Open-Framework Zinc Phosphates Synthesized in the Presence of Structure-Directing Organic Amines

Treatment of A2CO3 (A=K, Rb) with Sn and Se in an H2O/CH3OH mixture at 130°C affords reaction solutions from which respectively K4Sn4Se10·4.5H2O (1) and Rb4Sn4Se10·1.5H2O (2) can be isolated on cooling. 1 crystallizes in the rhombohedral space group R with a=b=15.320(3) ?, c= 21.019(7) ?, Z=6, V=4272(2) ?3, 2 in the same space group with a=b=15.539 (2) ?, c=21.373(4) ?, Z=6, V=4469.4(13) ?3. These isotypic phases contain lamellar 2infinity[Sn4Se4-10] polyanions in which SnSe4-4 and [Sn2Se6]4- molecular building units are corner-bridged into a 63 net with 36-membered cavities of 1.3× 1.4 nm cross-section. Cs4Sn4Se10·3.2H2O (3) can be prepared under similar mild solventothermal conditions. It crystallizes in the triclinic space group P with a=7.235(1) ?, b=9.468(2) ?, c=11.235(2) ?, alpha=68.77(3)°, beta=83.25(3)°, gamma=84.53(3)°, Z=1, V=711.2(2) ?3. In contrast to the 2-dimensional anions of the same formula type in 1 and 2, the 2infinity[Sn4Se4-10] polyanions of 3 consist of 1infinity[SnSe2-3] ribbons that are corner-bridged through ditetrahedral [Sn2Se6]4- units into sheets with smaller 20-membered pores. The role of starting pH, cation size and temperature on the construction of lamellar selenidostannates(IV) are discussed. infinity