Self-Assembly of a CsCl-like 3D Supramolecular Network from [Zn₆(HL)₆(H₂L)₆]⁶⁺ Metallamacrocycles and (H₂O)₂₀ Clusters (H₂L = 4-(2-Pyridyl)-6-(4-pyridyl)-2-aminopyrimidine)

The reaction of Zn(NO 3 ) 2 ·6H 2 O with multifunctional ligand 4-(2-pyridyl)-6-(4-pyridyl)-2-aminopyrimidine (H 2 L) leads to a circular hexanuclear zinc complex [Zn 6 (HL) 6 (H 2 L) 6 ](NO 3 ) 6 ·26H 2 O ( 1 ), confirmed by single-crystal X-ray diffraction. In the [Zn 6 (HL) 6 (H 2 L) 6 ] 6+ cation, six zinc centers are arranged in a chairlike conformation and 12 ligands fulfill bridging and terminal functions, respectively. The particular interest of complex 1 is the formation of a unique water cluster (H 2 O) 26 composed of a clathrate (H 2 O) 20 core and six dangling water molecules, and the clathrate (H 2 O) 20 core is structurally similar to the famous “Bucky water” (H 2 O) 20 . Furthermore, the water molecules and the nitrate ions are assembled into an interesting negative three-dimensional (3D) framework through hydrogen bonds, and the [Zn 6 (HL) 6 (H 2 L) 6 ] 6+ cations just locate in the cavities of the anionic 3D network. To gain insight into the stability of (H 2 O) 20 observed in complex 1, we isolate the water cluster from its environments and compare its stability with “Bucky water” (H 2 O) 20 by a theoretical calculation method. Complex 1 displays room temperature photoluminescence.