Polyoxometalate-based metal organic frameworks (POMOFs): structural trends, energetics, and high electrocatalytic efficiency for hydrogen evolution reaction.

The grafting of the triangular 1,3,5-benzene tricarboxylate linkers (denoted trim) on tetrahedral ε-Keggin polyoxometalates (POMs) capped by Zn(II) ions, formed in situ under hydrothermal conditions, has generated three novel POM-based metal organic frameworks (POMOFs). (TBA)(3)[PMo(V)(8)Mo(VI)(4)O(36)(OH)(4)Zn(4)][C(6)H(3)(COO)(3)](4/3)·6H(2)O (ε(trim)(4/3)) is a 3D open-framework built of molecular Keggin units connected by trim linkers, with channels occupied by tetrabutylammonium (TBA) counterions. ε(trim)(4/3) is a novel (3,4)-connected net, named ofp for open-framework polyoxometalate, and computer simulations have been used to evaluate its relative stability in comparison with ctn- and bor-like polymorphs, showing the stability of this novel phase directly related to its greatest density.

Polyoxopalladates encapsulating yttrium and lanthanide ions, [X(III)Pd(II)12(AsPh)8O32]5- (X=Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu).

A series of novel yttrium- and lanthanide-containing heteropolyoxopalladates have been prepared and isolated as hydrated sodium salts, Na(5)[X(III)Pd(II)(12)(AsPh)(8)O(32)]y H(2)O (X=Y (1), Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), Tb (7), Dy (8), Ho (9), Er (10), Tm (11), Yb (12), Lu (13); y=15-27). The polyanions [X(III)Pd(II)(12)(AsPh)(8)O(32)](5-) consist of a cuboid framework of twelve Pd(II) ions with eight phenylarsonate heterogroups located at the vertices and a central guest ion X. The compounds 1-13 have been prepared in a simple one-pot self-assembly reaction of Pd(CH(3)COO)(2), phenylarsonic acid and the respective salt of the element X in 0.

Cobalt, manganese, nickel, and vanadium derivatives of the cyclic 48-tungsto-8-phosphate [H(7)P(8)W(48)O(184)](33-).

The cobalt(II) containing tungstophosphate [Co(4)(H(2)O)(16)P(8)W(48)O(184)](32-) (1) has been synthesized by addition of Co(2+) ions to an aqueous solution of [H(7)P(8)W(48)O(184)](33-) (P(8)W(48)) and characterized by single-crystal XRD, IR, and UV-vis spectroscopy, elemental analysis, electrochemistry, and magnetochemistry. The novel polyanion 1 is a derivative of the superlacunary P(8)W(48) with four cobalt(II) ions coordinated to the rim of the central cavity and two additional cobalt(II) ions linked on the outside bridging neighboring polyanions. Using similar synthetic procedures, but adding a few drops of H(2)O(2), we isolated the manganese(II) derivative [Mn(4)(H(2)O)(16)(P(8)W(48)O(184))(WO(2)(H(2)O)(2))(2)](28-) (2) and its nickel(II) analogue [Ni(4)(H(2)O)(16)(P(8)W(48)O(184))(WO(2)(H(2)O)(2))(2)](28-) (3).

Capture of the [Mo3S4]4+ cluster within a {Mo18} macrocycle yielding a supramolecular assembly stabilized by a dynamic H-bond network.

The use of the [Mo(3)S(4)(Hnta)(3)](2-) complex (nta(3-) = nitrilotriacetate) as structuring agent toward the self-condensation process of the [Mo(2)O(2)S(2)(OH(2))(6)](2+) cation leads to the largest oxothiomolybdenum ring. In the solid state, X-ray diffraction analysis reveals the presence of the targeted molecular compound (noted 1a), which consists of the {Mo(18)O(18)S(18)(OH)(18)} host templated by the [Mo(3)S(4)(Hnta)(3)](2-) guest. Nevertheless, the structure shows an additional molecular moiety corresponding to a dinuclear unit {Mo(2)O(2)S(2)} coordinated to two nta(3-) ligands, mutually arranged in a cis fashion (1b).

Wheel-shaped Cu(20)-tungstophosphate [Cu(20)X(OH)(24)(H(2)O)(12)(P(8)W(48)O(184))](25-) ion (X = Cl, Br, I) and the role of the halide guest.

We have synthesized the known [Cu(20)Cl(OH)(24)(H(2)O)(12)(P(8)W(48)O(184))](25-) (1) and report here its bromide and iodide analogues, [Cu(20)Br(OH)(24)(H(2)O)(12)(P(8)W(48)O(184))](25-) (2) and [Cu(20)I(OH)(24)(H(2)O)(12)(P(8)W(48)O(184))](25-) (3). These polyanions were characterized in the solid state by IR spectroscopy and single-crystal X-ray diffraction. Magnetic susceptibility and magnetization data over 1.

Self-assembly of star-shaped heteropoly-15-palladate(II).

A novel heteropolyoxopalladate structural type has been discovered: the polyoxo-15-palladate(II) [Pd(0.4)Na(0.6) subsetPd(15)P(10)O(50)H(6.

Zeolitic polyoxometalate-based metal-organic frameworks (Z-POMOFs): computational evaluation of hypothetical polymorphs and the successful targeted synthesis of the redox-active Z-POMOF1.

The targeted design and simulation of a new family of zeolitic metal-organic frameworks (MOFs) based on benzenedicarboxylate (BDC) as the ligand and epsilon-type Keggin polyoxometalates (POMs) as building units, named here Z-POMOFs, have been performed. A key feature is the use of the analogy between the connectivity of silicon in dense minerals and zeolites with that of the epsilon-type Keggin POMs capped with Zn(II) ions. Handling the epsilon-Keggin as a building block, a selection of 21 zeotype structures, together with a series of dense minerals were constructed and their relative stabilities computed.

Heteropoly-13-palladates(II) [Pd(II)(13)(As(V)Ph)(8)O(32)](6-) and [Pd(II)(13)Se(IV)(8)O(32)](6-).

Two discrete anionic palladium(II)-oxo clusters have been prepared: [Pd(13)(As(V)Ph)(8)O(32)](6-) (1) and [Pd(13)Se(IV)(8)O(32)](6-) (2) were synthesized in one-pot self-assembly reactions of Pd(OAc)(2) with PhAsO(3)H(2) and SeO(2) and characterized by single-crystal X-ray analysis, IR, thermogravimetric analysis, elemental analysis, magnetic and electron paramagnetic resonance measurements, and electrochemistry.

Magnetic bistability of individual single-molecule magnets grafted on single-wall carbon nanotubes.

A POM to remember: Hexanuclear Fe(III) polyoxometalate (POM) single-molecule magnets (see structure) can be noncovalently assembled on the surface of single-wall carbon nanotubes. Complementary characterization techniques (see TEM image and magnetic hysteresis loops) demonstrate the integrity and bistability of the individual molecules, which could be used to construct single-molecule memory devices.