Synthesis and Spectroscopic Characterization of Organothiophosphoryl Polyoxotungstates α- [C6H11P (S) ]2Xn+W11O39(8-n)- (Xn+ = P5+, Si4+, Ge4+, Ga3+)

Organothiophosphoryl polyoxotungstate derivatives α-C6H11P(S)]2Xn W11O39(8-n)- (X=P, Si, Ge, Ga)were obtained by the reactions of the monovacant α-[Xn W11O39](12-n)- (X=P, Si, Ge, Ga) anions with electrophilic C6H11P(S)Cl2 in acetonitrile. These new organic-inorganic hybrid anions were characterized by elemental analyses, IR, 31P and 183W NMR spectrometries. The six-line 183W NMR spectrum indicates that [C6H11P (S) ]2Xn W11O39(8-n)- (X= P, Si, Ge, Ga) anions possess true Cs symmetry in acetonitrile. According to the spectroscopic observation and the chemical analyses, it is known that each of the hybrid anions consists of an α-[XW11O3)] framework on which two equivalent C6H11P(S) groups are grafted through P-O-W bridges.     

一缺位杂多阴离子XW11O(12-n)-39(X=P5+,Si4+,B3+,Ga3+)含硫有机膦衍生物的合成及结构表征

杂多化合物的衍生物由于具有潜在的多功能催化性能,长期以来一直受到人们的关注[1～3].将有机或有机金属基团引入杂多化合物中以修饰杂多阴离子的部分外部骨架结构,对研究杂多化合物的性质和应用及新型催化剂的开发具有重要意义[4,5].在杂多化合物表面引入适当的有机基团还可改善其溶解性能及其它物理性质,从而拓宽其应用范围.研究结果表明,这类化合物还具有很好的抗病毒和抗肿瘤活性[6,7].Klemperer等[8]合成的[(η5-C5H5)TiPW11O39]4-将多酸与金属有机化合物有机地融为一体,从而开辟了多酸金属有机化学的新领域.此后,相继合成了许多多酸型金属有机化合物[9],然而缺位杂多阴离子的有机膦衍生物的研究却鲜见报道[10].     

Divacant polyoxotungstates: reactivity of the gamma-decatungstates [γ-XW10O36]8-(X = Si, Ge)

The dilacunary, Keggin-based gamma-decatungstate ions [γ-XW(10)O(36)](8-) (X = Si, Ge) {XW(10)} exhibit an exciting and versatile solution chemistry, which is probably unmatched by any other lacunary polytungstate. The reactivity of {XW(10)} in the presence, and even absence, of electrophiles, includes loss/gain of tungsten, isomerization, and dimerization. Ever since the syntheses and structures of {XW(10)} were reported, many research groups around the world have investigated the reactivity of these polyanions towards nucleophiles (mostly d-block metal ions) and different products with various shape, size and composition were obtained. Here we provide an overview of the state-of-the-art in this subarea of polyoxometalate chemistry, with a focus on synthetic and structural aspects.     

Synthesis and chemical behavior of the inorganic cryptates (MSb9W21O86)(19−n)− Mn+  Na+, K+, NH4+, Ca2+, Sr2+

The synthesis and the chemical behavior of the polyanionic ligand Sb₉W₂₁O₈₆¹⁹⁻ were studied: two types of coordination sites were evidenced and their reactivity discussed with regard to the polytungstic structure.     

Synthesis,spectroscopic properties and crystal structure of organophosphoryl polyoxotungstate α-[Bu4N]3H[PhCH2P(O)]2SiW11O39

Reaction of the monovacant heteropolyanions α-[SiW₁₁O₃₉]^8? with PhCH₂PO(OH)₂ leads to the formation of the organophosphoryl derivative α-[Bu₄N]₃H[PhCH₂P(O)]₂SiW₁₁O₃₉ (1). Single-crystal X-ray diffraction analysis shows that the crystal is monoclinic with space group P2₁ /n and the unit cell parameters: a?=?14.386 (3)?Å, b?=?27.015 (5)?Å, c?=?25.480 (5)?Å, α?=?90°, β?=?91.44 (3)°, γ?=?90°, V?=?9899 (3)?ų. Z?=?4, D _c?=?2.467?g?cm^?1, λ (Mo-Kα)?=?0.071073?nm, R ₁?=?0.0638, wR ₂?=?0.1364. The hybrid anion consists of an α-[SiW₁₁O₃₉]^8? framework on which two equivalent organophosphoryl groups are grafted through P?O?W bridges; each of the two PhCH₂P(O) groups are connected to two terminal oxygen atoms belonging to a triad and a diad, respectively.     

Organophosphoryl polyoxotungstates α-[R2PW9O34]5− [R = PhP(S), C6H11P(O), H2NCH(n-Pr)P(O)]

Tetrabutylammonium salts of organophosphoryl derivatives of tungstophosphate of formula α-[R₂PW₉O₃₄]⁵⁻ [R = PhP(S), C₆H₁₁P(O), H₂NCH(n-Pr)P(O)] have been prepared, purified and characterized by elemental analysis, i.r., ³¹P- and ¹⁸³W-n.m.r. spectroscopy. These anions consist of an α-[PW₉O₃₄]⁹⁻ framework on to which are grafted two equivalent organophosphoryl groups through P–O–W bridges; these new species still retain the ‘unsaturated’ Keggin structure. The five-line ¹⁸³W spectra indicates that the hybrid anions possess C _s symmetry in acetonitrile. This revised version was published online in June 2006 with corrections to the Cover Date.     

Synthesis,Electronic Properties and Reactivity of [B12X11(NO2)]2− (X=F–I) Dianions

Nitro-functionalized undecahalogenated closo-dodecaborates [B₁₂X₁₁(NO₂)]²⁻ were synthesized in high purities and characterized by NMR, IR, and Raman spectroscopy, single crystal X-diffraction, mass spectrometry, and gas-phase ion vibrational spectroscopy. The NO₂ substituent leads to an enhanced electronic and electrochemical stability compared to the parent perhalogenated [B₁₂X₁₂]²⁻ (X=F–I) dianions evidenced by photoelectron spectroscopy, cyclic voltammetry, and quantum-chemical calculations. The stabilizing effect decreases from X=F to X=I. Thermogravimetric measurements of the salts indicate the loss of the nitric oxide radical (NO^.). The homolytic NO^. elimination from the dianion under very soft collisional excitation in gas-phase ion experiments results in the formation of the radical [B₁₂X₁₁O]^2−.. Theoretical investigations suggest that the loss of NO^. proceeds via the rearrangement product [B₁₂X₁₁(ONO)]²⁻. The O-bonded nitrosooxy structure is thermodynamically more stable than the N-bonded nitro structure and its formation by radical recombination of [B₁₂X₁₁O]^2−. and NO^. is demonstrated.     

Determination of the protonation state of [H3PW11O39]4− and the stability constant of [Ag(H2O)(H3PW11O39)]3− in aqueous solution

By employing elemental analysis, ³¹P NMR, pH, and conductivity measurements, the protonated state of lacunary heteropolyoxotungstophosphates in aqueous solution, {PW₁₁O₃₉}, is determined to be [H₃PW₁₁O₃₉]^4?. Using it as ligand, a complex of [Ag(H₂O)(H₃PW₁₁O₃₉)]^3? is formed. An electrochemical cell is designed as follows: (?) Hg, Hg₂Cl₂ [Ag(H₂O)(H₃PW₁₁O₃₉)]^3? (aq) | Ag(s) (+) (salt bridge is saturated KNO₃ solution). By measuring the electromotive force of the cell, the stability constant of [Ag(H₂O)(H₃PW₁₁O₃₉)]^3? in aqueous solution is determined to be 4.34 × 10³ (25 °C).     

Quantum chemical study of redox-switchable second-order optical nonlinearity in Keggin-type organoimido derivative [PW11O39(ReNC6H5)] n− (n = 2–4)

To analyze the effect of redox state changes on the second-order nonlinear optical (NLO) responses of organoimido-functionalized Keggin-type heteropolyanions, the excitation properties and static second-order polarizabilities of fully oxidized state, the first and second reduced states were calculated by means of the time-dependent density functional theory (TDDFT) method combined with the sum-over-states (SOS) formalism. The incorporation of extra electrons causes significant enhancement in the second-order NLO activity. The reduced complexes show more than three times the efficiency of fully oxidized state. Moreover, the NLO activities for PW₁₁Re^VNPh system can also be modified by controlling the spin multiplicity. The high spin state (³ 3) has twice larger β _vec value than the low spin state (¹ 3). The characteristic of the charge-transfer transition corresponding to the dominant contributions to the β _vec values indicates that metal-centered redox processes influence the intramolecular donor or acceptor character, which accordingly leads to the variations in the computed β values. Owing to the reversible and manipulable redox processes, these kinds of the POM-based hybrid complexes could comprise a promising family of three-state redox-switchable molecular device combining chromic, magnetic, and NLO output.     

Diverse Reactivity of bis(Silylene) and bis(Germylene) [LE−EL (E=Si and Ge: L=PhC(NtBu)2)] in the Oxidative Activation of C−F Bond: Si−Si Bond is Retained While the Ge−Ge Bond Is Cleaved

Herein we report the reactions of 3,4,5,6-tetrafluoroterephthalonitrile ( 1 ) with bis(silylene) and bis(germylene) LE−EL [E=Si ( 2 ) and Ge( 3 ): L=PhC(N^tBu)₂)]. The reaction of LSi−SiL (L=PhC(N^tBu)₂) ( 2 ) with two equivalents of 1 resulted in an unprecedented oxidative addition of a C−F bond of 1 leading to disilicon(III) fluoride {L(4-C₈F₃N)FSi−SiF(4-C₈F₃N)L}( 4 ), wherein the Si−Si single bond was retained. In contrast, the reaction of LGe−GeL (L=PhC(N^tBu)₂) ( 3 ) with one equivalent of 1 resulted in the oxidative cleavage of Ge−Ge bond leading to L(4-C₈F₃N₂)Ge ( 5 ) and LGeF ( 6 ). All three compounds ( 4 – 6 ) were characterized by NMR spectroscopy, EI-MS spectrometry, and elemental analysis. X-ray single-crystal structure determination of compound 4 unequivocally established that the Si^III−Si^III bond remains uncleaved.     

The Oxalato-Titanium-Containing Tungstophosphate(V) Dimers, [Ti8(C2O4)8P2W18O76(H2O)4]18− and [Ti6(C2O4)4P4W32O124]20−

The oxalato-titanium(IV)-containing, dimeric 18-tungsto-2-phosphate [Ti₈(C₂O₄)₈P₂W₁₈O₇₆(H₂O)₄]^18? (1) and the 32-tungsto-4-phosphate [Ti₆(C₂O₄)₄P₄W₃₂O₁₂₄]^20? (2) are formed upon reaction of the oxalato-titanium complex [TiO(C₂O₄)₂]^2? with the trilacunary Keggin precursor [A-α-PW₉O₃₄]^9? and the hexalacunary Wells–Dawson precursor [H₂P₂W₁₂O₄₈]^12?, respectively. Polyanion 1 consists of two {PW₉} units encapsulating eight titanium centers and connected to each other via two Ti–O–Ti bridges, and crystallizes as a mixed potassium-sodium-lithium salt in the triclinic space group $P{\bar{1}}$ . Polyanion 2 comprises two {P₂W₁₆} units containing each two titanium atoms, and the two half-units are connected via two titanium atoms decorated by two oxalate groups each, and crystallizes as a mixed potassium-lithium salt in the rhombohedral space group $R{\bar{3}}c$ . Polyanions 1 and 2 were characterized in the solid state by single-crystal XRD, FT-IR, and TGA, whereas polyanion 2 was also investigated by ³¹P and ¹⁸³W NMR.     

Synthesis,characterization and properties of the α-K7[GaW11Ti(O2)O39]·11H2O heteropolyanion

The peroxotitanium-substituted heteropolytungstate -K₇[GaW₁₁Ti(O₂)O₃₉]·11H₂O has been prepared and characterized by elemental analysis, i.r., u.v., ¹⁸³W-n.m.r. and by electrochemistry. The ¹⁸³W-n.m.r. spectrum consists of six lines with intensity ratio 2:2:1:2:2:2, indicating that the TiO₂ occupies the empty octahedral site of the -K₉[GaW₁₁O₃₉]·xH₂O anion forming a polyanion with C _s symmetry. The characteristic charge-transfer absorption band O^2– ₂ Ti at 385 nm occurs in the u.v. spectrum. The polargraphic reduction potential of O^2– ₂ at ca. + 0.95 V has been determined.     

Synthesis and structure of bismuth complexes [Ph3MeP] 2 + [BiI3.5Br1.5(C5H5N)]2− · C5H5N, [Ph4Bi] 4 + [Bi4I16]4− · 2Me2C=O, and [Ph3(iso-Am)P] 4 + [Bi8I28]4− · 2Me2C=O

Complexes [Ph₃MeP] ₂ ⁺ [BiI_3.5Br_1.5(C₅H₅N)]^2? · C₅H₅N(I), [Ph₄Bi] ₄ ⁺ [Bi₄I₁₆]^4? · 2Me₂C=O (II), and [Ph₃(iso-Am)P] ₄ ⁺ [Bi₈I₂₈]^4? · 2Me₂C=O (III) were synthesized by reactions of bismuth iodide with triphenylmethylphosphonium bromide, triphenylbismuthonium sulfosalicylate, and triphenylisoamylphosphonium iodide, respectively. The crystal structures of complexes I–III were determined by X-ray crystallography. The complexes contain, in addition to cations and solvent molecules, mono-, tetra-, and octanuclear anions, in which bismuth atoms are in octahedral coordination.     

Dimerization of cobalt-substituted Keggin phosphotungstate, [PW11O39Co(X)]5−, in nonpolar solvents

The tetraheptylammonium (THA) salt of cobalt-substituted polyoxotungstate with Keggin-like structure, (THA)₅[PW₁₁O₃₉Co^II(X)], was investigated by ³¹P NMR and UV/VIS spectroscopies in toluene. A solution obtained after transferring PW₁₁Co from aqueous solution into toluene, using THABr as a transfer agent, and rigorous drying, gives multiple peaks in the ³¹P NMR spectrum. The spectrum in dry toluene significantly simplifies, after extracting a hexane solution several times with water, which removes simple inorganic ions. However, even the dry toluene solution after purification has ³¹P NMR and UV/VIS spectra which cannot be explained using the known equilibrium between (THA)₅[PW₁₁O₃₉Co(H₂O)] and (THA)₅[PW₁₁O₃₉Co(__)]. Both ³¹P NMR and UV/VIS spectroscopies indicate the existence of dimers in dry toluene solutions, (THA)₁₀[(PW₁₁O₃₉Co)₂]. Pure (THA)₅[PW₁₁O₃₉Co(_)] with five-coordinate cobalt can, however, be obtained in dry toluene in the presence of excess inert salt (high ionic strength conditions). Quantum mechanical/molecular mechanical calculations also support dimer formation in toluene.     

Synthesis and characterization of [PtMe3L(H2O)]BF4·H2O (L=3-O-acetyl-1,2-O-isopropylidene-α-D-glucofuranose)

Reaction of [PtMe₃(Me₂CO)₃]BF₄ (1) with 3-O-acetyl-1,2;5,6-di-O-isopropylidene--D-glucofuranose in acetone affords [PtMe₃L]BF₄ (2) (L=3-O-acetyl-1,2-O-isopropylidene--D-glucofuranose). In wet methylene chloride, complex2 transforms to [PtMe₃L(H₂O)]BF₄·H₂O (3). Complex3 was characterized by microanalysis and NMR spectroscopy (¹H,¹³C,¹⁹⁵Pt). The X-ray structure analysis (monoclinic, P2¹, a=10.529(3) , b=7.322(2) , c=14.668(4) , Z=2) reveals that 3-O-acetyl-1,2-O-isopropylidene--D-glucofuranose acts as a neutral bidentate ligand which is coordinated via two hydroxyl groups (²O^5,6 coordination). The five-membered 1,3,2-dioxaplatina rings exhibit an envelope conformation. The coordination sphere of platinum is completed by H₂O ligand.Institut für Anorganische Chemie, Martin-Luther-Universität; Halle-Wittenberg, Kurt-Mothes Str. 2, D-06120 Halle/Saale, Germany. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1119–1126, August, 1999.     

Synthesis and Structure of Two Keggin-Type Heteropolyanions: [VMo12O40]3n− n (1) and [H3PMoVMoVI 11O40]1− (2)

Two Keggin-type heteropolyanions were synthesized and characterized by X-ray crystal structure and elemental analysis as well as infrared spectroscopy. Both K₃[VMo₁₂O₄₀]19H₂O (1) and [N _i (H₂O)₆][H₃PMo^VMo^VI ₁₁O₄₀]₂30 H₂O (2) were prepared in aqueous solution. Compound 1 crystallized in the space group Pm-3m, a=10.6513(1) Å, V=1208.4(3) ų, Z=1. Compound 2 crystallized in the space group R-3 with a=b=13.9669(2) Å, c=42.0075(5) Å, V=7096.71(2) ų, Z=3. The compound 1 contains a {K₆VMo₁₂O₄₀} group in which six potassium ions form a regular {K₆} octahedron. The heteropolyanion [VMo₁₂O₄₀]^3– was capped by six potassium ions and enclosed by {K₆} octahedron. A three-dimensional structure was formed by the buildup of {K₃[VMo₁₂O₄₀]} _n . Compound 2 contains a one-electron reduced heteropolyanion [H₃PMo^VMo^VI ₁₁O₄₀]^1–. Ni²⁺ coordinated by six water molecules as the counter cation balances the negative charge of the molecule.     

Si4X(X=C,N,O,Si,P,S)原子簇结构的理论研究

在密度泛函B3LYP/6-311G*水平上, 对具有C3v对称的Si4X (X = C, N, O, P, S)原子簇进行了几何构型优化计算, 并讨论它们的热力学稳定性、动力学活性、Mulliken布居、SiX键长、占据价轨道的对称性以及HOMO能级位置等周期递变规律。     

Synthesis and characterization of α-[P2W15O62M3]12- (M = Ti or Zr) heteropolyanions

Summary The trisubstituted Dawson anions -XaHb[P₂W₁₅O₆₂M₃]· nH₂O (X = K or Me₄N; a + b = 12; M = Ti or Zr) have been prepared from the lacunary precursor Na₁₂[-P₂ W₁₅O₅₆]·24H₂O and characterized by elemental analysis, i.r., u.v. and ¹⁸³W-n.m.r. spectroscopy, and by an electrochemical method. The ¹⁸³W-n.m.r. spectrum of -[P₂W₁₅Ti₃O₆₂]^12– exhibits three lines of 122 intensity at –148.32, –182.91 and –212.95 p.p.m., as expected for the C _3v structure of the trisubstituted -Dawson anion.Author to whom all correspondence should be directed.