Crystal structures and solution properties of discrete complexes composed of saddle-distorted molybdenum(v)-dodecaphenylporphyrins and keggin-type heteropolyoxometalates linked by direct coordination

Reactions of a saddle-distorted Mo(V)-porphyrin complex, [Mo(DPP)(O)(H(2)O)]ClO(4) (1·ClO(4); DPP(2-) = dodecaphenylporphyrin dianion), with tetra-n-butylammonium (TBA) salts of Keggin-type heteropolyoxomatalates (POMs), α-[XW(12)O(40)](n-) (X = P, n = 3, 2; X = Si, n = 4, 3; X = B, n = 5; 4), in ethyl acetate/acetonitrile gave 2:1 complexes formulated as [{Mo(DPP)(O)}(2)(HPW(12)O(40))] (5), [{Mo(DPP)(O)}(2)(H(2)SiW(12)O(40))] (6), and [(n-butyl)(4)N](2)[{Mo(DPP)(O)}(2)(HBW(12)O(40))] (7) under mild reaction conditions. The crystal structures of the complexes were determined by X-ray crystallography. In these three complexes, named Porphyrin Hamburgers, the POM binds to two Mo(V) centers of porphyrin units directly via coordination of two terminal oxo groups. In spite of the similarity of those POM's structures, those Porphyrin Hamburgers exhibit different coordination bond angles between POM and the Mo(V) center in the porphyrin: 5 and 7 show two different coordination bond angles in one molecule in contrast to 6, which exhibits only one coordination bond angle. The Porphyrin Hamburgers involve protonation of the POM moieties to adjust the charge balance, as confirmed by spectroscopic titration with bases. In the crystals, the Porphyrin Hamburgers form two-dimensional (2D) sheets in the ac plane based on π-π interactions among peripheral phenyl substituents. Stacking of the 2D sheets toward the b axis constructs a 3D layered structure involving channels running into the crystallographic [1 0 0] and [0 0 1] directions in the crystal to include solvent molecules of crystallization for 5-7, and also counter cations for 7. Three complexes were revealed to be stable enough to maintain their structures even in solutions to show molecular ion peaks in the MALDI-TOF-MS measurements. They also exhibited different electron paramagnetic resonance (EPR) signals because of the Mo(V) (S = 1/2, I = 0) centers, reflecting the difference in the crystal structures. In addition, these complexes showed reversible multistep redox processes as observed in their cyclic voltammograms in benzonitrile to demonstrate high stability throughout the redox reactions in solution.     

Assembly of heterometallic clusters and coordination polymers by combining Mo-S-based clusters with Mn2+

Addition of [Mo(V)2O2S2(edt)2]2- (edt =1,2-ethanedithiolate) to acetonitrile and/or methanol solutions of MnII containing bipyridines [4,4'-trimethylenedipyridine (TDP), 4,4'-bipyridine (4,4'-bpy), 2,2'-bipyridine (2,2'-bpy)] or 15-crown-5 produces three new heterometallic cluster coordination polymers, [Mn2[Mo2O2S2(edt)2]2(TDP)3(CH3OH)2(NCMe)2].3CH3OH.0.25MeCN (1), [Mn(TDP)2(H2O)2]2+[Mn[Mo2O2S2(edt)2)2(TDP)2]]2-.6CH3OH (2), [Mn[Mo2O2S2(edt)2](TDP)2(CH3OH)(H2O)].CH3OH (3), and three new multinuclear clusters, [Mn[Mo2O2S2(edt)2](4,4'-bpy)(CH3OH)4].0.5(4,4'-bpy) (4), [Mn[Mo2O2S2(edt)2](2,2'-bpy)2].2CH3OH (5), and (NEt4)2[Mn(15-crown-5)[Mo2O2S2(edt)2]2] (6). All compounds were characterized by X-ray crystallography. The coordination mode of Mn in these compounds depends on the ligands and the crystallization conditions. Compound 2 readily converts to 1 or 3 depending on the reaction and solvent conditions. Compounds 1 and 2 were analyzed using thermogravimetric analysis combined with mass spectroscopy (TG-MS) in the temperature range 25-500 degrees C. The room-temperature magnetic moments for compounds 1-6 were determined.     

Shaping and enforcing coordination spheres: the implications of C3 and C1 chirality in the coordination chemistry of 1,1,1-tris(oxazolinyl)ethane ("trisox")

A key feature of tris(oxazolinyl)ethane ("trisox") ligands, which have shown broad scope in asymmetric catalysis, is the orientation and steric demand of their oxazoline substituents. This, along with the modularity of their synthesis determines their coordination chemistry. The possibility to combine oxazolines, in which the stereogenic centers adjacent to the N-donor atoms have different absolute configuration, whilst retaining their ability to coordinate as tripodal ligands, has been demonstrated by the synthesis of the enantiomerically pure C3-symmetric iPr-trisox(S,S,S) and C1-symmetric iPr-trisox(S,S,R) and their reaction with [Mo(CO)3(NCMe)3] yielding [Mo{iPr-trisox(S,S,S)}(CO)3] (1 a) and [Mo{iPr-trisox(S,S,R)}(CO)3] (1 b), respectively. The non-autocomplementarity of two homochiral trisox ligands at one metal center has been demonstrated by reaction of rac-C3 iPr-trisox with one equivalent of [Co(ClO4)2].6 H2O, giving the centrosymmetric heterochiral complex [Co(iPr-trisox)2](ClO4)2 (3), whereas an analogous reaction with the enantiopure ligand yielded a mixture of Co(II) complexes, which is characterized by the total absence of a [(trisox)2Co](+/2+) ion. The scope of the trisox ligand in terms of facial coordination to both early and late transition metals was demonstrated by the synthesis and structural characterization of the mononuclear complexes [ScCl3(iPr-trisox)] (4), [Fe(tBu-trisox)(NCMe)3](BF4)2 (5), and [Ru(eta6-p-cymene)(iPr-trisox)](PF6)2 (6). The facial coordination of their three ligating atoms to a metal center may be impeded if the transition-metal center stereoelectronically strongly favors a non-deltahedral coordination sphere, which is generally the case for the heavier d8-transition-metal atoms/ions. Reaction of iPr-trisox with [Rh(cod)2]BF4 led to the formation of the 16-electron d8-configured complex [Rh(iPr-trisox)(cod)](BF4) (7), which is oxidized by CsBr3 to give the Rh(III) complex [RhBr3(iPr-trisox)] (8) possessing a C3-symmetric structure with a kappa3-N-trisox ligand. The crystalline salts [M2(mu-Cl3)(iPr-trisox)2](PF6) (M=Fe(II): 9, Co(II): 10, Ni(II): 11), were prepared by addition of one molar equivalent of iPr-trisox and an excess of KPF6 to solutions of the anhydrous (FeCl2) or hydrated metal halides (CoCl2.6 H2O, NiCl2.6 H2O). All dinuclear complexes display weak magnetic coupling. For the mononuclear species [CuCl2(iPr-trisox)] (12) the removal of a chloride anion and thus the generation of a dinuclear chloro-bridged structure failed due to Jahn-Teller destabilization of a potential octahedral coordination sphere.     

Scandium(III) coordination polymers containing capsules based on two p-sulfonatocalix[4]arenes

Reactions of sodium p-sulfonatocalix[4]arene and scandium(III) tristriflate in the presence, and absence, of [18]crown-6 give the crystalline complexes [Sc2(mu-OH)2(H2O)10][Na4(H2O)8-[calix[4]arene(SO3)4]2).13 H2O and [[Sc2(mu-OH)2(H2O)8][Sc(H2O)4]2[calix[4]-arene(SO3)4-H+]2([18]crown-6).16H2O. Both complexes involve novel coordination polymers with calixarene units linked through sodium or scandium centers and also feature capsule assemblies through to the head-to-head association of calixarenes. A linear array of capsules associated with an infinite chain of aquo-bridged sodium ions, and an aquated hydroxy-bridged scandium(III) dimer, [Sc2(mu-OH)2(H2O)10]4+, are found in the absence of the crown ether. In the presence of [18]crown-6 both hydrated scandium monomers and dimers bridge between calixarenes in a two-dimensional coordination network. The crown ethers reside in cavities created by two calixarenes from adjacent polymeric sheets via a variety of supramolecular interactions(hydrogen-bonding, shape complementarity), and effectively add a third dimension to the network. The extended structure of both of these polymers is highly porous, and resembles a bilayer.     

A SERIES OF TRINUCLEAR MOLYBDENUM CLUSTERS WITH LOOSE COORDINATION SITES

<正> The cluster compound Mo3S4[S2P(OEt)2]4(H2O) with a comparatively stable cluster core [Mo3(μ3-S)(μ-S)3]4+ and some labile ligands or loosely coordination sites has been already prepared successfully by a self-assembly reaction. Its surprising chemical reactivity in the reactions of substitution, addition, and oxidation has been noted and used widely for the syntheses of a series of new, trinuclear Mo cluster compounds, of which the structures of the 12 selected compounds characterized by X-ray diffraction analysis are exhibited in diagrams. Meanwhile, those compounds with the same cluster core [Mo3(μ3-S)(μ-S)2]4+ show two groups of characteristic IR bands at ~480 cm-1 for the Mo-(μ-S) vibration and -450cm-1. for the Mo- (μ3-S), and their selected bond distances are tabulated as well.In a cluster-catalyzed homogeneous process, it is important that clusters have loose coordination sites or are coordination unsaturated. In our further research on the medium-valence molybdenum clusters[1], we have foun     

Aqueous solution chemistry of [Mo3CuSe4]n+ (n = 4, 5) and [W3CuQ4]5+ (Q = S, Se) clusters

The triangular cluster [Mo3Se4(H2O)9]4+ reacts with Cu turnings to give a new heterometallic cuboidal cluster [Mo3CuSe4(H2O)10]4+(purple; UV/Vis lambda(epsilon): 352(3907), 509(2613)). The reaction of [Mo3Se4(H2O)9]4+ with CuCl afforded the 5+ cube [Mo3CuSe4(H2O)10]5+(red; UV/Vis lambda(epsilon): 356(5406), 500(3477)). In contrast, [W3Se4(H2O)9]4+ both with Cu and CuCl gives the 5+ cube, [W3CuSe4(H2O)10]5+(yellow-green; UV/Vis lambda(epsilon): 312(5327), 419(3256) and 628(680)). Cyclic voltammetry of [M3CuQ4(H2O)10]5+ in 2 M HCl (M = Mo, W; Q = S, Se) shows a reversible one-electron reduction wave for the Mo clusters, but no reduction occurs for the W clusters prior to H+ reduction. In HCl solutions, Cl is coordinated to the Cu site of the clusters, alongside some less extensive coordination to Mo and W, and for [W3(CuCl)S4(H2O)6Cl3]+, isolated as the supramolecular adduct with cucurbit[6]uril, [W3(CuCl)S4(H2O)6Cl3]2Cl2 x C36H36N24O12 x 12H2O, the crystal structure was determined (Cu-W 2.856(4) angstroms, W-W 2.7432(15) angstroms, Cu-Cl 2.167(13) angstroms).     

Self-assembly of organic-inorganic hybrid materials constructed from eight-connected coordination polymer hosts with nanotube channels and polyoxometalate guests as templates

Two polyoxometalate-templated organic-inorganic hybrid porous frameworks, namely, [Cu2(H2O)2(bpp)2Cl][PM12O40].approximately 20H2O (for 1, M = W; for 2, M = Mo; bpp = 1,3-bis(4-pyridyl)propane), were self-assembly obtained and structurally determined by elemental analyses, inductively coupled plasma analyses, infrared spectroscopy, and single-crystal X-ray diffraction analyses. Single-crystal X-ray analysis of these crystals revealed that both of the structures are constructed from eight-connected three-dimensional coordination polymer hosts [Cu2(H2O)2(bpp)2Cl]n(3n+) and ball-shaped Keggin-type guests [PM12O40]n(3n-) as templates. The polymer hosts resulted from a bcc-type framework with nanotubes, and the nanotubes can be regarded as a tetra-stranded helix structure. Furthermore, compounds 1 and 2 exhibit photoluminescent properties at ambient temperature, and the compound 2 bulk-modified carbon paste electrode ( 2-CPE) displays good electrocatalytic activity toward the reduction of nitrite.     

Redistribution and fluxionality in heteropolyoxoperoxo complexes: [PO4[M2O2(mu-O2)2(O2)2]2]3- with M = Mo and/or W

When peroxotetramolybdophosphate, [(n-C4H9)4N]3[PO4[Mo2O2(mu-O2)2(O2)2]2], denoted (NBu4)3PMo4, and its tungsten(VI) analogue, (NBu4)3PW4, are mixed in acetonitrile at room temperature, redistribution occurs with the formation of three mixed-addenda species [PO4[Mo4-xWxO20]]3- (x = 1-3). The temperature dependence of the phosphorus-31 NMR spectra of a 1 1 mixture and of the pure salts, (NBu4)3PMo4 or (NBu4)3PW4, shows that [MO(O2)2] species are in chemical exchange, as are the [MOp] units of certain heteropolyacids (e.g. H3[PMo12O40] x aq and H3[PW12O40] x aq). However, there is no chemical exchange between free phosphate and [MO(O2)2] species in these systems; but there is fluxional behaviour involving PMo2W2, PMo4 and PW4. This is attributed to the rapid equilibrium between isomers (PMo2W2) and to equilibrium between anionic structures with tridentate (mu-eta2:eta1-O22-) and bidentate (eta2-O22-) modes of coordination for the two peroxo groups of the [M2O2(mu-O2)2(O2)2] moieties.     

钼簇合物反应性能的研究-SbCl3和具有松散配位三核钼簇合物的加合反应及其产物的晶体结构

报道具有松散配位的三核钼簇合物{Mo3(μ3-S)(μ-S)3[S2P(OEt)2]4.L(L'=H2O,C3H3ON,和SbCl3在HCl-EtOH中加合反应及其产物{Mo3(μ3-S)[(μ-S)3.SbCl3].[S2P(OEt)2]4(C2H5OH)}(C2H5OH)和{Mo3(μ3-S)[(μ-S)3.SbCl3][S2P(OEt)2]3[SXP(OEt)2].(C3H3ON)}(X=S,O)的晶体结构。结构测定结果表明,这两个加合物的分子由{Mo3(μ3-S)(μ-S)3[S2P(OEt)2]4.L(L=C2H5OH,C3H3ON)通过三个(μ-S)联结SbCl3而成,从而获得了{Mo3SbS4}的类立方烷簇胳构型,Sb一S之间存在较弱的配位键, 由此推断,若加合的金属原子的轨道和电子组态适宜,有可能通过这种[3+1]的成簇模式获得四核的同核或异核簇合物。     

三维超分子配合物[MoO_2(OCH_2C_5H_4N)_2]制备、晶体结构及三阶非线性光学性质

Na_2MoO_4·2H_2O和2-氯甲基吡啶在水中反应得到了超分子化合物：[MoO_2 (OCH_2C_5H_4N)_2]。其单晶结构测试表明：该化合物含有两种均为6配位的但化学 环境不同的Mo(1)和Mo(2)原子;由此两种钼原子构成的中性配合物[Mo(1)O_2 (OCH_2C_5H_4N_2)]和[Mo(2)O_2(OCH_2C_5H_4N)_2]分别通过氢键O…H-C及吡啶环 间的π-π堆积作用形成了二维的A层和B层,A层与B层之间又在层间氢键的作用下 交错形成了三维的网状固态结构。用Z-scan法在DMF溶液中测试了该化合物的三阶 非线性光学性能,发现它有强的非线性吸收(α_2 = 1.92 * 10~(-9) m·W~(-1)) ,非线性极化率X~((3)) = 1.21 * 10~(-12) esu。     

Hydrogen-bonded networks through second-sphere coordination

The reaction of 4, 7-phenanthroline (1) with aqueous transitionmetal complexes [Mn(H2O)6][NO3]2, [Co(H2O)6][NO3]2, [Ni(H2O)6[NO3]2, [Mn(H2O)6][ClO4]2, and [Co(H2O)6][ClO4]2 does not produce coordination complexes between these metal cations and the N-donor ligand as expected. Instead, supramolecular hydrogenbonded networks are formed between the nitrogen donor atoms of 4, 7-phenanthroline and the OH groups of coordinated water molecules: M-O-H...N interactions. This motif of second-sphere coordination for 1 can be exploited as a tool for crystal engineering. As a demonstration of the generality of this new interaction as a supramolecular building block, five X-ray crystal structures are reported that utilise this hydrogen bonding scheme; [Co(H2O)4(NO3)2].(1)2 (2a), [Co(MeCN)2(H2O)4][ClO4]2.(1)2 (2b), [Ni(H2O)4(NO3)2].(1)2 (3a), [Mn(H2O)4(NO3)2].(1)2 (4a), and [Mn(H2O)6][ClO4]2.(1)(4).4H2O (4b). Each network involves complete saturation of the hydrogen-bond donor sets between the aqua complex and 1 using primarily M-O-H...N(1) and M-O-H...O(anion), interactions. Thermogravimteric analysis shows these materials to have stabililities similar to coordination polymers involving metal-ligand bonds; this demonstrates that second-sphere hydrogen bonding has potential for the construction of polymeric metal-containing materials.     

Rational design of the first closed coordination capsule with octahedral outer shape

The rational synthesis of an octahedral coordination capsule in which the triangular faces are covered by single ligands is described herein. Starting with tris(2-hydroxybenzylidene)triaminoguanidinium chloride [H(6)L]Cl, we observed an oxidative cyclization of this ligand in the presence of PPh(4) (+) ions resulting in the complex [Pd(H(2)L')(PPh(3))] (1). The use of 5,5-diethylbarbiturate (bar(2-)) as a bridging ligand in the presence of [Co(en)(3)](3+) (en=ethylenediamine) leads to the formation of a rectangular box with the formula (Et(4)N)(6)[[Co[(PdCl)(Pd)L](2)(mu-bar)](2)] (2). The analysis of the architecture of compounds 1 and 2 enables the development of a self-assembly strategy for the synthesis of an octahedral coordination cage 3 with the formula Na(4)(Et(3)NH)(12)[(Pd(3)L)(8)[mu-(bar)](12)].x H(2)O. Compound 3 was characterized by (13)C-MAS-NMR spectroscopy and single-crystal structure analysis.     

Synthesis and Structural Characterization of Chiral[(n-Bu)4N]2[Mo2O5(OC10H6O)2]

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若干新型亚硝基钼硫化合物的结构特征

本文总结了若干亚硝基钼硫络合物——[(CH_3)_4N]_2K[Mo_2O(S_2)_3S_5-(NO)_2]·H_2O(Ⅰ),Na_2[Mo_4O(S_2)_6(NO)_4]·3H_2O(Ⅱ),[(CH_3)_4N]_2-Na[Mo_2O(S_2)_3S_5(NO)_2]·H_2O(Ⅲ)的结构特征。化合物(Ⅰ)和(Ⅲ)系具有相同的亚硝基钼硫阴离子的新构型化合物,其晶体分属于不同空间群。在这三个化合物中Mo原子均为畸变的五角双锥配位构型,即由5个S原子组成五角双锥的赤道面,一个桥基氧和一个NO基则分别位于五角双锥轴线上的两端。三个结构中Mo原子均通过硫桥和氧桥形成二聚或四聚。硫的配位方式显示出多样性。此外,比较三个结构,说明了Na~+,K~+阳离子对阴离子对称性的影响。     

The first coordination polymers and hydrogen bonded networks containing octahedral Nb6 clusters and alkaline earth metal complexes

Three novel coordination polymers built of octahedral niobium cyanochloride clusters [Nb6Cl12(CN)6] and alkaline earth metal complexes have been prepared by reaction of aqueous solutions of (Me4N)4Nb6Cl18 and KCN with solutions of alkaline earth metal salts and 1,10-phenanthroline (phen) (1:2 molar ratio) in H2O/EtOH. The structures of [Ca(phen)2(H2O)3]2[Nb6Cl12(CN)6] x (phen)(EtOH)1.6 (1), [Ca(phen)2(H2O)2]2[Nb6Cl12(CN)6] x (phen)2 x 4H2O (2), and [Ba(phen)2(H2O)]2[Nb6Cl12(CN)6] (3) were determined by single-crystal X-ray diffraction. The three compounds were found to crystallize in the monoclinic system (space group Pn) with a = 11.5499(6) A, b = 17.5305(8) A, c = 21.784(1) A, beta = 100.877(1) degrees for 1; triclinic system (P1) with a = 12.609(4) A, b = 13.262(4) A, c = 16.645(5) A, alpha = 69.933(6) degrees, beta = 68.607(6) degrees, gamma = 63.522(5) degrees for 2; and a = 16.057(1) A, b = 16.063(1) A, c = 16.061(1) A, alpha = 86.830(1) degrees, beta = 64.380(1) degrees, gamma = 67.803(1) degrees for 3. Compounds 1 and 2 are built of cluster anions [Nb6Cl12(CN)6]4- trans-coordinated by two Ca2+ complexes via CN ligands to form neutral macromolecular units [Ca(phen)2(H2O)3]2[Nb6Cl12(CN)6] in 1 and [Ca(phen)2(H2O)2]2[Nb6Cl12(CN)6] in 2. Water of coordination and cyanide ligands form hydrogen bonded 3D and 2D frameworks for 1 and 2, respectively. The structure of 3 consists of [Nb6Cl12(CN)6]4- cluster anions and [Ba(phen)2(H2O)]2+ complexes linked through bridging cyanide ligands to form a neutral three-dimensional framework in which each barium complex is bound to three neighboring Nb6 clusters and each Nb6 cluster is linked to six Ba complexes.     

Synthesis,Crystal Structure of Cis—dioxo—catecholatotungsten（VI） Complex and Its NMR Studies on the Interaction with ATP

Cis-dioxo-catecholatotungsten(VI) complex anion[W^(VI)O2-(OC6H4O)2]^2- was obtained with discrete protonated ethylenediamine (NH2CH2CH2NH3)^ cations by the reaction of tetrabutyl ammonium decatungstate with catechol in the mixed solvent of CH3OH,CH3CN and ethylenediamine,and compared with its molybdenum anaogue [Mo^(V) O2(OC6H4O)2]^3- by crystal structure,UV,EPR,The results of the UV and EPR spectra show that tungsten is less redox active than molybdenum since the molybdenum is reduced from Mo(VI) to Mo(V) but tungsten stays in the original highest oxidized state Mo(VI) when they are crystallized from the solution above.It is worthy to note that [W^(VI)O2(OC6H4O)]^2- shows the same coordination structure as its molybdenum analogue in which the metal center exhibits distorted octahedral coordination geometry with two cis-dioxocatecholate ligands and might have the related coordination structure feature with the cofactor of flavoenzyme because [Mo^(V)O2(OC6H4O)2]^3- presented essentially the same EPR spectra as flavoenzyme.The NMR studies on the interaction of the title complex with ATP reveal that the reduction of W(VI) to W(V) occurs when the title complex is dissolved in D2O and the W(V) is oxidized again when ATP solution is mixed with original solution and the hydrolysis of the catecholato ligand take places at mean time being monitored by ^1H NMR and ^13C NMR spectra.     

Synthesis and Crystal Structure of a Molybdenum Carbonyl Compound with Thiolate and Dithiocarbamate Ligands,[Bu4N][(OC)4Mo(μ-SC6H5)2Mo(C5H10CNS2)(CO)2]

A di-molybdenum carbonyl compound containing thiolate and dithiocarbamate li- gands, [Bu4N][(CO)4Mo(μ-SC6H5)2Mo(C5H10dtc)(CO)2] 1 (C5H10dtc = S2CNC5H10), has been pre- pared by reaction of [Mo2(SC6H5)2(CO)8] with C5H10dtcNa and [NBu4]Br in acetone. It crystallizes in monoclinic, space group P21/n with a = 13.162(3), b = 17.466(2), c = 20.453(4)(A),β = 100.77(1)°, Z = 4, V = 4619(2)(A)3, C40H56Mo2N2O6S4, Mr = 980.95, Dc = 1.389 g/cm3, μ= 7.66 cm-1, F(000) = 1988 and R = 0.0746 for 5161 observed reflections with I > 2σ(I). The complex contains a [Mo2S2]2- planar core in which one Mo atom is chelated by a C5H10dtc ligand, leading to different coordination environments of the two Mo atoms. 95Mo NMR measurement indicates that the two Mo atoms are in different oxidation states.     

Solid-state coordination chemistry: influences of (M(terpyridyl))(M = Fe(III), Cu(II), Ni(II)) subunits on molybdenum oxide structures

The hydrothermal reactions of Na2MoO4 x 2H2O and 2,2':6',2"-terpyridine with appropriate salts of Fe(II), Cu(II), and Zn(II) yield a variety of mixed metal oxide phases. The Cu(II) system affords the molecular cluster [Cu(terpy)MoO4].3H2O (MOXI-40 x 3H2O), as well as a one-dimensional material [Cu(terpy)Mo2O7](MOXI-41) which is constructed from (Mo4O14)4- clusters linked through (Cu(terpy))2+ units. In constrast, the Zn(II) phase of stoichiometry identical to that of MOXI-41, [Zn(terpy)Mo2O7](MOXI-42), exhibits a one-dimensional structure characterized by a (Mo2O7)n2n- chain decorated with peripheral (Zn(terpy))2+ subunits. The iron species [(Fe(terpy))2Mo4O12](MOXI-43) is also one-dimensional but exhibits [(Fe(terpy))2(MoO4)2]2+ rings linked through (MoO4)2- tetrahedra. A persistent structural motif which appears in MOXI-40, MOXI-41, and MOXI-43 is the [(M(terpy))2(MoO4)2]n cluster with a cyclic )(M2Mo2O4) core. In general, the secondary metal sites M(II, III) are effective bridging groups between molybdate subunits of varying degrees of aggregation. Furthermore, the ligands passivate the bimetallic oxide from spatial extension in two or three dimensions and provide a routine entree into low-dimensional structural types of the molybdenum oxide family of materials.     

New cobalt(II) and zinc(II) coordination frameworks incorporating a pyridyl-pyrazole ditopic ligand

The metal-directed assembly of new molecular frameworks incorporating 4-(4-pyridyl)pyrazole (L), containing non-linear coordination vectors, is presented. Three metallo-arrays of types [Co(LH)2(NO3)4], [Co(LH)2(H2O)4][NO3]4.H2O and [Zn2(L-H)2Cl2].2EtOH are reported. The cobalt(II) in [Co(LH)2(NO3)4] displays distorted octahedral geometry, with the two protonated pyridyl-pyrazole ligands coordinated through their pyrazole nitrogen atoms in a trans-orientation; the remaining four coordination sites are occupied by nitrate anions. Two internal hydrogen bonds occur between each pyrazole NH and the oxygens of adjacent coordinated nitrato ligands. Short intermolecular hydrogen bonds also occur between the two pyridinium hydrogens and bound nitrate ligands on different molecules to yield a two-dimensional hydrogen-bonded array. Two of these arrays interpenetrate to form an extended two dimensional layer; such layers stack throughout the crystal structure. A second product of type [Co(LH)2(H2O)4][NO3]4.H2O exists as two crystallographically independent, but chemically similar, forms. In each form, the two protonated pyridyl-pyrazole ligands occupy trans positions about the cobalt, with the remaining four coordination sites being filled by water molecules to yield a distorted octahedral coordination geometry. Intramolecular hydrogen-bonding is observed between the two non-coordinated pyrazoyl nitrogen atoms and bound water oxygen atoms. The third complex, [Zn2(L-H)2Cl2].2EtOH, contains dimer units consisting of two zinc(II) ions bridged by two pyrazoylate groups in which the coordination geometry of each zinc approximates a tetrahedron. Each zinc is bound to two deprotonated pyridine-pyrazole ligands (L-H), one pyridyl group (from a different dimeric unit) and one chloro ligand. Each pyridyl nitrogen thus connects each of these zinc dimers to an adjacent dimer unit, forming a three-dimensional network containing small voids. The latter are occupied by ethanol molecules which form hydrogen bonds to the chloro ligands.     

Na_3H_2[PMo_(10)V_2O_(40)]·16H_2O的合成与晶体结构

标题化合物的晶体属P2_1/m空间群,α=13.821(2),b=15.355(3),c=11.597(2),β=107.50(2)°,V=2347.2~3,M_r=2091.46,Z=2,D_c=2.959 g·cm~(-3),μ(MoK_o)=30.77cm~(-1),F(000)=1992。用4049个独立可观测衍射精修结构,R=0.033。杂多酸阴离子[PMo_(10)V_2O_(40)]~(5-)具有准Keggin结构,12个金属原子呈无序分布,中心原子P与两个齿顶原子M(Mo/V)在对称面上。P—O平均键长1.541(2),M—O键长1.671(2)-2.432(2)。除一个Na—O配位多面体为畸变三方锥外,其余四个Na—O配位体均为六配位。讨论了Na~+离子呈无序分布的晶体结构特征并初步总结[PMo_(10)V_2O_(40)]~(5-)在不同晶相中的构型。