Diphenylantimony(III) acetate: spectra and crystal structure

Infrared data suggest that diphenylantimony acetate has a polymeric structure with bridging acetate groups which is partially broken down in carbon tetrachloride solution and completely destroyed in chloroform. The solid state structure has been determined by X-ray crystallography. The compound is triclinic, space group P$\text{1}$, with a 10.61(1), b 13.36(1), c 11.07(1) Å, α 106.9(1), β 116.7(1), γ 93.7(1)° and Z  4. The two independent antimony atoms are linked into polymeric chains by bridging acetate groups and are in pseudo trigonal bipyramidal coordination. The two phenyl groups (mean SbC, 2.155 Å) and the antimony lone pair occupy the equatorial positions while one axial position is occupied by an oxygen of the bonded acetate group (SbO, 2.137 Å).The bridge bonds occupy the second axial position leading to distances of 2.592 and 2.513 Å to Sb(1) and Sb(2).     

Recognition of linear and bent forms of solid μ-oxo-bis[iodotriphenylantimony(V)] (Ph3SbI)2O

Two quite different shapes of the (Ph₃SbI)₂O molecule are found in separate crystals, namely 1a, in which the SbOSb bridge is linear with bond distances of 1.9410–1.9437(6) Å and 1b in which the SbOSb angle is 144.6(4)° and the SbO bonds are longer, averaging 1.971(8) Å. The two species also give distinct vibrational spectra. Both arise from the reaction of triphenylantimony with iodine in moist acetonitrile, 1a as the initial crop of colourless crystals and 1b as organe crystals left when the solution is allowed to evaporate to dryness.     

New hydrogen-bonded dimeric and polymeric gold(I) complexes of the heterodifunctional ligand Ph2PNHP(O)Ph2

The preparation of several new gold(I) complexes by chloride metathesis of [AuCl(HL)] [HL=Ph₂PNHP(O)Ph₂] with either HL or K[Ph₂P(E)NP(E)Ph₂] (E=S or Se) is described. All compounds were characterised by a combination of ³¹P{¹H}, ¹H and IR spectroscopy, microanalysis and X-ray crystallography. X-ray structural studies reveal that [Au(HL)₂]Cl [monoclinic, space group P2₁/c, a=9.0726(3) Å, b=21.0847(6) Å, c=12.0131(3) Å, β=105.1090(10)°, V=2219 ų, Z=2, final R=3.97] forms a one dimensional polymeric structure in which alternating [Au(HL)₂]⁺ and Cl⁻ ions are linked through intermolecular N–H⋯Cl hydrogen-bonding. In contrast the three-co-ordinate compound [Au{Ph₂P(Se)NP(Se)Ph₂-Se,Se′}(HL)] [monoclinic, space group P2₁/a, a=21.6752(5) Å, b=9.1200(10) Å, c=24.0742(7) Å, β=106.080(2)°, V=4573 ų, Z=4, final R=8.94] forms hydrogen-bonded dimer pairs analogous to that previously observed in non-complexed HL. The X-ray crystal structure of the gold(I) precursor [AuCl(HL)] has also been determined: monoclinic, space group P2₁/c, a=10.217(8) Å, b=23.256(5) Å, c=20.086(5) Å, β=101.15(4)°, V=4683 ų, Z=8, final R=5.2. The X-ray crystal structure reveals intermolecular N–H⋯OP hydrogen-bonding between adjacent [AuCl(HL)] molecules forming infinite chains.     

A dichromium(II) compound with an elongated metal-metal bond: Cr2(oxindolate)4(oxindole)2

The title compound has been prepared by reaction of (C₅H₅)₂Cr with oxindole (indole with CO in place of CH₂ at the 2-position). Red single crystals belong to space group P2₁/c with a = 10.107(4) Å, b = 22.496(7) Å, c = 9.210(3) Å, β = 93.26(3)°, V = 2091(2), and Z = 2. The centrosymmetric molecule has a CrCr distance of 2.495(4) Å. The mean CrO and CrN distances for the bonds to bridging oxindolate anions are 2.024(7) and 2.065(8) Å, respectively. There is an oxindole molecule bound at each end with a CrO axial bond of length 2.341(8) Å and a hydrogen bond from the oxindole NH group to an equatorial oxygen atom of length 2.83(1) Å. The significance of this compound with respect to CrCr bonding is discussed.     

Molecular structure of two dicyclopentadienylmolybdenum derivatives containing a four-membered ring [Mo(η5-C5H5)2(2-NHNC5H4)][PF6] and [Mo(η5C5H5)2(2-ONC5H4)][PF6]

The structure of the new compound [Mo(η⁵-C₅H₅)₂(2-NHNC₅H₄)][PF₆] (1) has been determined. The crystals are orthorhombic, space group Pca2₁ with a 20.807(1), b 8.0030(8), c 10.056(3) Å, V 1674.5 ų, Z = 4. The structure of [Mo(η⁵-C₅H₅)₂(2-ONC₅H₄)][PF₆] (2) has also been determined. The crystals are orthorhombic, space group Pnma with a 12.727(3), b 10.174(2), c 12.918(1) Å, V 1672.8 ų, Z = 4. The structures were solved by Patterson and difference electron density syntheses and refined by least-squares to R of 0.028 for 1287 reflections for 1 and 0.059 for 1178 reflections for 2.Although not isostructural the two cationic complexes have equivalent geometries with the normal bent bismetallocene structure. For 1 the MoN bond lengths are 2.160(8) and 2.142(9) Å, with a NMoN bond angle of 59.8(3)°, whereas for 2 MoO is 2.142(10), MoN is 2.138(11) Å, the NMoO angle is 61.2(4)°. These parameters are discussed and compared with the corresponding data for similar biscyclopentadienyl complexes of molybdenum(IV). Extended Hückel molecular orbital calculations have been carried out to throw light on the nature of the bonding between the metal and the bidentate ligand.     

Monomeric five-coordinate rhenium diazenido and hydrazido complexes with aromatic thiolate ligands: X-ray structures of [Re(NNC6H4-Br)2(SC6H3-2,5-Me2)(PPh3)2] and [ReO(NNMePh)(SPh)3], and of the synthetic precursor [Re(NNC6H4-4-Br)2Cl(PPh3)2]

Reaction of [ReOCl₃(PPh₃)₂] with bromophenylhydrazine in methanol yields [ReCl(N₂C₆H₄Br)₂(PPh₃)₂] (1). Complex 1 reacts with arylthiolates to give mixtures of [Re(SAr)(N₂C₆H₄Br)₂(PPh₃)₂] (2) and [Re₂(SAr)₇(NNR)₂]⁻. Complexes 1 and 2 display trigonal bipyramidal geometries with the phosphine ligands occupying the axial sites. A significant feature of the structures is the nonequivalence of the rhenium-diazenido moieties, such that for 1 the ReN(1) and N(1)N(2) distances are 1.80(2) and 1.24(3) Å, while ReN(3) and N(3)N(4) are 1.73(2) and 1.32(3) Å, and for 2 the ReN distances are 1.73(1) and 1.80(2)° with corresponding NN distances of 1.32(2) and 1.25(2) Å. Reaction of (PPh₄)[ReO(SPh)₄] (3) with unsymmetrically disubstituted hydrazines affords complexes of the type [ReO(SPh)₃(NMRR′)] (R = Me, R′ = Ph for 4). Complexes 3 and 4 display distorted square pyramidal geometries with the oxo groups apical. The significant feature of the structure of 4 is the nonlinear ReN(1)N(2) linkage, exhibiting an angle of 145.6(10)°. The angle does not appear to correlate with a significant contribution from a valence form with sp² hybridization at the α-nitrogen. Crystal data: 1: monoclinic space group, P2₁/n, a = 12.216(2) Å, b = 19.098(2) Å, c = 20.257(4) Å, β = 106.20(1)°, V = 4538.3(8) ų to give Z = 4; structure solution and refinement based on 1905 reflections converged at R = 0.070. 2: monoclinic space group P2₁/n, a = 14.393(2) Å, b = 18.842(3) Å, c = 20.717(4)Å, β = 110.26(1)°, V = 5270.5(8) ų to give Z = 4 for D = 1.53 g cm⁻¹; structure solution and refinement based on 4249 reflections to give R = 0.070. 3: monoclinic space group P2₁/n, a = 12.531(2) Å, b = 24.577(4) Å, c = 16.922(3) Å, β = 99.06(1)°, V = 5146.2(9) ų, D = 1.36 g cm⁻³ for Z = 4, 2912 reflections, R = 0.050. 4: monoclinic space group p2₁/n, a = 16.137(2) Å, b = 9.863(2) Å, c = 16.668(2) Å, β = 111.12(1)°, V = 2474.7(6) ų, D = 1.74 g cm⁻³ for Z = 4, 2940 reflections, R = 0.066.     

A binuclear tantalum(III) complex with a bridging carboxylato ligand

Ta₂Cl₆(SMe₂)₃ reacts with one equivalent of C₄H₉CO₂Li to give a complex with a bridging carboxylate ligand, Ta₂Cl₅(O₂CC₄H₉)(SMe₂)(THF)₂. The product was isolated in two crystalline forms, 1 and 2, from a THF/hexane and benzene/hexane solvent mixture, respectively. The following are the unit cell parameters, for 1: monoclinic (P2₁/n), a = 10.537(5) Å, b = 22.015(4) Å, c = 11.663(4) Å, β = 107.80(3)°, V = 2576(3) ų, and Z = 4; for 2: monoclinic (P2₁/c), a = 15.584(4) Å, b = 15.647(4) Å, c = 11.275(3) Å, β = 106.04(5)°, V = 2642(3) ų and Z = 4. The complex is a dimer with a distorted octahedra-sharing-an-edge geometry. The TaTa distances in 1 and 2 were 2.766(1) Å and 2.779(1) Å, respectively, which is somewhat longer than in previously reported Nb(III) and Ta(III) dinuclear compounds. Diamagnetism of the complex is shown by NMR. Fenske—Hall calculations, which correctly predict an electronic transition at about 16,000 cm^?1, indicate a double TaTa bond. The observed elongation of the metalmetal bond is attributed mainly to steric crowding. The complex is the first proven low-valent Ta species with a coordinated carboxylate ion.     

Skew-trapezoidal bipyramidal diorganotin(IV) bischelates. Crystal structure of dimethylbis(2-pyridinethiolato-N-oxide)tin(IV)

Dimethylbis(2-pyridinethiolato-N-oxide)tin(IV), Me₂Sn(2-SPyO)₂, crystallizes in space group P2₁/c with a 9.877(3), b 11.980(4), c 13.577(3) Å, β 109.1(2)° and Z = 4. The structure was refined to R_F = 0.036 for 2263 Mo-K_α observed reflections. The coordination geometry at tin is a skew-trapezoidal bipyramid, with the oxygen [SnO 2.356(3), 2.410(4) Å] and sulfur [SnS 2.536(1), 2.566(1) Å] atoms of the chelating groups occupying the trapezoidal plane and the methyl groups [SnC 2.106(6), 2.128(7) Å] occupying the apical positions. The methyl-tin-methyl skeleton is bent [CSnC 138.9(2)°]. The SSnS angle is 77.8(1)°, but the OSnO angle is opened to 136.7(1)° to accommodate the intruding methyl groups. The carbontincarbon angles predicted from quadrupole splitting (^119mSn Mössbauer) and one-bond ¹¹⁹Sn¹³C coupling constant (solution ¹³C NMR) data agree closely with the experimental value.     

The crystal and molecular structure of bis-dimethylaminotitanium difluoride tetramer

The crystal structure of [(Me₂N)₂TiF₂₄ has been determined by single-crystal X-ray diffraction. The crystals are tetragonal, I$\text{4}$, a = b = 11.313(5), c = 12.862(4) Å, Z = 2. The titanium atoms display a distorted octahedral coordination and are linked by TiFTi and TiNMe₂Ti bridges to form a tetramer, which possesses a crystallographic inverse tetrad axis at its centre. One fluorine and one dimethylamino group do not participate in the bridging. The principal bond lenghts are TiF(bridging) 2.00(2) and 2.06(2), TiF (terminal) 1.77(2), TiN(bridging) 2.14(3) and 2.19(3), TiN(terminal) 1.99(30) Å. The structure has been refined to R = 0.077 for 231 visually estimated unique reflections.     

Two zincophosphite frameworks templated by 1,4-diaminobenzene: syntheses and structures of C6N2H10·Zn(HPO3)2 and (C6N2H8)0.5·ZnHPO3

The solution-mediated syntheses and single crystal structures of C₆N₂H₁₀·Zn(HPO₃)₂ (I) and (C₆N₂H₈)_0.5·ZnHPO₃ (II) are reported. Slight variation of the synthesis conditions led to two quite different phases. I contains infinite chains of ZnO₄ and HPO₃ groups with the protonated organic moiety acting as a template and interacting with the chains by NH⋯O hydrogen bonds and possible CH⋯O interactions. In II, the neutral 1,4-diamino benzene molecule bonds to Zn (as a ligand) and an unusual composite, “pillared”, structure results, with the organic species bridging 6³ polyhedral sheets, although NH⋯O bonds are also present. Similarities and differences to other zinc phosphites and phosphates are briefly discussed for I and II. Crystal data: C₆N₂H₁₀·Zn(HPO₃)₂, M_r=335.48, monoclinic, C2/c (No. 15), a=17.2471 (14) Å, b=9.0720 (8) Å, c=7.6529 (6) Å, β=103.752 (2)°, V=1163.09 (7) Å³, Z=4, R(F)=0.038, wR(F²)=0.084. (C₆N₂H₈)_0.5·ZnHPO₃, M_r=199.42, orthorhombic, Pbca (No. 61), a=8.0314 (16) Å, b=8.1299 (16) Å, c=18.830 (4) Å, V=1229.5 (4) Å³, Z=8, R(F)=0.026, wR(F²)=0.055.     

New compounds in the cesium sulfobromide rhenium octahedral cluster chemistry: syntheses and crystal structures of Cs4Re6S8Br6 and Cs2Re6S8Br4

The exploration of the CsReSBr system, in order to identify new phases based on octahedral cluster anions, has produced single crystals of Cs₄Re₆S₈Br₆ (1) (trigonal, space group P-6c2, a=9.7825 (3) Å, c=18.7843 (5) Å, V=1556.77 (1) ų, Z=2, density=5.09 g cm⁻³, μ=36.07 mm⁻¹) and Cs₂Re₆S₈Br₄ (2) (monoclinic, space group P2₁/n, a=6.3664 (1) Å, b=18.4483 (4) Å, c=9.3094 (2) Å, β=104.2618 (8)°, V=1059.69 (4) ų, Z=2, density=6.14 g cm⁻³, μ=45.83 mm⁻¹). These two compounds have been obtained by high-temperature solid state route. Their structures have been solved and refined from single crystal X-ray diffraction data. The structure of Cs₄Re₆S₈Br₆ presents isolated anionic cluster units inscribed in a (Cs⁺)₁₂ cuboctahedron and the one of Cs₂Re₆S₈Br₄ exhibits ReS^i-a,a-iRe inter-unit bridges. The framework of the latter presents then a strongly 1-D character.     

The first nickel(II) allogon of a ditertiary phosphine ligand: Preparation,spectral and crystallographic characterization of square-planar bis(diphenylphosphinomethyl)dimethylsilanedinitratonickel(II)

The reaction of nickel(II) nitrate with bis(diphenylphosphinomethyl)dimethylsilane in ethanol solution gives Ni(NO₃)₂ · (Ph₂PCH₂)₂SiMe₂, recrystallized as orange and violet crystals from dichloromethane. Vibrational, electronic spectral and magnetic measurements of the initial product indicate the presence of allogons, the first case involving nitrate anions or a ditertiary phosphine ligand. The structure of the orange crystals 1 was determined by single-crystal X-ray diffraction analysis. The crystals are monoclinic, space group P2₁/c with four molecules in a unit cell of dimensions a = 10.512(2), b = 15.821(5), c = 18.948(8) Å, β = 104.87(4)°. The structure was solved by the heavy-atom method and refined by full-matrix least-squares calculations to R = 0.029 for 2563 observed data. In the monomeric molecule the Ni atoms are square planar, with monodentate nitrate groups [NiO = 1.926(2) and 1.933(2) Å]. The bidentate phosphine ligand has a bite angle of 94.81(3)° and the NiP bond distances are 2.166(1) and 2.170(1) Å. The six-membered NiP₂C₂Si ring adopts a boat conformation.     

The dinuclear unit μ-aqua-bis(μ-carboxylato)dimetal. X-ray structure and magnetism of cobalt and nickel(II) compounds containing bridging carboxylato groups and a bridging water molecule

The syntheses, characterization, X-ray structure and magnetism of a number of dinuclear compounds, with general formula M₂(μ-OH₂)(μ-O₂CR)₂(O₂CR)₂(tmen)₂ are described. In this formula M = Co(II), Ni(II), R = CH₃, CH₂Cl, CHCl₂, and CCl₃, and tmen stands for N,N,N′,N′-tetramethyl-1,2-diaminoethane.The X-ray structures of two examples, M = Co and R = CCl₃(I) and M = Co, Ni and R = CH₂Cl(II) are described in detail. Compound I crystallizes in space group P2₁/c, with a = 23.610(7), b = 10.439(2) and c = 17.920(4) Å, β = 110.43(4)° and Z = 4. Using 5196 measured reflections collected on a diffractometer with graphite monochromatized Mo-Kα radiation, the structure was refined to R = 0.089. The dimeric units Co₂(OH₂)(O₂CCl₃)₂ [Co … Co = 3.696(3) Å, angle CoOCo = 116.1(6)°] resemble very much those of earlier reported structures with M = Ni, Co and other bridging carboxylato anions. Apart from the two bridging carboxylato anions, two monodentate CCl₃CO⁻₂ anions are present, in addition to the normal bidentate tmen ligands, completing the octahedral geometry for each metal ion. The dimeric structure, with the bridging water ligand, appears to be highly stabilized by intramolecular hydrogen bonding with one of the oxygens of the monodentate CCl₃CO⁻₂ ligands (O … O contacts of 2.56–2.60 Å). This stabilization by hydrogen bonding appears to be very similar to the proposed hydrogen bonding in hemerythrine, in which the coordinated dioxygen seems to be hydrogen bonded with the bridging -OH group.Compound II has essentially the same basic structure; it crystallizes also in the space group P2₁/c, with a = 16.034(7), b = 13.114(7), c = 15.344(7), β = 91.20(4) and Z = 4. From 4701 measured reflections the structure was refined to R = 0.043. The dimeric units exhibit a Co-Ni distance of 3.596(1) Å, with a Ni-O-Co angle of 116.5°. The slightly smaller distances around Ni(II) made distinction from Co(II) possible.The metal ions in these Co and Ni compounds are antiferromagnetically coupled, just as the Fe ions in hemerythrine. This antiferromagnetic interaction has been studied by low-temperature magnetic susceptibility measurements. The magnitude of the coupling appears to vary as a function of the metal, the M … M distance and the MOM angle.     

A study of the structure and properties of mixed-ligand Cu(II) complexes with hexafluoroacetylacetone and methyl-, phenyl-ketoimines

The synthesis and X-ray single crystal study of two mixed-ligand Cu(II) complexes are performed: (CH₃C(NCH₃)CHC(O)CH₃)(CF₃C(O)CHC(O)CF₃)Cu (1) (space group P2₁/c, a = 7.0848(12) Å, b = 17.854(3) Å, c = 11.837(2) Å, β = 100.495(6)°, V = 1472.4(4) ų, Z = 4), (CH₃C(NC₆H₅)CHC(O)CH₃)· (CF₃C(O)CHC(O)CF₃)Cu (2) (space group P-1, a = 9.1119(4) Å, b = 9.6954(4) Å, c = 11.1447(6) Å, α = 113.784(2)°, β = 92.383(2)°, γ = 95.402(2)°, V = 893.52(7) ų, Z = 2). The structures are molecular, formed from neutral mixed-ligand copper complexes. The central copper atom has the (3O+N) coordination environment with average Cu-O distances of 1.948 Å and Cu-N of 1.932 Å; the chelate O-Cu-N angle (average) is 94.0°. In the structures, the complexes are linked into dimeric associates with Cu…Cu distances of 3.197 Å (for 1) and 3.246 Å (for 2). The volatility of mixed-ligand complexes 1 and 2 is in between of that of the starting homo-ligand complexes.     

Metal-silicon bonded compounds : X. The molecular structures of 2,2,4,4,6,6,8,8-octamethyl-2,4,6,8-tetrasila-1,5-mercuracyclooctane and bis(triphenylsilyl) mercury

The crystal and molecular structure determinations of 2,2,4,4,6,6,8,8-octamethyl-2,4,6,8-tetrasila-1,5-mercuracyclooctane. Hg₂Si₄C₁₀H₂₈ (I) and of bis-(triphenylsilyl)mercury, (Ph₃Si)₂Hg (II), are reported. The structures have been determined from single-crystal X-ray data collected by counter methods. Both molecules crystalize in the space group P1 with one centrosymmetric molecule per unit cell. Each structure contains linear SiHgSi groups, with mercury-silicon distances of 2.490(4) Å in I and 2.503(4) Å II. In compound I the SiHgSi groups are linked by methylene bridges which form an eight member ring in the chair conformation. The cell dimensions for compound I are a 6.277(2), b 8.408(2), c 9.274(4) Å, α 92.75(3), β 94.79(3) and γ 100.14(2)° with R₁0.062 for 1809 observed reflections. The cell dimensions for compound II are a 9.999(4), b 11.727(8), c 7.654(5) Å, α 99.87(5), β 115.35(4) and γ 98.41(4)°, with R₁0.081 for 2394 observed reflections.     

An X-ray and 13C CP/MAS NMR study of C,C-linked bipyrazoles and bispyrazolylmethanes

4,4′-Methylene-bispyrazole (1) crystallizes in the P2₁/n space group with Z = 4, a = 5.4199(8) Å, b = 16.194(6) Å, c = 8.381(5) Å, β = 98.18(5)°. 4,4′-Methylene-bis (3,5-dimethylpyrazole) (2) crystallizes in the Pbca space group with Z = 8, a = 8.350(3) Å, b = 16.078(3) Å and c = 17.154(5) Å. Finally, 3,3′-bipyrazole (4) crystallizes in the P2₁/n space group with Z = 2, a = 5.465(2) Å, b = 5.491(3) Å, c = 10.058(4) Å and sol; = 92.88(2)°. The packing adopted by molecules 1 and 2 is related to the disposition of the pyrazole rings. In compound 4, all the molecules are joined to their neighbors by two double hydrogen bond systems forming zigzag chains. Using solid state ¹³C NMR spectroscopy, no dynamic proton transfer was observed in these crystals, and not on those of 3,5,3′,5′-tetramethyl-4,4′-bipyrazole (3) either.     

Stereochemically active lone pairs of electrons in subvalent main fourth-group compounds. The crystal and molecular structures of {η5-C5H5Co[P(OC2H5)2O]3}2MII (M = Sn,Pb)

The air-stable, mixed main group-transition metal, trinuclear sandwich oxygen tripod 2/1 complexes, {η⁵-C₅H₅Co[P(OC₂H₅)₂O]₃}₂M, (1, M = Sn): C₃₄H₇₀Co₂O₁₈P₆Sn, a 18.871(12), b 22.461(12), c 12.671(7) Å, β 92.53(5)°, monoclinic space group P2₁/a, d_calc 1.472 g cm⁻³, Z = 4, R = 9.5%: 2 (M = Pb): C₃₄H₇₀Co₂O₁₈P₆Pb, a 18.787(8), b 22.397(9), c 12.674(3) Å, β 92,01(3)°, monoclinic space group P2₁/a, d_calc 1.594 gcm⁻³, Z = 4, R = 7.2%, have been subjected to single crystal X-ray analysis. Both complexes show a stereochemically active lone pair at the metal and coordination to two tridentate η⁵-C₅H₅Co[P(OC₂H₅)₂O]₃ groups. The angles through the MO₆ units are CoMCo 149.04(14)° and 150.96(7)° for M = Sn and Pb, respectively. The tilting of the two tripod ligand moieties is reflected in the MO internuclear distances which range from 2.24(3) to 2.83 (3) Å for M-Sn and 2.40 (2) to 2.66(3) Å for M = Pb, differences of 0.59(3) and 0.26(3) Å, respectively. The average distances are 2.48(3) and 2.51(2) Å for 1 and 2 which are isostructural.     

New fluorochromatouranylates of alkali metals: Synthesis and structure

Four new fluorochromatouranylates, namely, K[UO₂(CrO₄)F] · 1.5H₂O (I), Rb[UO₂(CrO₄)F] · 1.5H₂O (II), Rb[UO₂(CrO₄)F] · 0.5H₂O (III), and Cs[UO₂(CrO₄)F] · 0.5H₂O (IV), have been synthesized, and their crystallographic characteristics have been determined. All the compounds crystallize in monoclinic system, space group P2₁/c, with the unit cell parameters a = 13.1744(5) Å, b = 9.4598(3) Å, c = 13.0710(4) Å, β = 103.746(1)°, Z = 4, R = 0.0235 (I); a = 13.5902(7) Å, b = 9.5022(4) Å, c = 13.2271(6) Å, β = 102.914(2)°, Z = 4, R = 0.0247 (II); a = 24.7724(8) Å, b = 12.6671(4) Å, c = 9.4464(3) Å, β = 97.661(1)°, Z = 8, R = 0.0448 (III); a = 25.725(1) Å, b = 12.8261(5) Å, c = 9.4929(4) β = 97.208(1)°, Z = 8 (IV). The pairs of compounds I and II and compounds III and IV are isostructural. Crystals of compounds I–III have been subjected to complete X-ray diffraction study. It has been established that the structures of compounds I–III are built of [UO₂(CrO₄)F] _n ^n? layers, which are parallel to the (100) plane and linked into a framework by alkali-metal cations located between layers, together with water molecules. The effect of topological and geometric isomerism on the structural features of 34 known uranyl compounds of the AT³M² crystallochemical group, to which the studied compounds I–III also belong, is discussed.     

The crystal structure of triphenyltin isothiocyanate

The crystal structure of Ph₃SnNCS has been determined by single crystal X-ray diffraction. The crystals are monoclinic, P2₁, a = 19.02(3), b = 11.67(2), c = 15.49(2)Å;, β = 95.64(10)°, Z = 8. The molecules are arranged in infinite zig-zag S…SnNCS…Sn&.sbnd; chains similar to those in Me₃SnNCS, but with slightly longer SnN, shorter SnS bonds, and almost planar SnC₃ units. Principal mean bond lengths and angles are: SnN, 2.22(5); NC, 1.17(8); CS, 1.58(7); SSn, 2.92(1); SnC, 2.09(3); CC, 1.38(2)Å; SnNCm 161(4); CSSn, 97(3); SSnN, 175(3) and CSnC, 119.8(1.5)°.     

Synthesis of 1,2-ethanediylbis(diphenyl-phosphonium)-PH,P′H′ hexachloromolybdate(III) I and nonachlorodimolybdate(III) II. The crystal structure of (dppeH2)3[MoCl6]2·12h2O

Two compounds of the formulae (dppeH₂)₃[MOCl₆]₂ ·12H₂O I and (dppeH₂)₃[Mo₂Cl₉]₂II are described. For compound I, which proved to be active in olefin epoxidation, the crystal structure was determined. The rose-pink crystals are triclinic, space group P$\text{1}$ with a = 13.715(9), b₃ = 14.686(7), c = 12.512(7) Å, α = 109.56(4), β = 97,98(4) and γ = 91.27(5)°, V = 2345 Å, D_m = 1.42 and D_c = 1.44 gcm^?3, Z = 1. Block-diagonal least squares refinement of the structure has led to a final value of the conventional R factor of 0.049 for the 3914 independent reflections with I > 3σ(I). Bond distances are in the range: MoCl 2.439(2)–2.469(2) Å, and PC 1.771(9)–1.806(8) Å.