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In this paper,INDO perturbation theory has been extended to calculate the NMR chem-ical shifts of transition metal compounds.The nitrogen and oxygen INDO parameters havebeen refined by using a set of nitrogen and oxygen containing compounds to minimize the differencesbetween calculated and experimental ~(13)C,~(15)N,and ~(17)O shielding constants.These refined parameters,together with optimally selected iron INDO parameters,were used to evaluate the ~(13)C chemicalshifts of three iron complexes(C_5H_5)Fe(CO)_2CN,(C_5H_4CHO)_2Fe_2,and(C_5H_4CH_2OH)_2Fe.Thecalculated ~(13)C,~(15)N and ~(17)O shielding constants were fairly in agreement with experimental results.In addition,a good linear relationship between the calculated diamagnetic shielding constantsσ~d(M)of ~(13)C,~(15)N and ~(17)O nuclei and the net charge ρ(M)of these atoms was noticed.
In this paper, INDO perturbation theory has been extended to calculate the NMR chem-ical shifts of transition metal compounds. Nitrogen and oxygen INDO parameters havebeen refined by using a set of nitrogen and oxygen containing compounds to minimize the differencesbetween calculated and experimental ~ ( 13) C, ~ (15) N, and ~ (17) O shielding constants. These refined parameters, together with optimally selected iron INDO parameters, were used to evaluate the ~ (13) C chemicalshifts of three iron complexes (C_5H_5) (CO) _2CN, (C_5H_4CHO) _2Fe_2, and (C_5H_4CH_2OH) _2Fe.Thecalculated ~ (13) C, ~ (15) N and ~ (17) O shielding constants were fairly in agreement with the experimental results.In addition, relationship between the calculated diamagnetic shielding constants σ ~ d (M) of ~ (13) C, ~ (15) N and ~ (17) O nuclei and the net charge ρ (M) of these atoms was noticed.