On an octastannanediide R*Sn-6(8)[Na(THF)(2)](2) and the possible existence of an octastannane R*Sn-6(8)

The black, air and moisture sensitive octastannanediide R*Sn-6(8) [Na(THF)( 2)](2) (4) (R* = SitBu(3)) is prepared by reaction of Sn[N(SiMe3)(2)](2) wi th R*Na in tBuOMe at -78 degrees C. Red brown of octastannane R*Sn-6(8) (5) is formed by thermolysis of the tristannacyclopropene R*Sn-4(3) in benzene at 100 degrees C. According to the result of the X-ray structural analysis , 4 contains a Sn-8 cubane with six Sn atoms each connected with R* and two at the end of a space diagonal connected with Na(THF)(2). A preliminary X- ray structure analysis shows 5 to adopt the same Sn cubane structure as 4 w ith two bare Sn atoms at the end of a space diagonal.