Three Polymeric Frameworks Constructed from Discrete Molybdenum Oxide Anions and 4,4‘-bpy-Bridged Linear Polymeric Copper Cations

Abstract

Three compounds, [Cu(4,4‘-bpy)] 2 MoO 4 ·2H 2 O ( 1 ), [Cu(4,4‘-bpy)] 2 Mo 2 O 7 ( 2 ), and [Cu(4,4‘-bpy)(nic)(H 2 O)] 2 Mo 8 O 26 ( 3 ), are synthesized by hydrothermal reaction, which suggests that oxomolybdate−organic ligand coordination transition-metal fragments can merge their merit to generate some interesting architectures. Crystal data for [Cu(4,4‘-bpy)] 2 MoO 4 ·2H 2 O ( 1 ): monoclinic system, space group C 2/ c, a = 10.936(1), b = 17.775(1), and c = 14.484(1) Å, β = 110.15(1)°, and Z = 4. Crystal data for [Cu(4,4‘-bpy)] 2 Mo 2 O 7 ( 2 ): orthorhombic system, space group Pbcn, a = 11.841(1), b = 9.105(1), and c = 21.311(1) Å, and Z = 4. Crystal data for [Cu(4,4‘-bpy)(nic)(H 2 O)] 2 Mo 8 O 26 ( 3 ): monoclinic system, space group P 2(1)/ n, a = 11.457(1), b = 16.918(1), and c = 12.463(1) Å, β = 92.6(1)°, and Z = 2. Compound 1 is built up from {MoO 4 } tetrahedra linking of 4,4‘-bpy coordination copper(I) chain fragments as a railroad-like framework. Compound 2 has noticeable structural features: two {Mo 2 O 7 } and four {CuO 2 N 2 } tetrahedra are connected to each other alternately in a pattern of corner sharing to construct an eight-metal-central-membered cavity; such subunits are connected to each other also through corner-shared, two-dimensional mosaic frameworks, which are linked further by bidentate 4,4‘-bpy ligands to a three-dimensional framework with oval channels. The two-dimensional flat brick wall-like layer structure of 3 is constructed from two layer [Cu(4,4‘-bpy)(nic)(H 2 O)] n 2 n + chains joined together by β-[Mo 8 O 26 ] 4 - units as tethers through covalent bonding of the terminal oxo groups to form rectangular cavities. The most curious feature of 3, however, is that the extended structure of 3 is comprised of an interpenetrated arrangement of two kinds of multizigzag chain polymers entangled together. The successful assembly of the three polymeric frameworks of 1 − 3 demonstrates the dramatic influence of the reaction acidity/basicity on the organization of molecular building groups and further on the construction of solid architectures. The studies of the temperature dependence of the magnetic susceptibilities of 3 reveal that there exists the weak magnetic transformation of 4,4‘-bpy and octamolybdate between metal ions.