Polymerizing Cluster Helicates into High‐Connectivity Networks

Abstract

Solvothermal reactions of CuII salts and 3,5-bis(4-pyridyl)pyrazole (HL) under various conditions gave three different types of crystalline compound, namely [Cu2(Cu5L6)]BF(4).5 H2O (1 a), [Cu2(Cu5L6)]ClO(4).5 H2O (1 b), and [Cu7(CN)2(Cu5L6)2][BF4]3 (2). 1 a and b were obtained in ethanol and NH3.H2O, whereas 2 was obtained in methanol and NH3.H2O. The three complexes were constructed by incorporating new pentanuclear copper(I) pyrazolate bis(triple helical) cluster helicates (Cu5L6) as the second building units (SBUs), in which as many as twelve 4-pyridyl N atoms are available for further coordination and construction of high-connectivity topological networks. In 1 a and b, seven 4-pyridyl N atoms are linked to three three-coordinated CuI atoms and four four-coordinated CuI atoms, which results in 3,4,7-connected networks. In 2, as many as eleven 4-pyridyl N atoms coordinate to eleven CuI atoms, which results in a 4,10-connected topological network. The increasing connectivity of the cluster nodes in 2 is closely related to the in situ-formed CN- anion bridge around the periphery of the pentanuclear cluster helicates. The luminescenct properties of these compounds were also investigated.