FPT-CNDO/INDO化学屏蔽常数计算方法及其在Mo和Co化合物中的应用

Semi -empirical molecular orbital methods within the framework of the finite perturbation theory , the FPT-CNDO/INDO methods , which consist of the FPT-CNDO/2 and FPT-INDO methods, are set up for the study of chemical shielding in transition metal compounds, and a corresponding computational program is developed on VAX 11/785 computer to establish a theoretical study of the transition metal chemical shielding by quantum chemistry methods. Application of the methods has been carried out in the calculation of 95Mo chemical shielding constants of mononuclear precursors MoOnS4-n]2-(n=0-4). With the standard CNDO/INDO parameters a linear regression was obtained between the calculated results and the corresponding experimental data:δcal=(0.8345 δexp-43.83)ppm, with a correlation coefficient of 0.999. Investigation on the calculated electronic configuration confirms that in MoOnS4_n]2- (n=0-4)95Mo chemical shifts are dominated by the d-orbital paramagnetic contribution arising from the d-d transition. Appl

THE FPT-CNDO/INDO METHOD FOR CHEMICAL SHIELDING CONSTANT OF TRANSITION METAL ELEMENTS AND ITS APPLICATIONS IN Mo AND Co COMPOUNDS