Pd-katalysierter Deuterium-Austausch am Octa(silsesquioxan)H8Si8O12 zu D8Si8O12

Pd-Catalyzed Deuterium Exchange of Octa(silsesquioxane) H₈Si₈O₁₂ to D₈Si₈O₁₂ Deuterium exchange on octa(silsesquioxane) H₈Si₈O₁₂ to D₈Si₁₈O₁₂ catalyzed by palladium on carbon is reported.     

A quantum chemical study of silsesquioxanes: H8Si8O12, Me8Si8O12, H@Me8Si8O12, He@Me8Si8O 12 + , and He@Me8Si8O12

Quantum chemical PBE0 and B3LYP/cc-pVTZ, PBE0, B3LYP, RHF and MP2/6-31G(d,p) methods are employed to calculate the structural parameters of octa(silsesquioxane) H₈Si₈O₁₂ and octa(methylsilsesquioxane) Me₈Si₈O₁₂. These molecules and complexes H@Me₈Si₈O₁₂, He@Me₈Si₈O ₁₂ ⁺ , and He@Me₈Si₈O₁₂ have highly symmetric (O _h ) equilibrium configurations. With the use of the PBE0 method and a cc-pVTZ multicenter basis set common for the complex and its components coincidence is achieved between the calculated polarizability of a free He atom and the experimental value of 0.21 ų and the polarizability depression of 0.17 ų was found for He@Me₈Si₈O₁₂. In order to avoid the false conclusion about molecular symmetry the calculations of the structure of silsesquioxanes must be performed with sufficiently high accuracy (Int = ultrafine and Opt = tight in the use of the GAUSSIAN program).     

Normal coordinate analysis of H8Si8O12

Normal coordinate analysis of the fundamental vibrations of H₈Si₈O₁₂ has been carried out. Because of the octahedral symmetry, the 78 vibrational degrees of freedom lead to 33 different vibrations, six of which are infrared active, 13 are Raman active and 14 are inactive. From the internal coordinates one gets 116 symmetry coordinates. We describe a straightforward method for determining the internal symmetry coordinates of any molecular system. Internal coordinates, symmetry force constants, the full set of orthonormal symmetry coordinates as well as the 38 redundant orthonormal symmetry coordinates of H₈Si₈O₁₂ are tabulated. The potential energy distribution analysis shows that most of the fundamental vibrations can be very well interpreted in terms of the internal vibrations ν(SiH), ν(SiO), δ(SiH), δ(OSiO) and δ(SiOSi) which makes it easy to compare them with vibrations observed in other silsesquioxanes and similar silicon compounds.     

A quantum chemical study of the structure of dodecasilsequioxane H12Si12O18

Quantum chemical B3LYP/cc-pVTZ, PBE0/cc-pVTZ, and MP2(full)/6-311G(d,p) methods are used to calculate the structural parameters of dodecasilsequioxane H₁₂Si₁₂O₁₈ and the H₁₂Si₁₂O ₁₈ ⁺ cation. According to DFT/cc-pVTZ calculations the energy of H₁₂Si₁₂O₁₈ (D _6h ) is 1.3–1.7 kcal/mol higher than the energy of H₁₂Si₁₂O₁₈ (D _2d ). A reduction of the basis set results in a greater energy difference of H₁₂Si₁₂O₁₈ isomers. For the cation ² B _2u and ² B ₁ electronic states are obtained, which correspond to symmetric equilibrium structures H₁₂Si₁₂O ₁₈ ⁺ (D _6h ) and (D ₂) respectively. For the He@H₁₂Si₁₂O₁₈ endocomplex the D _2d symmetry is obtained; for He₂@H₁₂Si₁₂O₁₈ the D _2h symmetry; and for H₂@H₁₂Si₁₂O₁₈ the D _6h symmetry.     

Why is the Si-X stretching frequency of X8Si8O12 (X = H,CH3, Cl) much higher than that of XSi(OSiME3)3?

The totally symmetric stretching frequencies u₅(Si-X) of the octasilases-quioxanes X₈Si₈O₁₂ are distinctively larger than those of XSi(OSiMe₃)₃ for X = H, CH₃, Cl whereas u₅(Si-H) of H₈Si₈O₁₂ and of H₁₀Si₁₀O₁₅ differ very little. Inspection of the experimental data and molecular orbital calculations of the EHMO-ASED type show that this striking discrepancy is caused by the differences in the X-Si-O-Si conformations. The cage structure of X₂Si₈O₁₂ requires the anti X-Si-O-Si conformation whereas the syn conformation is the stable one in XSi(OSiMe₃)₃. The Si-H bond order decreases from anti to syn caused by a decreasing interaction of the H-ls orbital with the Si-O-pπ type orbitals.     

Silsesquioxane chemistry, 14.[1] A highly crowded disiloxane: Synthesis and structure of the bis(silsesquioxanyl) ether (Cy7Si8O12)2O

The bis(silsesquioxanyl) ether derivative (Cy₇Si₈O₁₂)₂O (4, Cy =c-C₆H₁₁) has been prepared for the first time by controlled hydrolysis of Cy₇Si₈O₁₂Cl (2) in the presence of triethylamine and structurally characterized by X-ray diffraction.     

Spectroscopically tracing the reactions of octahydridosilsesquioxane (H8Si8O12) with organic molecules

This article studies the reactions and mechanisms of H₈Si₈O₁₂ (T₈H₈) molecules with n-propanol, acetone, allyl alcohol, n-butylamine, allylamine, acetic acid, and 1-octene in air, at room temperature, and without catalysts. The reaction between T₈H₈ and n-propanol involves both the highly polarized Si O and Si H bonds and results in cage breakage and forming Q⁴ and Q³ structures with  OC₃H₇ in the reaction product. T₈H₈ also reacts with acetone, and the resultant product possesses Si OCH(CH₃)₂. Allyl alcohol is less reactive to cause T₈H₈ decomposition, and the resultant product contains Si OCH₂CHCH₂ and Si OCH₂(CH₂)₃CHCH₂. However, it is found that basically T₈H₈ does not react with acetic acid and 1-octene. In the reactions of T₈H₈ with n-butylamine and allylamine, the resultant products contain Si NH(CH₂)₃CH₃ and Si NHCH₂CHCH₂, respectively. For the reaction with T₈H₈, allylamine is less active than n-butylamine. Possible mechanisms for the T₈H₈ reactions are discussed.     

[TMPA]4[Si8O20] · 34 H2O and [DDBO]4[Si8O20] · 32 H2O are heteronetwork clathrates with 1,1,4,4-tetramethylpiperazinium (TMPA) and 1,4-dimethyl-1,4-diazoniabicyclo[2.2.2]octane (DDBO) guest cations

[TMPA]₄[Si₈O₂₀] · 34 H₂O ( 1 ) and [DDBO]₄[Si₈O₂₀] · 32 H₂O ( 2 ) have been prepared by crystallization from aqueous solutions of the respective quaternary alkylammonium hydroxide and SiO₂. The crystal structures have been determined by single-crystal X-ray diffraction. 1 : Monoclinic, a = 16.056(2), b = 22.086(6), c = 22.701(2) Å, β = 90.57(1)° (T = 210 K), space group C2/c, Z = 4. 2 : Monoclinic, a = 14.828(9), b = 20.201(7), c = 15.519(5) Å, β = 124.13(4)° (T = 255 K), space group P2₁/c, Z = 2. The polyhydrates are structurally related host-guest compounds with three-dimensional host frameworks composed of oligomeric [Si₈O₂₀]^8? anions and H₂O molecules which are linked via hydrogen bonds. The silicate anions possess a cube-shaped double four-ring structure and a characteristic local environment formed by 24 H₂O molecules and six cations (TMPA, [C₈H₂₀N₂]²⁺, or DDBO, [C₈H₁₈N₂]²⁺). The cations themselves reside as guest species in large, irregular, cage-like voids. Studies employing ²⁹Si NMR spectroscopy and the trimethylsilylation method have revealed that the saturated aqueous solutions of 1 and 2 contain high proportions of double four-ring silicate anions. Such anions are also abundant species in the saturated solution of the heteronetwork clathrate [DMPI]₆[Si₈O₁₈(OH)₂] · 48.5 H₂O ( 3 ) with 1,1-dimethylpiperidinium (DMPI, [C₇H₁₆N]⁺) guest cations.     

Darstellung und Kristallstruktur der Verbindung Li4H2Si2O7

Zusammenfassung Die Verbindung Li₄H₂Si₂O₇ wird durch Umsetzung von Li₆Si₂O₇ mit Methanol bzw. Wasserdampf dargestellt und ihre Kristallstruktur an Hand von Einkristallaufnahmen bestimmt. Die tetragonale Elementarzelle ( ) mita=7,59₅ undc=5,06 Å enthält zwei Formeleinheiten. Die Verbindung zählt zu den Sorosilicaten, mit [Si₂O₇]-Gruppen, die gleich angeordnet sind wie in Li₆Si₂O₇. Im Gegensatz zu Li₆Si₂O₇, das die Lithiumatome teils in einer vierzähligen Lage (KZ=5) teils einer achtzähligen Lage (KZ=4) enthält, ist in der Verbindung Li₄H₂Si₂O₇ nur letztere Position mit Lithiumatonen besetzt. Die Verteilung der Wasserstoffatome wird diskutiert.

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Preparation and crystal structure of the compoundLi ₄H₂Si₂O₇

The compound Li₄H₂Si₂O₇ has been prepared by reaction of Li₆Si₂O₇ with methanol and water vapour, resp. The crystal structure has been determined by single-crystal data. The tetragonal cell ( ):a=7.59₅ andc=5.06 Å contains two formula units. The compound belongs to the soro-silicates the [Si₂O₇]-groups being arranged analogous to Li₆Si₂O₇. In contrast to Li₆Si₂O₇, containing the lithium atoms both in a 4-fold position (c.n.=5) and an 8-fold position (c.n.=4), in the compound Li₄H₂Si₂O₇ only the latter is occupied by lithium atoms. The distribution of the hydrogen atoms is discussed.

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Erstmaliger Einbau eines späten Übergangsmetalls in ein Silsesquioxan‐Gerüst: Synthese und strukturelle Charakterisierung von Cy7Si7O12Fe(tmeda)

Silsesquioxane Chemistry. VIII First Incorporation of a Late Transition Metal into a Silsesquioxane Cage: Synthesis and Structural Characterization of Cy₇Si₇O₁₂Fe(tmeda) Cy₇Si₇O₁₂Fe(tmeda) ( 3 , Cy = cyclohexyl, tmeda = N,N,N′,N′‐tetramethylethylenediamine) has been prepared by reacting in situ generated Cy₇Si₇O₉(OLi)₃ ( 2 ) with anhydrous FeCl₃ followed by treatment with tmeda. Pale yellow crystalline 3 represents the first example of a metallasilsesquioxane in which a late transition metal is incorporated into a silsesquioxane cage. The compound crystallizes as discrete monomers in which the coordination sphere around Fe is saturated by addition of a chelating tmeda ligand ( 3 : monoclinic space group Cc, Z = 4, lattice dimensions at –100 °C: a = 2469.0(2), b = 1529.9(2), c = 1010.4(2) pm, β = 116.68(1)°, R = 0.052).     

Synthesis, characterization and studies on the third-order optical non-linearities of novel charge-transfer heteropoly complexes (C8H12N2)5H7PMo12O40 and (C8H12N2)3H3PMo12O40·5H2O

Summary Two novel charge-transfer (CT) heteropoly complexes, (C₈H₁₂N₂)₅H₇PMo₁₂O₄₀ (1) and (C₈H₁₂N₂)₃H₃-PMo₁₂O₄₀·5H₂O (2), prepared by reacting p-Me₂NC₆H₄NH₂ with the four-electron heteropoly blue H₇PMo₁₂O₄₀·12H₂O and heteropoly acid H₃PMo₁₂O₄₀· xH₂O, respectively, were characterized by elemental analysis, and u.v., i.r., XPS and e.s.r. spectroscopies. A sizable electron-transfer interaction occurs within the product molecules and the heteropoly anions retain their Keggin structure. Their third-order optical non-linearity coefficients were measured using the Z-scan technique at a concentration of 4.68 × 10⁻⁶ mol dm⁻³ for (1) and 2.79 × 10⁻⁶ mol dm⁻³ for (2), with I ₀ = 2.38 × 10¹³ w m⁻² and λ = 532nm. The |χ⁽³⁾| for (1) is 2.61 × 10⁻¹⁰ esu and |χ⁽³⁾| for (2) is 1.05 × 10⁻¹⁰ esu.     

Selective Hydrosilylation of Alkynes with Octaspherosilicate (HSiMe2O)8Si8O12

Comprehensive studies on platinum‐catalyzed hydrosilylation of a wide range of terminal and internal alkynes with spherosilicate (HSiMe₂O)₈Si₈O₁₂ ( 1 a ) were performed. The influence of the reaction parameters and the types of reagents and catalysts on the efficiency of the process, which enabled the creation of a versatile and selective method to synthesize olefin octafunctionalized octaspherosilicates, was studied in detail. Within this work, twenty novel 1,2‐(E)‐disubstituted and 1,1,2‐(E)‐trisubstituted alkenyl‐octaspherosilicates ( 3 a – m , 6 n – t ) were selectively obtained with high yields, and fully characterized (¹H, ¹³C, ²⁹Si NMR, FTIR, MALDI TOF or TOF MS ES⁺ analysis). Moreover, the molecular structure of the compound (Me₃Si(H)C=C(H)SiMe₂O)₈Si₈O₁₂ ( 3 a ) was determined by X‐ray crystallography for the first time. The developed procedures are the first that allow selective hydrosilylation of terminal silyl, germyl, aryl, and alkyl alkynes with 1 a , as well as the direct introduction of sixteen functional groups into the 1 a structure by the hydrosilylation of internal alkynes. This method constituted a powerful tool for the synthesis of hyperbranched compounds with a Si?O based cubic core. The resulting products, owing to their unique structure and physicochemical properties, are considered novel, multifunctional, hybrid, and nanometric building blocks, intended for the synthesis of star‐shaped molecules or macromolecules, as well as nanofillers and polymer modifiers. In the presented syntheses, commercially available reagents and catalysts were used, so these methods can be easily repeated, rapidly scaled up, and widely applied.     

Darstellung und Kristallstruktur von Cs8P8O24 · 8H2O

Synthesis and Crystal Structure of Cs₈P₈O₂₄ · 8H₂O Cs₈P₈O₂₄ · 8H₂O was obtained from Na₈P₈O₂₄ · 6H₂O by cation exchange. Crystal growth was achieved by applying gel techniques (agar agar). The crystal structure (P1 ; a = 766.6(8); b = 1 156.9(9); c = 1 163.4(9) pm; α = 100,2(1)°; β = 106.5(2)°; γ = 92.2(1)°; Z = 1; 4 099 unique diffractometer data; R = 0.051; R(w) = 0.037) contains cyclo-octaphosphate anions with point symmetry C_2h. The cesium atoms are coordinated irregularily by eight and ten oxygen atoms, respectively. The threedimensional linkage of the P₈O₂₄^8?-rings is established via bonds to cesium atoms and hydrogen bonds Provided by H₂O molecules.     

Silicon buckyballs versus prismanes: Influence of spatial confinement on the structural properties and optical spectra of the Si18H12 and Si19H12 clusters

The genetic algorithm is combined with the density functional theory to predict how the cylindrical spatial confinement affects the structural characteristics and optical adsorption spectra of the low‐energy Si₁₈H₁₂ and Si₁₉H₁₂ isomers. Retrieved ground states (minimum energy states) of Si₁₈H₁₂ and Si₁₉H₁₂ isomers significantly differ from the earlier proposed “ultrastable” aromatic molecular systems and prismanes. According to our calculations, they are represented by the almost spherical endohedral buckyballs. In contrast to pure silicic clusters (Si₁₈ or Si₁₉), the most of Si atoms in the low‐energy Si₁₈H₁₂ and Si₁₉H₁₂ are four‐coordinated. Spatial confinement results in more oblong structures with the different optical spectra. Prismanes under confinement get some energy advantages over the spherical structures, but despite this they do not become the most energetically favorable ones. Thus, the current results warrant however further research on the spatial confinement of silicic prismanes, as our study suggests challenges in devising the method of their synthesis without additional chemical techniques.     

Comparison of two polymeric transition metal complexes with 1,4‐benzenedicarboxylate ions as bridging ligands, [Co(C8H4O4)(C12H8N2)(H2O)] and [Cu(C8H4O4)(C10H9N3)]·H2O

The title complexes, catena‐poly[[aqua(1,10‐phenanthroline‐κ²N,N′)­cobalt(II)]‐μ‐benzene‐1,4‐di­carboxyl­ato‐κ²O¹:O⁴], [Co(C₈H₄O₄)(C₁₂H₈N₂)(H₂O)], (I), and catena‐poly[[[(di‐2‐pyridyl‐κN‐amine)copper(II)]‐μ‐benzene‐1,4‐di­carboxyl­ato‐κ⁴O¹,O^1′:O⁴,O^4′] hydrate], [Cu(C₈H₄O₄)(C₁₀H₉N₃)]·H₂O, (II), take the form of zigzag chains, with the 1,4‐benzene­di­carboxyl­ate ion acting as an amphimonodentate ligand in (I) and a bis‐bidentate ligand in (II). The Co^II ion in (I) is five‐coordinate and has a distorted trigonal–bipyramidal geometry. The Cu^II ion in (II) is in a very distorted octahedral 4+2 environment, with the octahedron elongated along the trans O—Cu—O bonds and with a trans O—Cu—O angle of only 137.22 (8)°.     

Synthesis and molecular structure of a tetrameric neodymium-silsesquioxane cage complex: {[(i-C4H9)7(Si7O12) Nd]4NaCl}

A new tetrameric neodymium-silsesquioxane cage complex {[(i-C₄H₉)₇(Si₇O₁₂)Nd]₄NaCl} (1) was prepared by the reaction of NdCl₃ with i-PrONa, and subsequent treatment with trisilanol [(i-C₄H₉)₇(Si₇O₉)(OH)₃] in toluene. The molecular structure of the complex was determined by single crystal X-ray diffraction. Preliminary study shows that complex 1 is active for highly cis-1,4 polymerization of isoprene (92% selectivity) in the presence of AlEt₃ and Me₃SiCl.     

Dodekahydro‐closo‐dodekaborate der schweren Erdalkalimetalle aus wäßriger Lösung: Ca(H2O)7[B12H12] · H2O,Sr(H2O)8[B12H12] und Ba(H2O)6[B12H12]

Dodecahydro‐ closo ‐dodecaborates of the Heavy Alkaline‐Earth Metals from Aqueous Solution: Ca(H₂O)₇[B₁₂H₁₂] · H₂O, Sr(H₂O)₈[B₁₂H₁₂], and Ba(H₂O)₆[B₁₂H₁₂] The crystalline hydrates of the heavy alkaline earth metal dodecahydro‐closo‐dodecaborates (M[B₁₂H₁₂] · n H₂O, n = 6–8; M = Ca, Sr, Ba) are easily accessible by reaction of an aqueous (H₃O)₂[B₁₂H₁₂] solution with an alkaline earth metal carbonate (MCO₃). By isothermic evaporation of the respective aqueous solution we obtained colourless single crystals which are characterized by X‐ray diffraction at room temperature. The three compounds Ca(H₂O)₇[B₁₂H₁₂] · H₂O (orthorhombic, P2₁2₁2₁; a = 1161.19(7), b = 1229.63(8), c = 1232.24(8) pm; Z = 4), Sr(H₂O)₈[B₁₂H₁₂] (trigonal, R3; a = 1012.71(6), c = 1462.94(9) pm; Z = 3) and Ba(H₂O)₆[B₁₂H₁₂] (orthorhombic, Cmcm; a = 1189.26(7) pm, b = 919.23(5) pm, c = 1403.54(9) pm; Z = 4) are neither formula‐equal nor isostructural. The structure of Sr(H₂O)₈[B₁₂H₁₂] is best described as a NaCl‐type arrangement, Ba(H₂O)₆[B₁₂H₁₂] rather forms a layer‐like and Ca(H₂O)₇[B₁₂H₁₂] · H₂O a channel‐like structure. In first sphere the alkaline earth metal cations Ca²⁺ and Sr²⁺ are coordinated by just seven and eight oxygen atoms from the surrounding water molecules, respectively. A direct coordinative influence of the quasi‐icosahedral [B₁₂H₁₂]^2– cluster anions becomes noticeable only for the Ba²⁺ cations (CN = 12) in Ba(H₂O)₆[B₁₂H₁₂]. The dehydratation of the alkaline earth metal dodecahydro‐closo‐dodecaborate hydrates has been shown to take place in several steps. Thermal treatment leads to the anhydrous compounds Ca[B₁₂H₁₂], Sr[B₁₂H₁₂] and Ba[B₁₂H₁₂] at 224, 164 and 116 °C, respectively.     

Thermal Methane Activation by [Si2O5].+ and [Si2O5H2].+: Reactivity Enhancement by Hydrogenation

The thermal reactions of methane with the oxygen‐rich cluster cations [Si₂O₅]^?+ and [Si₂O₅H₂]^?+ have been examined using Fourier transform–ion cyclotron resonance (FT‐ICR) mass spectrometry in conjunction with state‐of‐the‐art quantum chemical calculations. In contrast to the inertness of [Si₂O₅]^.+ towards methane, the hydrogenated cluster [Si₂O₅H₂]^.+ brings about hydrogen‐atom transfer (HAT) from methane with an efficiency of 28 % relative to the collision rate. The mechanisms of this process have been investigated in detail and the reasons for the striking reactivity difference of the two cluster ions have been revealed.     

Syntheses and crystal structures of [Na(H2O)](C17H13O6SO3)* 2H2O and [NKH2O)6]C17H13O6SO3)2*H2O

Two hydrates of sodium 5,7‐dihydroxy‐6,4′‐dimethoxyisoflavone‐3′‐sulfonate ([Na(H₂O)J(C₁₇H₁₃O₆SO₃)*2H₂O,] 1) and nickel 5,7‐dihydroxy‐6,4′‐dimethoxyisoflavone‐3′‐sulfonate ([Ni(H₂O)₆](C₁₇H₁₃O₆SO₃)₂*4H₂O, 2) were synthesized and characterized by IR, 'H NMR and X‐ray diffraction analyses. The hydrate 1 crystallizes in the mono‐clinic system, space group P2(1) with a=0.8201(9) nm, b=0.8030(8) nm, c= 1.5361(16) nm, β=102.052(12)°, V =0.9893(18) nm³, D,= 1.579 g/cm³, Z=2, μ=0.252 nm^?1, F(000)=488, R=0.0353, wR=0.0873. The hydrate 2 belongs to triclinic system, space group P‐1 with a=0.7411(3) nm, b=0.8333(3) nm, c=1.7448(7) nm, α= 86.361(6)°, β=86.389(5)°, γ= 88.999(3)°, V=1.0731(7) nm³, D,=1.587 g/cm³, Z=1, μ=0.649 m^?1, F(000)= 534. In the structure of 1, the sodium cation is coordinated by six oxygen atom and two adjacent ones are bridged by three oxygen atoms to form an octahedron chain. The C? H…?… hydrogen bonds exist between two isoflavone molecules in the structure of 2. Meanwhile, hydrogen bonds in two compounds, link themselves to assemble two three‐dimensional network structures, respectively.     

Nanoscale Control of Polyoxometalate Assembly: A {Mn8W4} Cluster within a {W36Si4Mn10} Cluster Showing a New Type of Isomerism

Two near isomeric clusters containing a novel {Mn₈W₄} Keggin cluster within a [W₃₆Mn₁₀Si₄O₁₃₆(OH)₄(H₂O)8]^24? cluster are reported: K₁₀Li₁₄ [W₃₆Si₄O₁₃₆Mn^II₁₀(OH)₄(H₂O)₈] ( 1 ) and K₁₀Li1_3.5Mn_0.25[W₃₆Si₄O₁₃₆Mn^II₁₀(OH)₄(H₂O)₈] ( 1′ ). Bulk characterization of the clusters has been carried out by single crystal X‐ray structure analysis, ICP‐MS, TGA, ESI‐MS, CV and SQUID‐magnetometer analysis. X‐ray analysis revealed that 1′ has eight positions within the central Keggin core that were disordered W/Mn whereas 1 contained no such disorder. This subtle difference is due to a differences is how the two clusters assemble and recrystallize from the same mother liquor and represents a new type of isomerism. The rapid recrystallization process was captured via digital microscopy and this uncovered two “intermediate” types of crystal which formed temporarily and provided nucleation sites for the final clusters to assemble. The intermediates were investigated by single crystal X‐ray analysis and revealed to be novel clusters K₄Li₂₂[W₃₆Si₄Mn₇O₁₃₆(H₂O)₈]?56 H₂O ( 2 ) and Mn₂K₈Li₁₄[W₃₆Si₄Mn₇O₁₃₆(H₂O)₈]?45 H₂O ( 3 ). The intermediate clusters contained different yet related building blocks to the final clusters which allowed for the postulation of a mechanism of assembly. This demonstrates a rare example where the use X‐ray crystallography directly facilitated understanding the means by which a POM assembled.