New versatile versatile phosphorus-containing ligands—asymmetric (XPR_2)(YPR'_2)NH (X, Y = O, S; R, R' = Ph, OEt) and their potassium salts: the crystal and molecular structures of (SPPh_2)[OP(OEt)_2]NH, K[(SPPh_2){OP(OEt)_2}N] centre dot H_2O and (

摘要

(XPPh_2)[YP(OEt)_2]NH (X, Y = O, S) were prepared as white crystalline solids using a new method of synthesis, i.e. the reaction between Li[HN(X)PR_2] and R'_2P(Y)Cl in a benzene-hexane mixture. Both free acids and their K salts were characterised by IR and multinuclear (~1H, ~(13)C, ~(31)P) NMR spectroscopy. The monothio acid, (SPPh_2)[OP(OEt)_2]NH (1), crystallises in the monoclinic space group P2_1. The molecule of 1 exhibits an anti conformation of the chalcogen atoms in the SPNPO system and the crystal contains dimeric pairs formed through N-H...O(=P) hydrogen bonds. The potassium salt crystallises as a monohydrate, K[(SPPh_2){OP(OEt)_2}] centre dot H_2O (2), in the triclinic space group P1-bar. There are two independent molecules in the cell unit. Four or them are associated to form a tetranuclear architecture through O-water and terminal O-phosphorus bridging atoms, and interactions between K(1) atoms and aromatic carbons of a phenyl group attached to phosphorus. Moreover, these tetranuclear units are linked together into a quite complicated polymeric structure through terminal O-phosphorus bridging atoms and K...O-ethoxy interactions. The potassium ions of the two independent molecules exhibit a different coordination core. K(1) has the coordination number 9: a S,O-chelating phosphorus ligand, an O,O(Et)-coordinated neighbouring phosphorus ligand, two oxygens from water molecules and three carbons of a phenyl group. K(2) has the coordination number 6: a S,O-chelating phosphorus ligand, an O,O(Et)-coordinated neighbouring phosphorus ligand, and two oxygens from water molecules. The dioxo acid crystallises as (OPPh_2)[OP(OEt)_2]NH centre dot 1/2HCl centre dot 1/4H_2O (3), in the tetragonal space group P4_12_12. The molecule of 3 exhibits a syn conformation of the chalcogen atoms in the SPNPO system and the crystal contains chain polymers built through N-H...Cl...H-N and P=O...H-O-H...O=P hydrogen bonds.