Bridging mode flexibility of 1,3-dithiacyclohexane in silver(I) co-ordination polymers

Co-ordination polymers with Ag:1,3-dithiane molar ratios of 1:1, {[Ag-2(1,3-dithiane)(2)][X][Y]}(infinity) (X = Y = NO3, 1; X = Y = PF6, 2; X = Y = BF4, 3; X = BF4, Y = Cl, 4; X = Y = NO2, 5, and 2: 1, {[Ag-2(1,3-dithiane)(SO4)(H2O)(2)].H2O}(infinity) 6, the extended structures of which are 1-D chains and 2-D sheets, respectively, have been synthesised and structurally characterised. The recurrent structural motif is the [Ag-2(mu-1,3-dithiane)(2)](2+) cationic dimer in which two chair-conformation 1,3-dithiane molecules act as two-connecting units to bridge two Ag(I) centres. In 1, 2, and 6, the dimers are linked into near-linear chains by pairs of bridging anions via formation of an Ag2X2 rhomboid dimer. In 3, instead of forming the Ag2X2 (X = F) rhomboid dimer, two [BF4-] anions form mu(2)-F,F'-bridges which support weak Ag-S interactions between cations to give a saw-tooth chain structure. This extra Ag-S contact makes the 1,3-dithiane a three-connecting unit. In 4 and 5, the Ag(I) centres of the cationic dimer are bridged not only by two 1,3-dithiane molecules but also by a Cl- or NO2- anion, respectively, to give [Ag-2(mu-1,3-dithiane)(2)(mu(2)-Cl)](+) (4) and [Ag-2(mu-1,3-dithiane)(2)(mu(2)-O,O'-NO2)](+) (5). In 4, the Cl- anion acts as a mu(4)-bridge to link three [Ag-2(mu-1,3-dithiane)(2)](2+) moieties and generate a zig-zag chain. In 5, one oxygen of the bridging NO2- anions acts as a mu(2)-bridge to link two [Ag-2(mu-1,3-dithiane)(2)](2+) dimers and generate a saw-tooth chain. Although the chains in 1, 2, 3 and 5 are uncharged, that in 4 is cationic and that in 6 is anionic. Charge balance in 4 is maintained by a non-co-ordinated [BF4-] anion; that in 5 is maintained by 'Ag(H2O)(2)(+)', the co-ordination polyhedron of which is completed by sulfur donors from separate 1,3-dithiane molecules, which thus act as four-connecting units, and by two oxygens of separate SO42- anions to give a two-dimensional sheet structure.