Employing Zinc Clusters as SBUs To Construct (3,8) and (3,14)-Connected Coordination Networks: Structures, Topologies, and Luminescence

Two new metal–organic frameworks (MOFs), [Zn 2 (OH)(cpia)(bipy) 0.5 ] n ( 1 ) and {[Zn 7 (OH) 2 (HOMe) 2 (cpia) 4 (bib)] · 5H 2 O} n ( 2 ) (bib = 1,4-bis(imidazol-1-yl)benzene, H 3 cpia = 5-(4-carboxyphenoxy)isophthalic acid, bipy = 4,4′-bipyridine), have been solvothermally synthesized and structurally characterized. Both of them are based on zinc clusters as secondary building units (SBUs). Compound 1 presents an interesting three-dimensional 2-fold interpenetrated (3,8)-connected network constructed from tetranuclear [Zn 4 (OH) 2 ] 6+ clusters with (4 3 ) 2 (4 6 ·6 18 ·8 4 ) topology, while compound 2 can be described as a (3,14)-connected framework built from an unprecedented heptanuclear [Zn 7 (OH) 2 (HOMe) 2 ] 12+ cluster with {(4 20 ·6 52 ·7 6 ·8 13 )(4 3 ) 4 } topology. Detailed structural comparison of two compounds indicated that coligands play significant roles in tuning the nuclearity of metal clusters and the connectivity of specific networks. Furthermore, the thermal stabilities and luminescence properties of two compounds reveal that they all exhibit high thermal stability and strong luminescence emission bands in the solid state at room temperature.