Synthesis and crystal structure of the mixed valent complex [Sn2I3(NPPh3)(3)]

The mixed valent phosphoraneiminato complex [Sn2I3(NPPh3)(3)] (1) was prepa red by the reaction of the tin(II) complex [SnI(NPPh3)](2) with sodium in t etrahydrofuran. 1 crystallizes with two formula units of THF to form yellow moisture sensitive single crystals, which were characterized by a crystal structure determination. 1.2 THF: Space group P2(1)/c, Z = 4, lattice dimensions at -80 degrees C: a =1964.5(2), b=1766.0(2), c=2058.6(2)pm; beta= 118.33(1)degrees, R=0.052. 1 forms dimeric molecules in which the tin atoms are linked by two nitrogen a toms of two (NPPh3-) groups to form a planar Sn2N2 four-membered ring. The Sn-IV atom is additionally coordinated by a terminal iodine atom and by a t erminal (NPPh3-) group, whereas the Sn-II atom is additionally coordinated by two iodine atoms forming a psi trigonal-bipyramidal surrounding.