Inorganic–organic hybrid high-dimensional polyoxotantalates and their structural transformations triggered by water

Abstract

In this work, novel dimeric polyoxotantalate (POTa) clusters {Cu(en)(Ta6O19)}2/{Cu(enMe)(Ta6O19)}2 were introduced as SBUs to construct a new family of extended POTa materials, including the first two 3D POTa frameworks and two 2D POTa layers.

Synthesis and Selected Properties of New Complex Cation Decorated Polyoxotantalates

“…Taking all O···O separations below 3.04 Å as possible hydrogen bonding interactions into account (Figure S9), three water cluster motifs can be identified: a discrete R4 ring, a D3 chain, and an infinite tape [2T4(2)­T5(2)­T6(2)­T4(1)]­2A(0) (Figure S9). The cross-linking of the clusters occurs via O water –O cluster hydrogen bonds with bond lengths between 2.671 and 3.039 Å (Table S10).…”

“…POTas were also successfully prepared with d-block metal cations (M n + ) including Rh 2+ , Ru 2+ , Ir 2+ , Re + , Mn + , Cu 2+ , Ti 4+ , Co 2+ , and Ni 2+ ,,− or lanthanide cations . But only in a few structures, the M n + cations expand the {Ta 6 O 19 } moiety via M–O covalent bonds such as in {[Cu­[1,3-dap) 2 ] 2 [Cu­(1,3-dap)­(H 2 O)] 2 [Ta 6 O 19 ]}·8H 2 O, {[Cu­(en) 2 ] 4 [Ta 6 O 19 ]}·14H 2 O, H 2 {[Cu­(en) 2 ] 3 [Cu­(en)­(H 2 O) 2 Cu­(en)­(Ta 6 O 19 )] 2 }·30H 2 O, Na 4 K 6 [(Ta 6 O 19 )­Co­(en) 2 ]·30H 2 O, and K 2 [Ni­(dien) 2 ]­{[Ni­(dien)] 2 Ta 6 O 19 }·11H 2 O. ,,− The few rare examples presented here indicate that integration or covalent expansion of POTas by M n + cations is a challenge, which may be at least partially explained by the high pH value required for product formation, leading possibly to M hydroxides. But in the last years, it has been shown that the integration of different and advanced cations in POMs is of essential importance when it comes to structural design, specification, and properties of the material .…”

Synthesis and crystal structure of bis[μ-N,N-bis(2-aminoethyl)ethane-1,2-diamine]bis[N,N-bis(2-aminoethyl)ethane-1,2-diamine]-μ4-oxido-hexa-μ3-oxido-octa-μ2-oxido-tetraoxidotetranickel(II)hexatantalum(V) nonadecahydrate

“…It turned out that the use of water-soluble compounds as precursor materials is more effective for generating new compounds, which opens the possibility of developing more efficient syntheses at room temperature (Dopta et al, 2020;Mahnke et al, 2018a,b). Some transition metal (TM) decorated POTas have also been synthesized by slow crystallization at room temperature (Guo et al, 2011;Li et al, 2019), which is characterized by long reaction times and high sensibility for parameter changes during reaction. To overcome these drawbacks, we were interested in the possibility of faster crystallization times.…”

Organoamine-Directed Assembly of 5p–4f Heterometallic Cluster Substituted Polyoxometalates: Luminescence and Proton Conduction Properties

“…Polyoxometalates (POMs), as an intriguing and distinctive category of anionic metal-oxide clusters comprising early transition metals in high oxidation states such as V V , Nb V , Ta V , Mo VI , and W VI , − have attracted increasing attention due to their versatile structural configurations and potential applications in various fields, such as catalysis, , magnetism, medicine, and material sciences. − Compared with isopolyanions, heteropolyanions contain a heteroatom X, which often features a tetrahedral configuration (e.g., PO 4 , SiO 4 ) or a trigonal pyramid configuration with the lone-pair electrons (e.g., As III O 3 , Sb III O 3 ) . The existence of the lone pair of electrons precludes the formation of the plenary Keggin-type ions, thus providing a greater possibility for constructing unprecedented structures with new properties .…”