Synthesis of a Tin(II) 1,3-Benzobis(thiophosphinoyl)methanediide Complex and Its Reactions with Aluminum Compounds

The synthesis of a tin­(II) 1,3-benzobis­(thiophosphinoyl)­methanediide
complex and its reactions with aluminum compounds are reported. The
reaction of the 1,3-benzodiphosphole disulfide [1,3-C6H4(PhPS)2CH2] (4)
with [Sn­{N­(SiMe3)2}2] in refluxing
toluene afforded the tin­(II) 1,3-benzobis­(thiophosphinoyl)­methanediide
[{μ-1,3-C6H4(PhPS)2C}­Sn]2 (5). The X-ray crystal structure of 5 shows that it has a 1,3-dimetallacyclobutane structure.
The reaction of 5 with 1 equiv of AlCl3 in
CH2Cl2 afforded [1,3-C6H4(PhPS)2C­(Sn)­{Sn­(SPPh)2C­(AlCl3)-1,3-C6H4}] (6). The reaction
proceeds via an insertion of a AlCl3 molecule into one
of the Sn–C bonds in 5. The reaction of 5 with 2 equiv of AlCl3 in CH2Cl2 afforded [1,3-C6H4(PhPS)2C­(Sn)­(AlCl3)] (7). The reaction appears
to proceed via the formation of compound 6, which then
undergoes an insertion with another AlCl3 molecule to form
compound 7. The transmetalation reaction of 5 with 2 equiv of AlMe3 in CH2Cl2 afforded [1,3-C6H4(PhPS)2CAlMe]2 (8), which contains a terminal Cmethanediide–Al bond.