摘要
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 have been refined by using a set of nitrogen and oxygen containing compounds to minimize the differences between 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 chemical shifts of three iron complexes(C_5H_5)Fe(CO)_2CN,(C_5H_4CHO)_2Fe_2,and(C_5H_4CH_2OH)_2Fe.The calculated ^(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 constants σ~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.The nitrogen and oxygen INDO parameters have been refined by using a set of nitrogen and oxygen containing compounds to minimize the differences between 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 chemical shifts of three iron complexes(C_5H_5)Fe(CO)_2CN,(C_5H_4CHO)_2Fe_2,and(C_5H_4CH_2OH)_2Fe.The calculated ^(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 constants σ~d(M)of ^(13)C,^(15)N and ^(17)O nuclei and the net charge ρ(M)of these atoms was noticed.
