Combination between lacunary polyoxometalates and high-nuclear transition metal clusters under hydrothermal conditions: I. from isolated cluster to 1-D chain

Abstract

The hydrothermal reactions of [A-alpha-SiW(9)O(34)](10-)/[A-alpha-PW(9)O(34)](9-) with NiCl(2) x 6H(2)O and amines yielded four unprecedented hybrid high-nuclear Ni-subsituted polyoxotungstates.

Designed Synthesis of POM–Organic Frameworks from {Ni6PW9} Building Blocks under Hydrothermal Conditions

“…Thus, the combination of {Ni 6 } and {PW 9 } units makes {Ni 6 PW 9 (H 2 O) 6 } SBUs excellent candidates for constructing novel POMOFs. As expected, the addition of different rigid carboxylate ligands ( Figure 1 d) to the well-defined {Ni 6 PW 9 (H 2 O) 6 } solutions [8] resulted in the formation of a series of novel POMOFs with 1D, 2D, and 3D frameworks comprising monomeric, dimeric, and infinite SBUs that are derived from the {Ni 6 PW 9 (H 2 O) n } units.…”

“…Although the final residuals (R 1 /wR 2 ) are somewhat large owing to poor crystal quality, the POM backbone and organic ligands are well behaved, and there are no unusual temperature factors in the structure. 4: M r = 3230.23, tetragonal, space group Pbcm, a = 16.6667(5), c = 26.3429 (8) , V = 7307.1 (4) 3 , Z = 4, 1 calcd = 2.936 g cm…”

“…[8] 2) Each {Ni 6 PW 9 (H 2 O) 6 } SBU contains six terminal water ligands that offer the possibility for the design of POMOFs by replacing the water with rigid carboxylates. Notably, the POM-based SBUs can be isolated and are stable in the absence of the carboxylate ligands, [8] which differ from previously used metal carboxylate SBUs that are only stable in the presence of the carboxylate ligands. As shown in Figure 1 a-c, the structure of {Ni 6 PW 9 (H 2 O) 6 } can be described as a trilacunary Keggin B-a-[PW 9 O 34 ] 9À unit capped by a novel triangular [Ni 6 (m 3 -OH) 3 …”

“…We [8] L = en or enMe; en = ethylenediamine, enMe = 1,2-diaminopropane) as SBU on the basis of the following considerations: 1) We have obtained well-defined reaction conditions for the in situ preparation of {Ni 6 PW 9 (H 2 O) 6 } SBUs. [8] 2) Each {Ni 6 PW 9 (H 2 O) 6 } SBU contains six terminal water ligands that offer the possibility for the design of POMOFs by replacing the water with rigid carboxylates.…”

Anisotropic growth of a nickel trimer formed on a highly-stepped TiO2(110) surface

“…The properties of the clusters largely depend on their size and shape. It is becoming possible to control these parameters precisely on an atomic scale using ligands, protecting polymers, structure directing agents and oxide surfaces [6][7][8][9][10]. Coordinately unsaturated metastable clusters are stabilized by metal oxide surfaces and are used as supported metal catalysts [11].…”