DFT study of molecular structures and 13C NMR parameters of two fluorinated biphenyls and their η6-tricarbonylchromium complexes

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• Conformations of fluorobiphenyls and their Cr(CO)3 complexes were studied by DFT.B3LYP-6-311++G(2d,p) method reproduced 13C NMR chemical shifts of those objects.BHandH-6-311++G(2d,p) method provided proper values of J(13C, 19F).

The molecular structures of 2,2′-difluoro-6,6′-dimethylbiphenyl, 4,5-difluoro-9,10-dihydrophenanthrene and of their η6-tricarbonylchromium complexes have been discussed in the light of the results of molecular energy calculations. Also the isotropic magnetic shielding constants and carbon–fluorine spin–spin coupling constants for these objects have been calculated and compared with the experimental values of 13C NMR chemical shifts and J constants. The calculational methods used were: DFT/BHandH/6-311++G(2d,p) and/or DFT/B3LYP/6-311++G(2d,p). It has been confirmed that experimental 13C NMR chemical shifts for η6-arene tricarbonylchromium complexes can be satisfactorily predicted using both methods, although the method exploiting BHandH functional is not able to reproduce the 13C NMR chemical shifts of Cr(CO)3 carbon atoms. On the other hand, this method provides the J(13C, 19F) values which are close to the experimental ones.