A discrete unsymmetrically substituted dihydrodioxadistannetane with both η1 and intramolecular η2μ2 sulfonate bondings

Hydrolysis of the aryltripropynyltin (3) in the presence of an arylsulfonic acid resulted in the formation of a new tetrasulfonato 1,3-dihydro-1,3-dioxa-2,4-diaryl-2,4-distannetane (4). Its crystal structure revealed that the molecule is the smallest discrete tin sulfonate cluster reported up to now with absence of intermolecular interactions. Molecule 4 also exhibits unusual η1 and intramolecular η2μ2 bonding modes for the sulfonate groups. Moreover, while only symmetrical 1,3-dihydro-1,3-dioxa-distannetanes have been described so far, the tin atoms in 4 are differently substituted.