Assembly of the Highest Connectivity Wells-Dawson Polyoxometalate Coordination Polymer: the Use of Organic Ligand Flexibility

Abstract

Through tuning the length of flexible bis(triazole) ligands and different metal ion coordination geometries, four Wells-Dawson polyoxoanion-based hybrid compounds, [Cu 6(btp) 3(P 2W 18O 62)].3H 2O ( 1) (btp = 1,3-bis(1,2,4-triazol-1-y1)propane), [Cu 6(btb) 3((P 2W 18O 62)].2H 2O ( 2), [Cu 3(btb) 6(P 2W 18O 62)].6H 2O (btb = 1,4-bis(1,2,4-triazol-1-y1)butane) ( 3), and [Cu 3(btx) 5.5((P 2W 18O 62)].4H 2O (btx = 1,6-bis(1,2,4-triazol-1-y1)hexane) ( 4), were synthesized and structurally characterized. In compound 1, the metal-organic motif exhibits a ladder-like chain, which is further fused by the ennead-dentate [P 2W 18O 62] (6-) anions to construct a 3D structure. In compound 2, the metal-organic motif exhibits an interesting Cu-btb grid layer, and the ennead-dentate polyoxoanions are sandwiched by two Cu-btb layers to construct a 3D structure. Compound 3 exhibits a (4 (2).6 (2).8 (2)) 3D Cu-btb framework with square and hexagonal channels arranged alternately. The hexa-dentate polyoxoanions incorporate only into the hexagonal channels. In compound 4, there exist two sets of (6 (1).10 (2)) 2(6 (1).8 (2).10 (3)) 3D Cu-btx frameworks to generate a 2-fold interpenetrated structure into which the penta-dentate polyoxoanions are inserted to construct a 3D structure. The structural analyses reveal that the length of flexible bis(triazole) ligands and metal ion coordination geometries have a synergic influence on the structures of this series. To our knowledge, they have the highest connectivity for the Wells-Dawson polyoxometalate coordination polymers to date.

A new 2D network constructed by polymeric anions and lanthanides. Synthesis, structure and magnetic property of two new compounds

“…In this field, a remarkable branch is the combination of polyoxometalates (POMs) with metalorganic frameworks (MOFs) to construct multidimensional organicinorganic hybrid materials [8][9][10][11][12]. In recent years, increasing attention has been paid to the design and synthesis of lanthanide-based MOFs due to their unusual coordination characteristics and magnetic properties [13][14][15][16][17][18][19].…”

Three organic–inorganic hybrid complexes based on the Wells–Dawson polyoxoanion

“…1a). Although a [a-P 2 W 18 O 62 ] 6-cluster also coordinates with six transition-metal atoms in the previously reported complex [Cu 3 (btb) 6 (P 2 W 18 O 62 )]Á6H 2 O, the six coordinated oxygen atoms provided by the [a-P 2 W 18 O 62 ] 6-cluster come from two polar and four equatorial WO 6 octahedra in this case [14][15][16]. Each nickel atom in complex 1 adopts distorted octahedral geometry, defined by three terminal oxygen atoms from three [a-P 2 W 18 O 62 ] 6 6-leading to a three dimensional (6, 3)-connected inorganic framework.…”

“…1b). The bond lengths and angles around the copper atoms are 1.88 (2)-1.92 (3) Å for Cu-N, 2.33 (2)-2.42 (2) Å for Cu-O, 168.6 (12)-177.4 (14)°for N-Cu-N, and 87.8(10)-95.4 (9)°for N-Cu-O. Valence sum calculation on the Cu sites in 2 provides an average oxidation state of ?1 [18].…”

“…In the work published to date, the most frequently used POM building blocks are Keggin [5,6], Anderson [7], Mo 8 [8,9], and Mo 6 [10] polyoxoanions, while classical WellsDawson-type POMs are seldom chosen for the construction of organic-inorganic hybrid materials, based on the consideration that their large dimensions (8 9 10 9 12 Å 3 ) may decrease the electron density or the oxygen coordination ability on their surfaces. However, recently some organicinorganic hybrid complexes based on Wells-Dawson-type POMs building block have been reported [11][12][13][14][15][16]. In these complexes, Wells-Dawson-type POMs exhibit diverse coordination modes to transition-metal-organo complex linkers.…”

The first polypseudo-rotaxane structure based on the Wells–Dawson polyoxometalate

“…Bands in the region of 1646À1236 cm À1 are attributed to the characteristic vibration of bix ligands [51,52]. The XRPD patterns for compound 1 are presented in Figure S4.…”