Structural variations of SnII pyridylphosphonates influenced by an uncommon Sn–N interaction

Four new SnII phosphonates have been synthesized by hydrothermal methods, and their structures determined by single-crystal X-ray diffraction. Tin(II) 3-pyridylphosphonate, SnO3PC5H4N (I), crystallizes in P21/c with a=4.9595(8) Å, b=10.7673(18) Å, c=13.996(2) Å, and β=93.616(2)°. Tri-tin(II) (μ-3)-oxo-(bis)-4-pyridylphosphonate, Sn3O(O3PC5H4N)2 (II), crystallizes in P-1 with a=7.2406(14) Å, b=9.9524(19) Å, c=12.604(3) Å, α=104.510(11)°, β=90.326(11)°, and γ=110.897(11)°. Tin(II) 6-methyl-2-pyridylphosphonate quadrahydrate, Sn(O3PC5H3NCH3)·0.25H2O (III), crystallizes in Pna21, a=18.955(3) Å, b=9.7543(14) Å, and c=17.833(3) Å. Tin(II) 4-cyanophenylphosphonate, Sn(O3PC6H4CN) (IV), crystallizes in P-1, a=5.0019(3) Å, b=8.4396(5) Å, c=10.3099(6) Å, α=90.352(3)°, β=94.894(3)°, and γ=92.236(4)°. I, II, and IV have ladder-type structures, and III is a layered compound. The structural variations show the effects of the Sn–N interaction on the final structures.