Hydrothermal synthesis, structure, and properties of two new nanosized Ln26 (Ln = Ho, Er) clusters

Two new compounds, [Ho26(IN)28(CH3COO)4(CO3)10(OH)26(H2O)18] · 20H2O (1) (HIN = isonicotinic acid) and [Er26(IN)29(CH3COO)3(CO3)10(OH)26(H2O)19] · 26H2O (2), employing the building unit of CO3@Ln26 have been synthesized hydrothermally. Compound 1 crystallizes in the triclinic space group with a = 21.043(4) A, b = 21.128(5) A, c = 35.140(8) A, α = 85.838(3)°, β = 74.909(3)°, γ = 85.414(3)°, V = 15,014(6) A3, Z = 2; 2 crystallizes in triclinic with a = 20.9968(15) A, b = 21.1260(15) A, c = 35.125(3) A, α = 85.9530(10)°, β = 74.7590(10)°, γ = 85.5020(10)°, V = 14,966.3(18) A3, Z = 2. In the structures of both compounds, the isonicotinate (IN) is the main ligand while CH3COO− functions as the second ligand to stabilize the Ln26 cluster; plays a very important role in the formation of the spherical Ln26 cluster. The two compounds are isostructural and have been characterized by single-crystal X-ray diffraction, IR absorption spectroscopy, thermogravimetric analysis, ultraviolet excitation, and emission spectrum.