SnSe2 quantum dot sensitized solar cells prepared employing molecular metal chalcogenide as precursors

A kind of molecular metal chalcogenide, (N(2)H(4))(3)(N(2)H(5))(4)Sn(2)Se(6) complex, was synthesized in the hydrazine solution and employed as the precursors for SnSe(2) deposition on TiO(2) nanocrystalline porous films. A power conversion efficiency of 0.12% under AM 1.5, 1 sun was obtained for the SnSe(2) sensitized TiO(2) solar cells.     

Selective gravimetric method for direct determination of tin(IV) with N-o-toluoyl-N-o-tolylhydroxylamine and its application to brass and bronze analyses

A selective gravimetric method for determination of tin(IV) with N-o-toluoyl-N-o-tolylhydroxylamine by direct weighing as Sn(C(15)H(14)NO(2))(2)Cl(2) is recommended. The metal complex, dried at 110-120 degrees , gives reproducible results. The method is simple, rapid and quantitative over a wide range of acidity (1-4N sulphuric acid) and is superior to existing gravimetric methods. The method works satisfactorily for determining tin in brass and bronze.     

Methyl Tin(IV) derivatives of HOTeF(5) and HN(SO(2)CF(3))(2): a solution multinuclear NMR study and the X-ray crystal structures of (CH(3))(2)SnCl(OTeF(5)) and [(CH(3))(3)Sn(H(2)O)(2)][N(SO(2)CF(3))(2)

The new tin(IV) species (CH(3))(2)SnCl(OTeF(5)) was prepared via either the solvolysis of (CH(3))(3)SnCl in HOTeF(5) or the reaction of (CH(3))(3)SnCl with ClOTeF(5). It was characterized by NMR and vibrational spectroscopy, mass spectrometry, and single crystal X-ray diffraction. (CH(3))(2)SnCl(OTeF(5)) crystallizes in the monoclinic space group P2(1)/n (a = 5.8204(8) A, b =10.782(1) A, c =15.493(2) A, beta = 91.958(2) degrees, V = 971.7(2) A(3), Z = 4). NMR spectroscopy of (CH(3))(3)SnX, prepared from excess Sn(CH(3))(4) and HX (X = OTeF(5) or N(SO(2)CF(3))(2)), revealed a tetracoordinate tin environment using (CH(3))(3)SnX as a neat liquid or in dichloromethane-d(2) (CD(2)Cl(2)) solutions. In acetone-d(6) and acetonitrile-d(3) (CD(3)CN) solutions, the tin atom in (CH(3))(3)SnOTeF(5) was found to extend its coordination number to five by adding one solvent molecule. In the strong donor solvent DMSO, the Sn-OTeF(5) bond is broken and the (CH(3))(3)Sn(O=S(CH(3))(2))(2)(+) cation and the OTeF(5)(-) anion are formed. (CH(3))(3)SnOTeF(5) and (CH(3))(3)SnN(SO(2)CF(3))(2) react differently with water. While the Te-F bonds in the OTeF(5) group of (CH(3))(3)SnOTeF(5) undergo complete hydrolysis that results in the formation of [(CH(3))(3)Sn(H(2)O)(2)](2)SiF(6), (CH(3))(3)SnN(SO(2)CF(3))(2) forms the stable hydrate salt [(CH(3))(3)Sn(H(2)O)(2)][N(SO(2)CF(3))(2)]. This salt crystallizes in the monoclinic space group P2(1)/c (a = 7.3072(1) A, b =13.4649(2) A, c =16.821(2) A, beta = 98.705(1) degrees, V = 1636.00(3) A(3), Z = 4) and was also characterized by NMR and vibrational spectroscopy.     

Organotin(IV) complexes of thiohydrazides and thiodiamines: synthesis, spectral and thermal studies

Organotin(IV) complexes of tribenzyltin(IV) chloride and di(para-chlorobenzyl)tin(IV) dichloride with thiohydrazides have been reported. The ligands synthesized were bidentate coordinating through sulphur and terminal nitrogen atoms. These form 1:1 metal-ligand complexes. The following organotin(IV) complexes have been synthesized: (C(6)H(5)CH(2))(3)Sn(L(1))Cl, (p-ClC(6)H(4)CH(2))(2)Sn(L(1))Cl(2), (C(6)H(5)CH(2))(3)Sn(L(1))Cl, (p-ClC(6)H(4)CH(2))(2)Sn(L(2))Cl(2), (C(6)H(5)CH(2))(3)Sn(L(3))Cl, (p-ClC(6)H(4)CH(2))(2)Sn(L(3))Cl(2), where (L(1)): 2-phenylethyl N-thiohydrazide, (L(2)): N-(2-phenylethyl-N-thio)-1,3-propane diamine, (L(3)): N-(2-phenylethyl-N-thio)-1,2-ethane diamine. The complexes were synthesized by directly mixing, refluxing and stirring the ligands with organotin(IV) chlorides in a suitable solvent. The complexes were found to be pure and were characterized by elemental analysis, electronic, infrared, (1)H and (13)C NMR spectroscopy. These complexes were also studied for their thermal decomposition by thermogravimetry (TG) and differential thermal analysis (DTA). Various kinetic and thermodynamic parameters, viz. activation energy (E(a)), order of reaction (n), apparent activation entropy (S(#)) and heat of reaction (DeltaH) have been determined by using Horowitz-Metzger method. It was observed that these complexes are highly stable and the thermal degradation of these complexes is a spontaneous process. The ligands and their tin complexes have also been screened for their fungitoxicity activity and found to be quite active in this respect.     

Polymorphic one-dimensional (N2H4)2ZnTe: soluble precursors for the formation of hexagonal or cubic zinc telluride

Two hydrazine zinc(II) telluride polymorphs, (N2H4)2ZnTe, have been isolated, using ambient-temperature solution-based techniques, and the crystal structures determined: alpha-(N2H4)2ZnTe (1) [P21, a = 7.2157(4) Angstroms, b = 11.5439(6) Angstroms, c = 7.3909(4) Angstroms, beta = 101.296(1) degrees, Z = 4] and beta-(N2H4)2ZnTe (2) [Pn, a = 8.1301(5) Angstroms, b = 6.9580(5) Angstroms, c = 10.7380(7) Angstroms, beta = 91.703(1) degrees, Z = 4]. The zinc atoms in 1 and 2 are tetrahedrally bonded to two terminal hydrazine molecules and two bridging tellurium atoms, leading to the formation of extended one-dimensional (1-D) zinc telluride chains, with different chain conformations and packings distinguishing the two polymorphs. Thermal decomposition of (N2H4)2ZnTe first yields crystalline wurtzite (hexagonal) ZnTe at temperatures as low as 200 degrees C, followed by the more stable zinc blende (cubic) form at temperatures above 350 degrees C. The 1-D polymorphs are soluble in hydrazine and can be used as convenient precursors for the low-temperature solution processing of p-type ZnTe semiconducting films.     

Template-assisted solvothermal synthesis of five copper(I)-thioantimonate(III) composites: crystal structures and optical and thermal properties of (C6N2H18)0.5Cu2SbS3, (C4N3H15)0.5Cu2SbS3, (C8N4H22)0.5Cu2SbS3, (C4N3H14)Cu3Sb2S5, and (C6)N4H20)0.5Cu3Sb2S5

The novel copper(I)-thioantimonates(III) (C(6)N(2)H(18))(0.5)Cu(2)SbS(3) (I) (C(6)N(2)H(16) = 1,6-diaminohexane), (C(4)N(3)H(15))(0.5)Cu(2)SbS(3) (II) (C(4)N(3)H(13) = diethylenetriamine), (C(8)N(4)H(22))(0.5)Cu(2)SbS(3) (III) (C(8)N(4)H(20) = 1,4-bis(2-aminoethyl)piperazine), (C(4)N(3)H(14))Cu(3)Sb(2)S(5) (IV) (C(4)N(3)H(13) = diethylenetriamine), and (C(6)N(4)H(20))(0.5)Cu(3)Sb(2)S(5) (V) (C(6)N(4)H(18) = triethylenetetramine) were synthesized under solvothermal conditions reacting Sb, Cu, and S with the amines. The compounds I-III belong to the RCu(2)SbS(3) structure family (R = amine) and are built up of trigonal SbS(3) pyramids and two CuS(3) moieties forming 6-membered (6 MR) and 10-membered (10 MR) rings. The rings are condensed yielding single layers which are joined into [Cu(2)SbS(3)](-) double layers via Cu-S bonds. The organic ions are located between the anionic layers, and the shortest interlayer distances are 7.8 Angstroms (I), 7.4 Angstroms (II), and 8.8 Angstroms (III). The structure of the novel inorganic-organic hybrid compound IV contains one SbS(3) group, one SbS(4) unit, two CuS(3) triangles, and one CuS(4) tetrahedron. These units are joined into four-membered (4 MR) and six-membered rings (6 MR) forming a hitherto unknown strong undulated layered (Cu(3)Sb(2)S(5))(-) anion. Anions and cations are arranged in a sandwichlike manner with an interlayer distance of 6.184 A. The new composite V contains an anion with the same chemical composition as compound IV, but the structure exhibits a unique and different network topology which is constructed by two SbS(3) pyramids, two CuS(3) triangles, and one CuS(4) tetrahedron. These units are joined into 6 MR which may be described as an inorganic graphene-like layer or as a 6(3) net. Two such layers are connected via Cu-S bonds into the final double layer. The interlayer distance amounts to 6.44 Angstroms. All compounds decompose in a more or less complex manner when heated in an inert atmosphere.     

N4H9Cu7S4: a hydrazinium-based salt with a layered Cu7S4- framework

Crystals of a hydrazinium-based copper(I) sulfide salt, N4H9Cu7S4 (1), have been isolated by an ambient temperature solution-based process. In contrast to previously reported hydrazinium salts of main-group metal chalcogenides, which consist of isolated metal chalcogenide anions, and ACu7S4 (A = NH4+, Rb+, Tl+, K+), which contains a more three-dimensional Cu7S4- framework with partial Cu-site occupancy, the structure of 1 [P21, a = 6.8621(4) A, b = 7.9851(4) A, c = 10.0983(5) A, beta = 99.360(1) degrees , Z = 2] is composed of extended two-dimensional Cu7S4- slabs with full Cu-site occupancy. The Cu7S4- slabs are separated by a mixture of hydrazinium and hydrazine moieties. Thermal decomposition of 1 into copper(I) sulfide proceeds at a significantly lower temperature than that observed for analogous hydrazinium salts of previously considered metal chalcogenides, completing the transition at temperatures as low as 120 degrees C. Solutions of 1 may be used in the solution deposition of a range of Cu-containing chalcogenide films.     

Synthesis, structure, and spectroscopic properties of Am(IO3)3 and the photoluminescence behavior of Cm(IO3)3

We have prepared Am(IO(3))(3) as a part of our continuing investigations into the chemistry of the 4f- and 5f-elements' iodates. Single crystals were obtained from the reaction of Am(3+) and H(5)IO(6) under mild hydrothermal conditions. Crystallographic data on an eight-day-old crystal are (21 degrees C, Mo Kalpha, lambda = 0.71073 Angstroms): monoclinic, space group P2(1)/c, a = 7.2300(5) Angstroms, b = 8.5511(6) Angstroms, c = 13.5361(10) Angstroms, beta = 100.035(1) degrees, V = 824.06(18), Z = 4. The structure consists of Am(3+) cations bound by iodate anions to form [Am(IO(3))(8)] units, where the local coordination environment around the americium centers is a distorted dodecahedron. There are three crystallographically unique iodate anions within the structure that bridge in both bidentate and tridentate fashions to form the overall three-dimensional structure. Repeated collection of X-ray diffraction data with time for a crystal of (243)Am(IO(3))(3) revealed an anisotropic expansion of the unit cell, presumably from self-irradiation damage, to generate values of a = 7.2159(7) Angstroms, b = 8.5847(8) Angstroms, c = 13.5715(13) Angstroms, beta = 99.492(4) degrees, V = 829.18(23) after approximately five months. The Am(IO(3))(3) crystals have also been characterized by Raman spectroscopy and the spectral results compared to those for Cm(IO(3))(3). Three strong Raman bands were observed for both compounds and correspond to the I-O symmetric stretching of the three crystallographically distinct iodate anions. The Raman profile suggests a lack of interionic vibrational coupling of the I-O stretching, while intraionic coupling provides symmetric and asymmetric components that correspond to each iodate site. Photoluminescence data for both Am(IO(3))(3) and Cm(IO(3))(3) are reported here for the first time. Assignments for the electronic levels of the actinide cations were based on these photoluminescence measurements and indicate the presence of vibronic coupling between electronic transitions and IO(3)(-) vibrational modes in both compounds.     

Strontium selenogermanate(III) and barium selenogermanate(II,IV): synthesis, crystal structures, and chemical bonding

The new selenogermanates Sr2Ge2Se5 and Ba2Ge2Se5 were synthesized by heating stoichiometric mixtures of binary selenides and the corresponding elements to 750 degrees C. The crystal structures were determined by single-crystal X-ray methods. Both compounds adopt previously unknown structure types. Sr2Ge2Se5 (P2(1)/n, a = 8.445(2) A, b = 12.302 A, c = 9.179 A, beta = 93.75(3) degrees, Z = 4) contains [Ge4Se10]8- ions with homonuclear Ge-Ge bonds (dGe-Ge = 2.432 A), which may be described as two ethane-like Se3Ge-GeSeSe2/2 fragments sharing two selenium atoms. Ba2Ge2Se5 (Pnma, a = 12.594(3) A, b = 9.174(2) A, c = 9.160(2) A, Z = 4) contains [Ge2Se5]4- anions built up by two edge-sharing GeSe4 tetrahedra, in which one terminal Se atom is replaced by a lone pair from the divalent germanium atom. The alkaline earth cations are arranged between the complex anions, each coordinated by eight or nine selenium atoms. Ba2Ge2Se5 is a mixed-valence compound with GeII and GeIV coexisting within the same anion. Sr2Ge2Se5 contains exclusively GeIII. These compounds possess electronic formulations that correspond to (Sr2+)2(Ge3+)2(Se2-)5 and (Ba2+)2- Ge2+Ge4+(Se2-)5. Calculations of the electron localization function (ELF) reveal clearly both the lone pair on GeII in Ba2Ge2Se5 and the covalent Ge-Ge bond in Sr2Ge2Se5. Analysis of the ELF topologies shows that the GeIII-Se and GeIV-Se covalent bonds are almost identical, whereas the GeII-Se interactions are weaker and more ionic in character.     

Extremely bulky amido-group 14 element chloride complexes: potential synthons for low oxidation state main group chemistry

The preparation of a series of extremely bulky secondary amines, Ar*N(H)SiR(3) (Ar* = C(6)H(2){C(H)Ph(2)}(2)Me-2,6,4; R(3) = Me(3), MePh(2) or Ph(3)) is described. Their deprotonation with either LiBu(n), NaH or KH yields alkali metal amide complexes, several monomeric examples of which, [Li(L){N(SiMe(3))(Ar*)}] (L = OEt(2) or THF), [Na(THF)(3){N(SiMe(3))(Ar*)}] and [K(OEt(2)){N(SiPh(3))(Ar*)], have been crystallographically characterised. Reactions of the lithium amides with germanium, tin or lead dichloride have yielded the first structurally characterised two-coordinate, monomeric amido germanium(II) and tin(II) chloride complexes, [{(SiR(3))(Ar*)N}ECl] (E = Ge or Sn; R = Me or Ph), and a chloride bridged amido-lead(II) dimer, [{[(SiMe(3))(Ar*)N]Pb(μ-Cl)}(2)]. DFT calculations on [{(SiMe(3))(Ar*)N}GeCl] show its HOMO to exhibit Ge lone pair character and its LUMO to encompass its Ge based p-orbital. A series of bulky amido silicon(IV) chloride complexes have also been prepared and several examples, [{(SiR(3))(Ar*)N}SiCl(3)] (R(3) = Me(3), MePh(2)) and [{(SiMe(3))(Ar*)N}SiHCl(2)], were crystallographically characterised. The sterically hindered group 14 complexes reported in this study hold significant potential as precursors for kinetically stabilised low oxidation state and/or low coordination number group 14 complexes.     

Unusual syntheses, structures, and electronic properties of compounds containing ternary, T3-type supertetrahedral M/Sn/S anions [M5Sn(mu3-S)4(SnS4)4](10- (M = Zn, Co)

A recently discovered series of quaternary compounds of the general type [K(m)(ROH)(n)()][M(x)Sn(y)()Se(z)] (R = H, Me), containing ternary anions with [SnSe(4)](4-)-coordinated transition metal centers (M = Co, Mn, Zn, Cd, Hg) has now been extended by the synthesis and characterization of the two ortho-thiostannate-coordinated species, [Na(10)(H(2)O)(32)][M(5)Sn(mu(3)-S)(4)(SnS(4))(4)].2H(2)O (M = Zn (1), Co (2)). The central structural motifs of compounds 1 and 2 are highly charged [M(5)Sn(mu(3)-S)(4)(SnS(4))(4)](10-) anions, being the first T3-type supertetrahedral ternary anions reported to date. The exposure of single crystals of 2 to a dynamic vacuum for several hours resulted in the reversible formation of a partially dehydrated, but still monocrystalline material of the composition [Na(10)(H(2)O)(6)][Co(5)Sn(mu(3)-S)(4)(SnS(4))(4)] (3). The loss of 28 of the 34 water molecules only slightly affects the internal structure of the ternary anion in 3 and leads to a significant compacting of the crystal structure with closer linkage of the [Co(5)Sn(5)S(20)](10-) cluster units via the Na(+) cations. Magnetic measurements on 3 show that the ground state of the Co/Sn/S cluster is S = 1/2, indicating a significant antiferromagnetic coupling between the Co centers, which has also been rationalized by DFT investigations of the electronic situation in the ternary subunits of 1-3.     

Reactions of collman complex with tin(IV) and germanium(IV) porphyris,formation of [tin(II) and germanium(II) porphyrins] tetracarbonyliron and crystal structure of [2,3,7,8,12,13,17,18-octaethylporphinato tin(II)] tetracarbonyliron

The action of Na₂Fe(CO)₄ with tin(IV) and germanium(IV) porphyrins affords metal(II) porphyrin complexes [(por)M(II)Fe(CO)₄] (por = porphyrinate, M - Sn(II) or Ge(II)). The molecular structure of [(oep)Sn(II)Fe(CO)₄] was solved by X-ray diffraction techniques. The molecular structure of [(oep)Sn(II)Fe(CO)₄] was solved by X-ray diffraction techniques : the Sn coordination is square pyramidal with the iron in axial position (Sn-Fe = 2.492(1)Å) whereas the Fe coordination is trigonal bipyramidal. Mössbauer parameters provide convincing evidence for the formal zero oxidation state of the iron atom.     

Preparation,structures, and redox and emission characteristics of the isothiocyanate complexes of hexarhenium(III) clusters [Re6(mu3-E)8(NCS)6]4- (E = S,Se)

Hexarhenium(III) complexes with terminal isothiocyanate ligands, [(n-C(4)H(9))(4)N](4)[Re(6)(mu(3)-S)(8)(NCS)(6)] (1) and (L)(4)[Re(6)(mu(3)-Se)(8)(NCS)(6)] (L(+) = PPN(+) (2a), (n-C(4)H(9))(4)N(+) (2b)), have been prepared by three different methods. Complex 1 was prepared by the reaction of [(n-C(4)H(9))(4)N](4)[Re(6)(mu(3)-S)(8)Cl(6)] with molten KSCN at 200 degrees C, while 2b was obtained by refluxing the chlorobenzene-DMF (2:1 v/v) solution of [Re(6)(mu(3)-Se)(8)(CH(3)CN)(6)](SbF(6))(2) and [(n-C(4)H(9))(4)N]SCN. The [Re(6)(mu(3)-Se)(8)(NCS)(6)](4)(-) anion was also obtained from a mixture of Cs(2)[Re(6)(mu(3)-Se)(8)Br(4)] and KSCN in C(2)H(5)OH by a mechanochemical activation at room temperature for 20 h and isolated as 2a. The X-ray structures of 1 and 2a.4DMF have been determined (1, C(70)H(144)N(10)S(14)Re(6), monoclinic, space group P2(1)/n (No. 14), a = 14.464(7) A, b = 22.059(6) A, c = 16.642(8) A, beta = 113.62(3) degrees, V = 4864(3) A(3), Z = 2; 2a.4DMF, C(162)H(144)N(14)O(4)P(8)S(6)Se(8)Re(6), triclinic, space group P1 (No. 2), a = 15.263(2) A, b = 16.429(2) A, c = 17.111(3) A, alpha = 84.07(1) degrees, beta = 84.95(1) degrees, gamma = 74.21(1) degrees, V = 4098.3(8) A(3), Z = 1). All the NCS(-) ligands in both complexes are coordinated to the metal center via nitrogen site with the Re-N distances in the range of 2.07-2.13 A. The redox potentials of the reversible Re(III)(6)/Re(III)(5)Re(IV) process in acetonitrile are +0.84 and +0.70 V vs. Ag/AgCl for [Re(6)(mu(3)-S)(8)(NCS)(6)](4)(-) and [Re(6)(mu(3)-Se)(8)(NCS)(6)](4)(-), respectively, which are the most positive among the known hexarhenium complexes with six terminal anionic ligands. The complexes show strong red luminescence with the emission maxima (lambda(max)/nm), lifetimes (tau(em)/micros), and quantum yields (phi(em)) being 745 and 715, 10.4 and 11.8, and 0.091 and 0.15 for 1 and 2b, respectively, in acetonitrile. The data reasonably well fit in the energy-gap plots of other hexarhenium(III) complexes. The temperature dependence of the emission spectra and tau(em) of 1 and [(n-C(4)H(9))(4)N](4)[Re(6)(mu(3)-S)(8)Cl(6)] are also reported.     

Novel organotellurium(IV) diazides and triazides

New series dialkyltellurium(IV) diazides R(2)Te(N(3))(2) (R = CH(3) (6), C(2)H(5) (7), n-C(3)H(7) (8), i-C(3)H(7) (9), c-C(6)H(11) (10)) and alkyl/aryltellurium(IV) triazides R'Te(N(3))(3) (R' = CH(3) (11), C(2)H(5) (12), n-C(3)H(7) (13), i-C(3)H(7) (14), C(6)H(5) (15), 2,4,6-(CH(3))(3)C(6)H(2) (16)) were synthesized by the straightforward substitution of fluorine atoms in the corresponding tellurium difluorides, or trifluorides respectively, with trimethylsilyl azide. In addition to standard characterization methods, the first crystal structures of covalent organotellurium(IV) triazides 12, 13, 14, and 16 have been determined. Ethyltellurium(IV) triazide, C(2)H(5)Te(N(3))(3) (12), crystallizes in the monoclinic space group P2(1)/n, a = 8.4530(2) A, b = 7.9094(2) A, c = 12.6288(3) A, beta = 91.876(1). n-Propyltellurium(IV) triazide, n-C(3)H(7)Te(N(3))(3) (13), crystallizes in the monoclinic space group P2(1)/n as well, a = 8.7999(2) A, b = 7.9674(2) A, c = 13.2334(3) A, beta = 94.626(1). Isopropyltellurium(IV) triazide, i-C(3)H(7)Te(N(3))(3) (14), crystallizes in the monoclinic space group C2/c, a = 20.058(2) A, b = 6.9620(3) A, c = 15.030(1) A, beta = 114.260(9). Mesityltellurium(IV) triazide, 2,4,6-(CH(3))(3)C(6)H(2)Te(N(3))(3) (16), crystallizes monoclinic as well; the space group is P2(1)/c, a = 7.5503(6) A, b = 23.581(1) A, c = 7.5094(6) A, beta = 91.295(9). The structures and vibrational frequencies of the methyl derivatives dimethyltellurium(IV) diazide (6) and methyltellurium(IV) triazide (11) have been calculated by density functional theory methods and were compared with the experimental metric parameters and vibrational data.     

Synthesis and characterization of iron(III)-substituted, dimeric polyoxotungstates, [Fe(4)(H(2)O)(10)(beta-XW(9)O(33))(2)](n-) (n = 6, X = As(III), Sb(III); n = 4, X = Se(IV), Te(IV))

Interaction of the lacunary [alpha-XW(9)O(33)](9-) (X = As(III), Sb(III)) with Fe(3+) ions in acidic, aqueous medium leads to the formation of dimeric polyoxoanions, [Fe(4)(H(2)O)(10)(beta-XW(9)O(33))(2)](6-) (X = As(III), Sb(III)) in high yield. X-ray single-crystal analyses were carried out on Na(6)[Fe(4)(H(2)O)(10)(beta-AsW(9)O(33))(2)] x 32H(2)O, which crystallizes in the monoclinic system, space group C2/m, with a = 20.2493(18) A, b = 15.2678(13) A, c = 16.0689(14) A, beta = 95.766(2) degrees, and Z = 2; Na(6)[Fe(4)(H(2)O)(10)(beta-SbW(9)O(33))(2)] x 32H(2)O is isomorphous with a = 20.1542(18) A, b = 15.2204(13) A, c = 16.1469(14) A, and beta = 95.795(2) degrees. The selenium and tellurium analogues are also reported, [Fe(4)(H(2)O)(10)(beta-XW(9)O(33))(2)](4-) (X = Se(IV), Te(IV)). They are synthesized from sodium tungstate and a source of the heteroatom as precursors. X-ray single-crystal analysis was carried out on Cs(4)[Fe(4)(H(2)O)(10)(beta-SeW(9)O(33))(2)] x 21H(2)O, which crystallizes in the triclinic system, space group P macro 1, with a = 12.6648(10) A, b = 12.8247(10) A, c = 16.1588(13) A, alpha = 75.6540(10) degrees, beta = 87.9550(10) degrees, gamma = 64.3610(10) gamma, and Z = 1. All title polyanions consist of two (beta-XW(9)O(33)) units joined by a central pair and a peripheral pair of Fe(3+) ions leading to a structure with idealized C(2h) symmetry. It was also possible to synthesize the Cr(III) derivatives [Cr(4)(H(2)O)(10)(beta-XW(9)O(33))(2)](6-) (X = As(III), Sb(III)), the tungstoselenates(IV) [M(4)(H(2)O)(10)(beta-SeW(9)O(33))(2)]((16)(-)(4n)-) (M(n+) = Cr(3+), Mn(2+), Co(2+), Ni(2+), Zn(2+), Cd(2+), and Hg(2+)), and the tungstotellurates(IV) [M(4)(H(2)O)(10)(beta-TeW(9)O(33))(2)]((16-4n)-) (M(n+) = Cr(3+), Mn(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), and Hg(2+)), as determined by FTIR. The electrochemical properties of the iron-containing species were also studied. Cyclic voltammetry and controlled potential coulometry aided in distinguishing between Fe(3+) and W(6+) waves. By variation of pH and scan rate, it was possible to observe the stepwise reduction of the Fe(3+) centers.     

Titanium(IV) citrate speciation and structure under environmentally and biologically relevant conditions

The water-soluble complexes of Ti(IV) with citrate are of interest in environmental, biological, and materials chemistry. The aqueous solution speciation is revealed by spectropotentiometric titration. From pH 3-8, given at least three equivalents of ligand, 3:1 citrate/titanium complexes predominate in solution with successive deprotonation of dangling carboxylates as the pH increases. In this range and under these conditions, hydroxo- or oxo-metal species are not supported by the data. At ligand/metal ratios between 1:1 and 3:1, the data are difficult to fit, and are consistent with the formation of such hydroxo- or oxo- species. Stability constants for observed species are tabulated, featuring log beta-values of 9.18 for the 1:1 complex [Ti(Hcit)](+), and 16.99, 20.41, 16.11, and 4.07 for the 3:1 complexes [Ti(H(2)cit)(3)](2-), [Ti(H(2)cit)(Hcit)(2)](4-), [Ti(Hcit)(2)(cit)](6-), and [Ti(cit)(3)](8-), respectively (citric acid = H(4)cit). Optical spectra for the species are reported. The complexes exhibit similar yet distinct spectra, featuring putative citrate-to-Ti(IV) charge-transfer absorptions (lambda(max) approximately 250-310 nm with epsilon approximately 5000-7000 M(-)(1) cm(-1)). The prevailing 3:1 citrate/titanium ratio in solution is supported by electrospray mass spectrometry data. The X-ray crystal structure of a fully deprotonated tris-citrate complex Na(8)[Ti(C(6)H(4)O(7))(3)].17H(2)O (1) (or Na(8)[Ti(cit)(3)].17H(2)O) that crystallizes from aqueous solution at pH 7-8 is reported. Compound 1 crystallizes in the triclinic space group P, with a = 11.634(2) Angstroms, b = 13.223(3) Angstroms, c = 13.291(3) Angstroms, V = 1982.9(7) Angstroms(3), and Z = 2.     

Syntheses and Crystal Structures of Two Mononuclear Tin（IV） Complexes Derivedfrom Sn（edt）2 （edt = Ethane-1,2-dithiolate）

1INTRODUCTIONRecentlythedesignandsynthesisoftinsulfide-basedsolidstatematerialshasreceivedmuchattentionowningtotheirinterestingoptical,catalyticandelectricalpropertiesfordeviceappli-cations[1].Becauseoftheversatilecoordinationcharacteristicsoftinandsulfur…     

1,2-Distanna-closo-dodecaborate--a rare example of a 1,2-distannylene ligand in transition metal chemistry

The coordination chemistry of the novel bidentate tin ligand 1,2-distanna-closo-dodecaborate is illustrated for the first time by reactions with molybdenum, platinum and gold metal complexes. Up to three clusters coordinate two metal centers in close proximity. For all these metal complexes the typical μ-bridging coordination mode was observed exclusively. Furthermore, two cluster anions react with dichloromethane via substitution of the chloride ions. The carbon functionalized tin cluster [Et(4)N](2)[CH(2)(Sn(2)B(10)H(10))(2)] and the coordination complexes [Et(3)NMe](6)[Mo(2)(CO)(6)(Sn(2)B(10)H(10))(3)], [Et(3)NMe](2)[{HPt(PEt(3))(2)(Sn(2)B(10)H(10))}(2)], [Et(4)N](2)[{HPt(PPh(3))(2)(Sn(2)B(10)H(10))}(2)] and [{(TP)Au}(2)(Sn(2)B(10)H(10))] (TP = PhP(o-Ph(2)PC(6)H(4))(2)) are fully characterized by multinuclear NMR spectroscopy, elemental analyses and crystal structure analyses.     

Synthesis and Structure of Ba(2)Sn(3)Sb(6), a Zintl Phase Containing Channels and Chains

The new Zintl phase dibarium tritin hexaantimonide, Ba(2)Sn(3)Sb(6) has been synthesized, and its structure has been determined by single-crystal X-ray diffraction methods. It crystallizes in the orthorhombic space group -Pnma with a = 13.351(1) ?, b = 4.4100(5) ?, c = 24.449(3) ?, and Z = 4 (T = -50 degrees C). The structure of Ba(2)Sn(3)Sb(6) comprises large channels [010] defined by 30-membered rings constructed from an anionic framework. This framework is built up from Sn-centered trigonal pyramids and tetrahedra, as well as zigzag chains of Sb atoms. Within the channels reside the Ba(2+) cations and additional isolated zigzag Sb-Sb chains. The simultaneous presence of Sn trigonal pyramids and tetrahedra implies that Ba(2)Sn(3)Sb(6) is a mixed-valence compound whose oxidation state notation can be best represented as (Ba(2+))(2)[(Sn(II))(2)(Sn(IV))(Sb(-)(III))(3)(Sb(-)(I))](2)(-)[(Sb(-)(I))(2)](2)(-).     

Diaminogermylene and diaminostannylene derivatives of gold(I): novel AuM and AuM2 (M = Ge, Sn) complexes

The reactions of [AuCl(THT)] (THT = tetrahydrothiophene) with 1 equiv of the group 14 diaminometalenes M(HMDS)(2) [M = Ge, Sn; HMDS = N(SiMe(3))(2)] lead to [Au{MCl(HMDS)(2)}(THT)] [M = Ge (1), Sn (2)], which contain a metalate(II) ligand that arises from insertion of the corresponding M(HMDS)(2) reagent into the Au-Cl bond of the gold(I) reagent. While compound 1 reacts with more Ge(HMDS)(2) to give the germanate-germylene derivative [Au{GeCl(HMDS)(2)}{Ge(HMDS)(2)}] (3), which results from substitution of Ge(HMDS)(2) for the THT ligand of 1, an analogous treatment of compound 2 with Sn(HMDS)(2) gives the stannate-stannylene derivative [Au{SnCl(HMDS)(2)}{Sn(HMDS)(2)(THT)}] (4), which has a THT ligand attached to the stannylene tin atom and which, in solution at room temperature, participates in a dynamic process that makes its two Sn(HMDS)(2) fragments equivalent (on the NMR time scale). A similar dynamic process has not been observed for the AuGe(2) compound 3 or for the AuSn(2) derivatives [Au{SnR(HMDS)(2)}{Sn(HMDS)(2)(THT)}] [R = Bu (5), HMDS (6)], which have been prepared by treating complex 4 with LiR. The structures of compounds 1 and 3-6 have been determined by X-ray diffraction.