ab initioDFT calculations 13C, 1H NMR chemical shifts and bond length in synthesized spirooxindol

Pure spirooxindol was synthesized and studied by both the experimental and calculational methods of NMR and Xray spectroscopy. Theoretical methods of substantial quality can be used to calculate NMR data using the gauge including atomic orbital (GIAO) method, yielding data comparable with those of the experiment. ab initio and DFT calculations of 13Cvand 1H NMR chemical shifts of the Novel Spirooxindol Compound were reported. The structure of this molecule at first wasvoptimized with the Gaussian 03 program. After the optimization, 13C and 1H chemical shifts were calculated with GIAOvmethod, using corresponding TMS shielding calculated at the same theoretical levels as the reference. Calculations have beenvperformed with using three different basis sets: 6-31G, 6-31G(d,p) and 6-31+G(d,p) at HF and DFT levels of theories. Thevresults, especially for 13C chemical shifts are in agreement with the experimental values of NMR. In this work the bond lengthsvof the Spirooxindol was calculated and the results compared with those of the experimental data obtained by X-Rayvcrystallography. All the computations were done using an IBM x225 Xeon computer that has 2048 MB ram.v