difference between the calculated and experimental frequencies was only 15 cm(-1). This excellent agreement between the calculated and experimental frequencies is an indication of the proper assignment of the fundamental vibrational frequencies of the Ci(1) conformation of 18c6.
Host Guest Complex Chemistry I
The solvent extraction of metal ions by crown compounds.- Crown compounds as alkali and alkaline earth metal ion selective chromogenic reagents.- Photocontrol of ion extraction and ion transport by photofunctional crown ethers.- Macroheterocyclic ligands on polymers.- Synthesis and metal complexes of aza-macrocycles with pendant arms having additional ligating groups.- Bridged, capped and fenced porphyrins.
Raman temperature study of 12-crown-4 using Fourier deconvolution of CH stretching spectra
Abstract The Raman CH Stretching spectra of 12C4 in water solution, for temperatures from 5 to 80 °C, are studied. For the first time, Fourier deconvolution technique is applied to resolve the overlapped components in the corresponding isotropic and anisotropic spectra. The results are treated by means of a model. explaining the variety of resolved components with a splitting of the unperturbed CH stretching vibration. owing to intramolecular interactions. The temperature behaviour of the coupling constants of these interactions is discussed.