Role of Chains in the Formation of Extended Framework Tin(II) Phosphates and Related Materials

The reactions of tin(II) chloride with phosphonic and phosphinic acids under hydrothermal
conditions result in structures with varying dimensionalities. The synthesis and characterization of eight new structures is described. SnCl(HPhPO2), I, triclinic, P1̄ (No. 2), has lattice
parameters a = 5.4767(6) Å, b = 8.8106(9) Å, c = 9.5219(10) Å, α = 104.564(2)°, β = 95.440(2)°, γ = 99.349(2)°, and V = 434.34(8) Å3. (SnCl)2MePO3, II, triclinic, P1̄ (No. 2), has a =
4.7275(17) Å, b = 6.152(2) Å, c = 13.632(5) Å, α = 81.299(7)°, β = 89.052(7)°, γ = 89.781(7)°,
and V = 391.8(3) Å3. Sn2Cl(EtPO3)EtPO2OH, III, monoclinic, P21/m (No. 11), has a = 4.814(4) Å, b = 8.530(4) Å, c = 15.214(8) Å, β = 99.09(10)°, and V = 616.9(7) Å3. β-SnEtPO3, IV,
monoclinic, Cc (No. 9), has a = 4.6415(13) Å, b = 18.695(5) Å, c = 6.4964(18) Å, β = 99.907(4)°, and V = 555.3(3) Å3. SnMePO3, V, monoclinic, P21/c (No. 14), has a = 4.5998(7) Å, b =
15.430(2) Å, c = 6.5861(10) Å, β = 100.719(3)°, and V = 459.30(12) Å3. Sn2(O3P(CH2)2PO3),
VI, monoclinic, P21/c (no. 14), has a = 4.6435(6) Å, b = 13.4512(16) Å, c = 6.4767(8) Å, β =
100.258(2)°, and V = 398.07(9) Å3. SnPO3CH2COOH, VII, monoclinic, P21/n (No. 14), has a
= 5.490(2) Å, b = 4.890(2) Å, c = 21.884(9) Å, β = 90.505(7)°, and V = 587.4(4) Å3. (NH4)2Sn(O3PCH2PO3), VIII, orthorhombic, Pbca (No. 61), has a = 10.3417(10) Å, b = 10.0475(10)
Å, c = 16.9927(17) Å, and V = 1765.7(3) Å3. For the first time, a three-ring (3R) phosphonate
chain and an open-chain (i.e., no rings) phosphinate “wire” have been isolated. The phosphate
analogues of these structures serve as key structural motifs in tin(II), zinc(II), and cobalt(II) phosphates, underscoring their role in the formation of framework phosphates. We
propose that metal phosphate wires could play an important role in the formation of open-framework materials.