Benzo-9-crown-3 ether: X-ray crystal structure, NMR studies in solution and the solid phase, and ab initio calculations of isotropic 13 C chemical shifts using LORG with a D95V basis set

• Published in: Canadian journal of chemistry 1993-12, Vol.71 (12), p.1983-1989
• Main Authors: Buchanan, G.W., Driega, A.B., Moghimi, A., Bensimon, C., Kirby, R.A., Bouman, T.D.
• Format: Article
• Language: English
• ISSN: 0008-4042; 1480-3291
• DOI: 10.1139/v93-247

Using the X-ray crystal geometry as input, the 13 C NMR chemical shifts of benzo-9-crown-3 ether have been calculated via ab initio methods using a localized orbital local origin (LORG) approach. Reasonable agreement is found between the calculated values for an isolated molecule in the gas phase and those obtained in the 13 C CPMAS NMR spectrum. Solid phase 13 C spectra of the C7,10-d 4 derivative confirm the existence of a 7.9 ppm shift difference between these sites in the solid, whereas in solution they are conformationally averaged to one resonance. The effects of C—H bond length variation on calculated 13 C shifts have been explored.