Synthesis and characterization of two new open-framework zinc phosphites [ M(C 6N 4H 18)][Zn 3(HPO 3) 4] ( M=Ni, Co) with multi-directional intersecting 12-membered ring channels

Abstract

Two new open-framework zinc phosphites, [ M(C 6N 4H 18)][Zn 3(HPO 3) 4] ( M=Ni, Co), have been prepared under hydrothermal conditions. Single-crystal X-ray diffraction analysis shows that [Ni(C 6N 4H 18)][Zn 3(HPO 3) 4] ( 1) and [Co(C 6N 4H 18)][Zn 3(HPO 3) 4] ( 2) are isostructural and both crystallize in the monoclinic space group C2/ c with a = 15.325 ( 3 ) Å , b = 9.792 ( 2 ) Å , c = 14.514 ( 3 ) Å , β = 109.83 ( 3 ) °, V = 2048.8 ( 7 ) Å 3 , Z = 4 , R 1 = 0.0408 ( I > 2 σ ( I ) ), and w R 2 = 0.1104 (all data) for 1, and a = 15.277 ( 2 ) Å , b = 9.8831 ( 13 ) Å , c = 14.534 ( 2 ) Å , β = 109.328 ( 2 ) ° , V = 2070.7 ( 5 ) Å 3 , Z = 4 , R 1 = 0.0380 ( I > 2 σ ( I ) ), and w R 2 = 0.1093 (all data) for 2. The structures of 1 and 2 are built up from strictly alternating ZnO 4 tetrahedra and HPO 3 pseudo-pyramids linked through oxygen vertices to form the three-dimensional (3-D) open-frameworks with multi-directional intersecting 12-membered ring (12-MR) channels. The M(TETA) ( M=Ni, Co) complexes self-assembled under hydrothermal system connect with the inorganic host via M–O–P linkages and interact with inorganic framework through weak H-bonds. The two compounds show intense photoluminescence upon photoexcitation at 235 nm.