POLYOXOMETALATE DERIVATIVES WITH MULTIPLE ORGANIC GROUPS .1. SYNTHESIS AND STRUCTURES OF TRIS(ORGANOTIN) BETA-KEGGIN AND ALPHA-DAWSON TUNGSTOPHOSPHATES

Tris(organotin)-substituted Keggin and Dawson tungstophosphates, [(PhS nOH)(3)(PW9O34)2](12-)(1), [(BUsnOH)(3)(PW9O34)(2)](12-)(2), [(PhSn)(3 )P2W15O59](9-)(3), and [(BuSn)(3)P2W15O59](9-)(4), have been prepared by reaction of the organotin trichlorides with Na8H[A-PW9O34].chi H2O and Na-12-[alpha-P2W15O56].24H(2)O, respectively. The products were ch aracterized by elemental analysis, infrared spectroscopy, multinuclear NMR, and X-ray crystallography. Crystals of K11H-[(PhSnOH)(3)(PW9O34) (2)]. 16H(2)O are tetragonal, space group I4/amd, with lattice constan ts a =b=35.522(5)Angstrom, c=33.243(7)Angstrom V=41946(12)Angstrom(3). R=0.0863 for 350 variable parameters and 5664 reflections with I > 2 sigma(I). The anion has nominal D-3h symmetry and contains three PhSnO H groups sandwiched between A,beta-PW9O349- anions. It is an isomer of the complex reported by Knoth (Organometallics 1985, 4, 62-68), which is presumed to contain A,alpha-PW9O349-. Crystals of K5H4[PhSn)(3)P2W 15O59].6H(2)O are also tetragonal, space group I4/ m, with lattice con stants a=b=30.096(4)Angstrom, c=22.196(5) Angstrom, V=20105(6) Angstro m(3). R=0.0936 for 290 variable parameters and 5761 reflections with I > 2 sigma(I). The anion has the anticipated C-3v Dawson structure wit h three cap {WO}(4+) replaced by {SnPh}(3+). Each of the Sn-O-Sn oxyge ns is protonated.