Isotope shifts and spin−spin coupling constants in the 13C and 17O NMR spectra of carbon monoxide and carbon dioxide

摘要: Oxygen isotope shifts on the 13C chemical and carbon 17O in monoxide dioxide are reported. Using models developed by Jameson, shielding derivatives with respect to bond lengths can be calculated using measured shifts. For monoxide, were [∂σ (13C)/∂r]e =−456±15 ppm/A (17O)/∂r]e =−1150±130 ppm/A. Although earlier coupled Hartree–Fock calculations give a much lower value for (17O)/∂r]e, recent ab initio agree very well our experimental results. Furthermore, observed 18O/16O iostope shift is similar values previously series of metal carbonyls. gives =−214±17 which excellent agreement obtained from variable temperature gas phase NMR study. In addition, scalar spin–spin coupling constants, 1J(13C,17O) 16.4±0.1 Hz carbo...