CRYSTAL AND MOLECULAR-STRUCTURES OF (OPPH2)(SPPH2)NH AND ITS SODIUM-SALT [NA((OPPH2)(SPPH2)N)CENTER-DOT-2THF](2)

A new method of synthesis, i.e. the reaction between Li[HN(S)PPh2] and Ph2P(O)Cl in a diethyl ether/n-hexane mixture, was used for the prepa ration of tetraphenylmonothioimidodiphosphinic acid. Its sodium salt w as obtained by reacting the free acid with NaH in THF. The solid state structures of both compounds were determined by X-ray crystallography . (OPPh2)(SPPh2)NH (1) contains two independent molecules in the unit cell. Both molecules exhibit an anti conformation of the chalcogen ato ms in the OPNPS system. In the crystal the molecules of 1 are associat ed into polymeric chains through hydrogen bonds involving only the oxy gen atoms of each molecule [av. (N-)H ... O 2.09 Angstrom]. The sodium salt of this acid can be considered to be built up of centrosymmetric dimers [Na{(OPPh2)(SPPh2)N}. 2THF](2)(2). The O atom of the ligand un it acts as a bridging atom between the two Na atoms of the dimer [Na(1 )-O(1)2.245(9), Na(1)-O(1)' 2.396(9) Angstrom]. In addition Na(1) is a lso coordinated by the S(1)' atom [Na(1)-S(1)'2.975(6) Angstrom] and t he oxygen atoms of two THF molecules [Na(1)-O(2) 2.37(1), Na(1)-O(3) 2 .35(1) Angstrom]. This results in a trigonal bipyramidal geometry arou nd sodium atoms [O(1)' and O (3) in axial positions for Na(1), O(3)-Na (1)-O(1)' 171.5(4)degrees], and a tricyclic system with a-central plan ar four-membered Na2O2 ring. (C) 1997 Elsevier Science Ltd.