Solvothermal Syntheses and Characterization of a Series of New Selenidostannates with Lanthanide Complexes as Counterions

A series of lanthanoid selenidostannates [Gd(dap)4]2[Sn2Se6]Cl2 (1, dap = 1,2-diaminopropane) and [Ln(dap)4]2[Sn2Se6]Cl2·H2O {Ln = Tb (2a), Dy (2b) and Er (2c)} have been solvothermally synthesized and structurally characterized. Both 1 and 2a–c are composed of [Ln(dap)4]3+ complex cations, [Sn2Se6]4− anions built up from two [SnSe4] tetrahedra sharing a common edge, and Cl− ions. The [Ln(dap)4]3+ complex cations and Cl− anions in 1 and 2a–c are connected via the N–H···Cl hydrogen-bond interactions forming 1-D helical chain and 2-D layer, respectively. Their optical properties have been investigated by UV–Vis spectra, and density functional theory calculation of 1 has been performed.