Poly[dibutylammonium [nonamethylbis(μ3-sulfato-κ3 O:O′:O′′)tristannate(IV)]]

In the structure of the title coordination polymer, {(C8H20N)[Sn3(CH3)9(SO4)2]}n, each of the three SnIV atoms is coordinated in a trigonal–bipyramidal manner by three methyl groups in the equatorial plane and by two O atoms of SO4 2− anions in the axial positions. The μ3-bridging mode of the sulfate anions leads to the formation of corrugated anionic layers parallel to (100). The uncoordinating O atom of one of the two SO4 2− anions is N—H⋯O hydrogen-bonded to the dibutylammonium cation interconnecting the anionic sheets. The structure is partially disordered. The dibutyl ammonium ion is found on two positions with an occupancy ratio of 0.525 (10):0.475 (10), and one sulfate group with three connecting trimethyl stannyl groups is also positionally disordered over two sets of sites with an occupancy ratio of 0.725 (4):0.275 (4).

In the structure of the title coordination polymer, {(C 8 H 20 N)[Sn 3 (CH 3 ) 9 (SO 4 ) 2 ]} n , each of the three Sn IV atoms is coordinated in a trigonal-bipyramidal manner by three methyl groups in the equatorial plane and by two O atoms of SO 4 2À anions in the axial positions. The 3 -bridging mode of the sulfate anions leads to the formation of corrugated anionic layers parallel to (100). The uncoordinating O atom of one of the two SO 4 2À anions is N-HÁ Á ÁO hydrogen-bonded to the dibutylammonium cation interconnecting the anionic sheets. The structure is partially disordered. The dibutyl ammonium ion is found on two positions with an occupancy ratio of 0.525 (10):0.475 (10), and one sulfate group with three connecting trimethyl stannyl groups is also positionally disordered over two sets of sites with an occupancy ratio of 0.725 (4):0.275 (4).
Compound (I) has a polymeric structure consisting of three O 2 SnC 3 moieties, and two different tridentate sulfate ligands ( Fig. 1). In the two-dimensional polymeric structure that extends parallel to (100)

Experimental
(Bu 2 NH 2 ) 2 SO 4 . H 2 O (L) was obtained on mixing a water solution of NH 2 SO 3 H (0.15 g, 1.5 mmol) with Bu 2 NH 2 (0.78 g, 3 mmol). Hydrolysis of NH 2 SO 3 H in basic media has yielded the sulfate. The title compound has been obtained by reacting (L) (0.15 g, 0.4 mmol) with trimethyltin chloride (0.16 g, 0.8 mmol) in ethanol. Slow solvent evaporation yielded colourless crystals. SnMe 3 Cl, the acid NH 2 SO 3 H and Bu 2 NH 2 were purchased from Aldrich and used without further purification.
Disorder is observed for one of the sulfate groups and for the dibutyl ammonium ion. The disorder of the sulfate group extends to the neighboring trimethyl stannyl groups and the occupancy ratio refined to 0.725 (4):0.275 (4). The occupancy ratio for the dibutyl ammonium ion is 0.525 (10):0.475 (10). All equivalent disordered moieties were restrained to have similar geometries (SAME command in SHELXTL). Equivalent methyl groups of trimethyl stannyl groups were restrained to have similar ADPs, as were Sn1 and Sn1B and Sn2 and Sn2B. The disordered atoms N1, N1B, C13, C13B, C14 and C14B of the dibutyl ammonium ion were restrained to be approximately isotropic (ISOR 0.005 command in SHELXTL). Methyl H atoms were placed onto calculated positions and refined using a riding model, with C -H distances of 0.98 Å and U iso (H)= 1.5U eq (C); methylene H atoms were refined with C-H distances of 0.99 Å and U iso (H)= 1.2U eq (C); ammonium H atoms were refined with N-H distances of 0.90 Å and U iso (H)= 1.2U eq (N).

Figure 1
The asymmetric unit of the structure of compound (I) with displacement ellipsoids drawn at the 50° probability level. The minor components of the disordered parts within the structure are not shown.

Figure 2
The two-dimensional [(SnMe 3 ) 3 (SO 4 ) 2 ]anionic sheet structure of (I). Hydrogen atoms and the Bu 2 NH 2 + cations have been omitted for clarity. The minor components of the disordered parts within the structure are not shown.

Figure 3
The linking of the sheets through N-H···O hydrogen bonds between the Bu 2 NH 2 + cations and the stannate(IV) sheets (red dotted lines). Only H atoms involved in hydrogen bond interactions are shown for the sake of clarity.

Poly[dibutylammonium [nonamethylbis(µ 3 -sulfato-κ 3 O:O′:O′′)tristannate(IV)]]
Crystal data (C 8 H 20   where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.004 Δρ max = 0.76 e Å −3 Δρ min = −0.46 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.