Tin tetrachloride adducts with arylphosphoramidates: A multinuclear (~(31)P, ~(19)F, and ~(119)Sn) NMR characterization in solution

摘要

The synthesis of octahedral complexes [SnCl_4L_2] (L = R_2NP(O)(OCH_2CF_3)(O-p-tolyl): R_2N = Me_2N (1), Et_2N (2), CH_2(CH_2CH _2)_2N (3), and O(CH_2CH_2)_2N (4), or L = R_2NP(O)(OCH_2CF_3)(O-p-PhNO _2): R_2N = Me_2N (5), Et_2N (6), and O(CH_2CH_2)_2N (7) is described. The new adducts have been characterized by multinuclear (~(31)P, ~(19)F, ~(119)Sn) NMR, IR spectroscopy, and elemental analyses. The solution NMR data show the presence of a mixture of cis and trans isomers. The structure of the complexes in solution was further confirmed by ~(119)Sn NMR spectra, which display a triplet for each isomer, indicating an octahedrally coordinated tin center. The effects of the nature of R and Ar substituents on the donor ability of the P=O group in the ligands R_2NP(O)(OCH _2CF_3)(OAr) were investigated on the basis of ~(119)Sn NMR chemical shifts and used to classify these ligands according to their Lewis basicity.