A Series of 1-D Lanthanide Coordination Polymers Based on [Ln4(μ3-OH)4] (Ln = Er, Tb, Gd) Cluster Units

Abstract

A series of 1-D lanthanide coordination polymers [Ln(μ3-OH)(pybz)(pa)] n (Ln = Er (1), Tb (2), Gd (3), Hpybz = 4-pyridin-4-yl-benzoic acid, Hpa = 2-picolinic acid) based on [Ln4(μ3-OH)4] cluster units have been hydrothermally synthesized and characterized by single crystal X-ray diffraction, IR, elemental analysis, and thermogravimetric analysis. X-ray crystal structure analyses reveal that 1–3 are isomorphous with tetragonal space group P $$ \overline{4} $$ 21c and comprise tetranuclear Ln–O clusters, in which four Ln3+ centers are joined together by four μ3-bridging hydroxyl groups to form cubane-like [Ln4(μ3-OH)4]8+ cores that are further linked by four μ3-pa− ligands to produce 1-D chains along the c-axis. A series of 1-D lanthanide coordination polymers [Ln(μ3-OH)(pybz)(pa)] n (Ln = Er (1), Tb (2), Gd (3), Hpybz = 4-pyridin-4-yl-benzoic acid, Hpa = 2-picolinic acid) based on [Ln4(μ3-OH)4] cubanes have been hydrothermally synthesized. For this compound, tetranuclear cubane-like clusters [Ln4(μ3-OH)4]8+ composed of four Ln3+ centers as building blocks are further assembled into 1-D chains along the c-axis.