RESUMEN
In N,N'-di-tert-butyl-N'',N''-dimethylphosphoric triamide, C(10)H(26)N(3)OP, (I), and N,N',N'',N'''-tetra-tert-butyl[oxybis(phosphonic diamide), [corrected] C(16)H(40)N(4)O(3)P(2), (II), the extended structures are mediated by P(O)...(H-N)(2) interactions. The asymmetric unit of (I) consists of six independent molecules which aggregate through P(O)...(H-N)(2) hydrogen bonds, giving R(2)(1)(6) loops and forming two independent chains parallel to the a axis. Of the 12 independent tert-butyl groups, five are disordered over two different positions with occupancies ranging from 1/6 to 5/6. In the structure of (II), the asymmetric unit contains one molecule. P(O)...(H-N)(2) hydrogen bonds give S(6) and R(2)(2)(8) rings, and the molecules form extended chains parallel to the c axis. The structures of (I) and (II), along with similar structures having (N)P(O)(NH)(2) and (NH)(2)P(O)(O)P(O)(NH)(2) skeletons extracted from the Cambridge Structural Database, are used to compare hydrogen-bond patterns in these families of phosphoramidates. The strengths of P(O)[...H-N](x) (x = 1, 2 or 3) hydrogen bonds are also analysed, using these compounds and previously reported structures with (N)(2)P(O)(NH) and P(O)(NH)(3) fragments.
RESUMEN
Transport of Ag(i), Cd(ii), Co(ii), Cu(ii), Ni(ii), Pb(ii) and Zn(ii) cations across a bulk liquid membrane (BLM) containing N,N'-dibenzyl-N''-(2,2,2-trifluoroacetyl)-phosphoric triamide (PTC) as a new carrier is studied by atomic absorption spectrometry. The results show selective and efficient transport of the copper(ii) cation from aqueous solution in the presence of the other cations. Various factors are optimized in order to obtain maximum transport efficiency. The PTC ligand is characterized by single crystal X-ray diffraction analysis, IR, NMR (19F, 31P, 1H, 13C) and mass spectroscopy. The complex formation reaction between copper(ii) and PTC is studied by a conductometric method, which shows the 1 : 1 stoichiometry for ligand and copper(ii).