Hydrothermal synthesis, crystal structure and properties of a 3D-framework polyoxometalate assembly: [Ag(4,4′-bipy)](OH){[Ag(4,4′-bipy)]2[PAgW12O40]}·3.5H2O

Keggin POMs Modified by Bonding to Multitrack Cu(bipy) Chains through Linearly Arrayed Terminal and Bridging Oxygen Atoms of the M3O13 Triad

“…Single-crystal X-ray diffraction analysis reveals that 1 consists of one [SiMo 12 4-possesses the classical α-Keggin-type structure without disorder. [18] The tetrahedrally coordinated Si is surrounded by four oxygen atoms with Si-O bonds ranging from 1.624 (7) 4-anion, which is similar to the coordination mode of {Cu 3 (4,4Ј-bpy) 3 [19] In this way, each 4,4Ј-bipy ligand links two symmetrical Cu I atoms into a one-dimensional Cu (Figure 3a), which is in the van der Waals interaction range.…”

“…4-(SiW 12 ) cluster as a pendant hexadentate ligand covalently bonded to four Cu I (4,4Ј-bipy) subunits and forms a 2D net-texture structure with a large vacancy (30.9 ϫ 10.6 Å), and the 2D layers are arranged in a parallel staggering fashion to form a 3D framework.…”

“…[3] Recently, a number of Keggin POMs covalently modified by transition-metal complexes have been reported, such as the mixed-valent compounds [{Cu 4 (terpy) 4 4 )}]· 5H 2 O described by Zubieta et al, [4] [PW 12 O 40 ·Ni(2,2-bipy) 2 -(H 2 O)] 3-by Xu et al, [5] and (NH 4 [6] the controlled assembly from lacunary Keggin POMs has also been reported by Pope et al [7] and Gutiérrez-Zorrilla et al [8] All these compounds featured sufficient charge density on the Keggin anion surface atoms to coordinate the transition-metal complexes. It is believed that surface activation is achieved by reducing the metal centres or by replacing metal centre(s) with a high oxidation state by other lower-valence metal(s).…”

“…However, there are only a few examples of fully oxidized Keggin POMs modified by transition-metal complexes. These examples include the unsymmetrical discrete complex [{Cu 2 (O 2 CMe) 2 (5,5-dimethyl-2,2-bipy) 2 }{Cu(5,5Ј-dimethyl-2,2Ј-bipy) 2 }SiW 12 O 40 ], [9] the 1D framework [Ag 3 (2,4Ј-bipy) 3 -PMo 12 O 40 ], [10] the 3D framework complexes [Cu 3 (pz) 3 -(PW 12 O 40 )], [11] [Ag 3 (pz) 3 (PW 12 O 40 )], [11] [Ag(4,4-bipy)](OH)-[{Ag(4,4-bipy)} 2 {PAgW 12 O 40 }], [12] and KH 2 [(-C 5 H 8 NO 2 ) 4 -(H 2 O)Cu 3 ][BW 12 O 40 ]. [13] In the last framework, chirality was designed into the helical motif.…”

“…The challenge is really to demonstrate control and expendability, to optimise the physical properties, etc. In this paper, we select the ligand 4,4Ј-bipy and the Cu ion to build metal-organic complex subunits in the hope of forming an extended structure of Keggin POMs modified by transition-metal complex moieties with little steric crowding, and we report the hydrothermal syntheses and crystal structures of two novel Cu(4,4Ј-bipy) modified Keggin derivatives, [{Cu(4,4Ј-bipy)} 3 {α-HSiMo 12 …”