Synthesis, structure, and characteristics of a hexa-Ti-oxo-cluster-added Keggin-type polyoxometalate

Abstract

An acentric hexa-Ti-oxo-cluster-added trimeric phosphotungstate, [H 2 N(CH 3 ) 2 ] 3 H 12 [Ti 6 O 6 (A-α-1,2-PW 10 O 37 ) 3 ]•12 H 2 O (1), was synthesized by reacting trivacant polyoxometalate (POM) fragments with Ti 4+ ions under hydrothermal conditions and characterized via single-crystal/powder X-ray diffraction, solid UV-vis and IR spectroscopies, and thermogravimetric analysis. The polyoxoanion of 1 is constituted by three Ti 2 O 3 (A-α-1,2-PW 10 O 37 ) subunits linked through Ti-O-Ti bonds, forming a ringshaped configuration. Furthermore, 1 exhibits a second-harmonic generation response about 0.6 times that of KH 2 PO 4 , which paves the way toward the development of Ti-added POMs in the field of nonlinear optical materials.

New two fold interpenetrating 3D polyoxovanadate-based metal–organic framework as bifunctional catalyst for the removal of 2-chloroethyl ethyl sulfide and phenolic compounds

“…Polyoxometalates (POMs), a type of inorganic metal oxide cluster with tremendous architectural diversity, exhibit attractive properties [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. As an important branch of the POM family, polyoxovanadates (POVs) have attracted increasing attention because of their diverse structures and remarkable properties.…”

Synthesis and Characterization of 6-Ti-Substituted Polyoxomolybdate with High Catalytic Activity for Sulfide Oxidation

“…Going back to 1983, Knoth’s group published the first instance of TiSPs [PW 11 TiO 40 ] 5– . Subsequent efforts have concentrated on synthesizing diverse TiSPs, including monomeric clusters [TiW 11 PO 40 ] 5– and α 2 -[P 2 W 17 (TiO 2 )­O 61 ] 8– , , dimeric clusters [A-β-Si 2 W 18 Ti 6 O 77 ] 14– and [Ti 8 (C 2 O 4 ) 8 P 2 W 18 O 76 (H 2 O) 4 ] 18– , , trimeric clusters [Ti 6 O 6 (A-α-1,2-PW 10 O 37 ) 3 ] 15– and [(α-Ti 3 SiW 9 O 37 OH) 3 (TiO 3 (OH 2 ) 3 )] 17– , , tetrameric clusters [{β-Ti 2 SiW 10 O 39 } 4 ] 24– , [{K 2 Na­(H 2 O) 3 }@{(Ti 2 O) 2 (Ti 4 O 4 ) 2 (A-α-1,3,5-GeW 9 O 36 ) 2 (A-α-2,3,4-GeW 9 O 36 ) 2 }] 25– , and [(Cs@Ti 12 O 18 )@{(A-α-SiW 9 O 34 )­(P 2 W 15 O 56 ) 3 }] 33– , − and multimeric clusters (Ti 2 P 2 W 15 ) 2 (Ti 2 P 2 W 16 ) 2 (P 2 W 11 ) 2 . However, the investigation of TiSPs is still in its early stages compared with their polyoxotungstate counterparts.…”

Three Double-Layered {Ni8}@{Bn}2 (n = 3, 4, 6) Cluster Sandwiched Polyoxometalates

“…Polyoxometalates (POMs) are of metal-oxide clusters, possessing unrivaled structural diversity and demonstrating great potential in a wide range of fields, including catalysis, biomedicine, magnetism, and materials science. − Within the class of transition-metal added POMs (TMAPs), , sandwiched structures built by two lacunary POM fragments linked by a diverse and versatile TM-oxo clusters (TMOCs) are rather prominent. The research on sandwiched TMAPs can be traced back to 1973, when [Co 4 (H 2 O) 2 (PW 9 O 34 ) 2 ] 10– was made, followed by numerous reports on sandwiched TMAPs with various TMOCs, directly resulting in the largest sandwiched subclass. − However, the number of TM centers embedded in the sandwich belts is usually less than six, primarily because the vacant sites of lacunary POM units are saturatedly occupied by TM ions so as to hardly combine with more TM cations and in situ generated larger TMOCs in the sandwich belt become unstable without the assistance of extraneous structure-stabilizing agents such as phosphate, carbonate, or small organic ligands. Thus, the assembly of high-nuclear TMAPs by increasing the number of TM cations in the central sandwich area is still a particularly attractive focus of ongoing research.…”