Synthesis of two complexes of cadmium(II) iodide with benzenecarbothioamide (BCTA): Crystal and molecular structure of [Cd(BCTA)2I2]

The reaction between CdI₂ and benzenecarbothioamide (BCTA) in ethanol produces crystalline [Cd(BCTA)₂I₂] but in 1,2-dichloroethane it yields [Cd(BCTA)I₂] in powder form. [Cd(BCTA)₂I₂] has been characterized by X-ray crystallography, and both complexes have also been identified by infrared spectra in the solid phase, ¹H NMR, and electrical conductivity studies in solution. The crystals of [Cd(BCTA)₂I₂] are monoclinic, space group P2₁/c, with a = 747.6(1) pm, b = 1958.7(13) pm, c = 1363.6(6) pm, β = 110.307(3)° and Z = 4. Least-squares refinement of the structure based on 4260 observations led to final discrepancy indices of R = 0.043 and R_w = 0.054. The geometry around the cadmium atom is slightly distorted from the tetrahedral. The BCTA is coordinated through the sulphur atom: CdI(1) = 277.2(1) pm, CdI(2) = 272.6(1) pm, CdS(1) = 256.7(3) pm, CdS(2) = 257.5(2) pm. The electrical conductivity studies and NMR and IR spectra are consistent with the structure found for [Cd(BCTA)₂I₂] and suggest a dimeric trans symmetric tetrahedral structure with halogen bridging (C_2h) for [Cd(BCTA)I₂].     

The crystal structure of barium manganese(II) iron(III) fluoride BaMnFeF7

The crystal structure of the monoclinic compound BaMnFeF₇ has been determined: a = 553.2(1), b = 1098.0(2), c = 918.3(1) pm, β = 94.67(1)°, V = 555.9(3) × 10^?24 cm³, Z = 4. All atoms are in general positions of space group $\text{P2}{}_1\text{c}$, weighted R = 0.031, using 1771 independent single-crystal reflections with I > 2σ(I). The structure consists of edge-sharing dinuclear Mn₂F^6?₁₀ units (MnMn = 322.2 pm), linked via corners by intermediate FeF₆ octahedra, at which two cis ligands remain unbridged. The average distances in the distorted octahedra are MnF = 211.6 pm and FeF = 192.7 pm. The barium atoms are irregularly 12-coordinated with a mean distance BaF = 290.5 pm. The structure is discussed in relation to the trigonal weberite Na₂MnFeF₇ and others.     

Strukturchemie dreigliedriger brückenliganden : II. Molekülstruktur eines zweikernigen titan-komplexes mit phosphonium-bismethylid-brücken

Ti₂(OMe)₆[(CH₂)₂PMe₂]₂ crystallizes in the triclinic space group P$\text{1}$ with a 860(1), b 968(1), c 1448(3) pm, α 103.22(14), β 92.02(13) and γ 93.77(14)° Two halves, each of an independent molecule are within the asymmetric unit. The titanium atoms (TiTi 325.4 and 326.5 pm) are bridged by two methoxy groups and two dimethylphosphonium-bismethylide ligands, the latter being trans to each other. By two additional methoxy groups each titanium atom reaches approximate octahedral coordination. TiO (bridge) 205 pm, TiO (termial) 180 pm, TiC 225 pm (mean values). Adaptation of the bite width of the ylide ligands to the metal—metal distance essentially results from C_s configuration of the five membered Ti₂C₂P rings and from opening of the TiCP angles to 119.5°. General aspects of the geometry of phosphonium-bismethylide ligands are discussed.     

Alkyl- und arylkomplexe des iridiums und rhodiums : VIII. Ungewöhnlich hoher trans-einfluss des carbonylliganden. Molekülstrukturen von cis- und trans-Ir(2,4,6-Me3C6H2)(CO)(PPh3)2

The molecular structures of cis- and trans-Ir(2,4,6-Me₃C₆H₂)(CO)(PPh₃)₂ have been determined by X-ray diffraction methods. Crystals of cis-Ir-(2,4,6-Me₃C₆H₂)(CO)(PPh₃)₂ (A) are monoclinic (P2₁/c) with a 1311.0(3), b 1888.5(6), c 1589.7(5) pm, β 101.85(2)°, and Z = 4. The trans complex B likewise crystallizes in the monoclinic space group P2₁/c with four molecules per unit cell, the lattice parameters being a 981.2(4), b 1214.7(7), c 3579.8(17) pm, and β 102.29(3)°. Based on 2971 and 2883 intensity data, the structures have been refined by full-matrix least squares to R values of 0.051 and 0.059 for A and B, respectively. The molecular geometries may be described as square planar. In the case of the cis-isomer the coordination shows some degree of tetrahedral distortion as a result of steric crowding. IrP distances in B are 231.3(5) and 231.9(5) pm, while in A IrP trans to mesityl is 232.4(3) pm, but trans to CO 237.0(3) pm. The carbonyl ligand thus seems to exert an even stronger trans-influence on IrP than the aryl group. This effect is discussed in terms of dπdπ participation in the metal—phosphine linkage. A very close contact of 244 pm is observed between the central metal and one of the ortho-methyl hydrogens in A which may contribute to kinetic stabilization of the thermodynamically unfavoured cis-isomer.     

Strukturuntersuchungen an mono- und bis-alkoxy(triphenylsilyl)-carben-komplexen des rheniums

Steric and electronic influences on bond lengths and angles at the carbene carbon atoms of cis-Re₂(CO)₉C(OR)SiPh₃ (I: R = CH₃, II, R = C₂H₅) and cis,trans-Re₂(CO)₈[C(OEt)SiPh₃]₂ (III) are discussed based on their structural analyses. I (ReRe 305.2(1) pm; ReC(carbene) 209(2) pm) and II (two independent molecules; ReRe 305.0(3) and 305.2(4) pm; ReC (carbene) 208(5) and 210(5) pm) differ by the cis and trans positions of the alkyl groups at the partial C(carbene)O double bonds. The change in configuration affects the bond angles at the carbene carbon. In III the carbene ligands are bonded to different rhenium atoms; cis to one Re atom and trans to the other Re atom (ReRe bond 309.1(2) pm). The ReC(carbene length of the trans- carbene ligand is significantly shorter (185(3) pm) than that of the cis-carbene ligand (208(3) pm).     

Darstellung, eigenschaften und kristallstruktur von methylgalliumdiacetat CH3Ga(OOCCH3)2

Trimethylgallium reacts with acetic acid in a $\text{1}\text{2}$ molar ratio yielding methylgallium diacetate, CH₃Ga(OOCCH₃)_2? The structure is determined by vibrational spectroscopy and the crystal structure is described. Methylgallium diacetate crystallizes in the monoclinic space group P2₁/c with lattice constants a 776.5, b 1428.9, c 1406.3 pm, β 91.87° and eight formula units per cell. The monomers are linked together by acetate groups forming polymeric, waved layers. Besides the bridging acetate there are also “free” acetate groups coordinated at the distorted trigonal-bipyramidal coordinated Ga(1) atom. A second gallium atom Ga(2) is coordinated distorted tetrahedrally, the acetate groups bonded to Ga(2) being all bridging. The mean intermolecular distances are: GaC 194.6 pm, Ga(1)O_apical 215.3 pm, Ga(1)O_eq(bridge) 194.3 pm, Ga(1)O_eq(free) 187.3 pm, Ga(2)O 191.3 pm, CC 151.5 pm, CO 119.4 pm, CO 131.1 pm, CO 127.3 pm.     

Die kristallstruktur des trimethylbleiazids,Me3PbN3

Me₃PbN₃ crystallizes as colourless needles in the space group P3₁21 (or P3₂21) with a 664.6 ± 5 pm; c 1378 ± 1 pm; V 527.2 »³; Z = 3; d_c 2.781 g cm^?3. With 122 independent reflections (7 non-observed by I < o(I)) and anisotropic temperature factors for the lead atom the structure was refined to a conventional R-value (without hydrogen atoms) R = 0.042. Planar Me₃Pb groups are linked by linear N₃ groups in a 3₁ (or 3₂) screw, rendering the lead atoms an almost perfect trigonal bipyramidal coordination sphere (PbN 258 pm; PbC 225 pm). The Me₃Pb units are ordered in a skew conformation; since the lead atoms are positioned 65 pm away from the screw axes the packing of the methyl groups is not influenced (Pb·Pb 474 pm).     

A neutron powder diffraction study of the κ phase in the FeWC system

The crystal structure of the κ-carbide in the FeWC system has been refined from neutron powder diffraction data using the Rietveld profile analysis method. κ-(FeWC) is isostructural with κ-(CoWC); space group $\text{P6}{}_3\text{mmc}$; unit cell dimensions a = 7.7982(2)Å, c = 7.8298(4) Å. The structure refinement indicates $\text{Fe}\text{W}$ substitution at two of the tungsten sites, and 46% vacancies at one of the carbon sites. The composition corresponds to the formula Fe_3+xW_10?xC_4?y, with x = 0.57(3) and y = 0.46(1).     

The chemistry and the stereochemistry of poly(n-alkyliminoalanes) : III. The crystal and molecular structure of the adduct (HalN-i-Pr)6AlH3

The crystal and molecular structure of the adduct (HAlN-i-Pr)₆AlH₃ has been determined from single-crystal and three dimensional X-ray diffraction data collected by counter methods. The cage-type molecular structure consists of two six-membered rings, (AlN)₃, joined together by four adjacent transverse AlN bonds; the loss of two of these bonds allows the complexation of one alane molecule, with five-coordination of the aluminum (trigonal bipyramidal geometry), through two AlN bonds and two AlHAl bridge bonds. The AlN bond lengths range from 1.873 to 1.959 Å; the average AlH bond length is 1.50(1) Å for the four-coordinated aluminum atoms; the average distance of the two apical hydrogens from the five-coordinated aluminum atom is 1.92(5) Å. Colourless prismatic crystals of the compound have the following crystal data: triclinic space group P$\text{1}$; a = 17.13(2); b = 10.78(2); c = 10.20(2) Å; α = 124.3(4), β = 92.0(4), γ = 92.1(5); Z = 2; calculated density 1.157 g/cm³. The structure has been refined by block-matrix, least-squares methods using 4358 independent reflections to a standard unweighted R factor of 4.9%.     

The crystal structure of Mn(NO)3P(C6H5)3: The first x-ray analysis of a mononuclear metal trinitrosyl complex

The structure of Mn(NO)₃PPh₃ has been analyzed by single-crystal X-ray diffraction. It shows a tetrahedral geometry with essentially linear nitrosyl groups, and an eclipsed configuration around the MnP bond. Average distances and angles are: MnN 1.686(7) Å, MnP 2.315(2) Å, NO 1.165(10) Å, PC 1.815(4) Å, MnNO 177.2(7)°, PMnN 103.6(2)°, NMnN 114.7(4)°. Final R factor 7.3% for 2064 non-zero reflections. The structure of the five-coordinate nitrito complex Mn(NO)₂(ONO)(PEt₃)₂ is also mentioned briefly.     

Die konformation des μ-bis[tetracarbonylrhenium(I)]-bis-[tetracarbonyl(trithiocarbonato)rhenium(I)], eines überraschenden reaktionsproduktes bei der umsetzung von CF3Re(CO)5 mit CS2

The molecular structure of [(C₆H₅)₃P]₂Pd(C₃H₄) has been determined from three-dimensional X-ray diffraction data. The crystal belongs to the triclinic system, space group P$\text{1}$, with two formula units in a cell of dimensions: a = 19.475(2), b = 10.204(2), c = 18.341(2) Å, α = 108.46(2), β = 85.46(1), and γ = 118.80(1)°.One of the olefinic bonds of allene is coordinated to the palladium atom: PdC(1) = 2.118(9) and PdC(2) = 2.067(8) Å. The coordinated allene is no longer linear, the C(1)C(2)C(3) angle being 148.3(8)°. The C(1)C(2) distance is 1.401(11) Å, whereas the uncoordinated bond remains unchanged [C(2)C(3) = 1.304(12) Å]. The Pd, P(1), P(2), C(1) and C(2) atoms lie almost in the same plane.     

Molecular structures of (SiCl3)2CH2 and (SiCl3)2CCl2 as studied by electron diffraction

An electron diffraction analysis of the molecular structures of 1,1,1,3,3,3-hexachloro-1,3-disilapropane and octachloro-1,3-disilapropane has been carried out. Deviations from the staggered conformation are indicated. The data may be approximated by models with C₂ symmetry and a small tilt of the SiCl₃ groups. The main bond lengths (r_g) and bond angles obtained for (SiCl₃)₂ CH₂ are: SiCl, 202.7(4); SiC, 186.6(6); CH, 109.8(24) pm, ClSiCl, 107.9(1); SiCSi, 118.3(7)°; and for (SiCl₃)₂CCl₂: SiCl, 202.0(4); SiC, 190.2(9); CCl, 179.6(9) pm; ClSiCl, 109.5(1); SiCSi, 120.6(9); ClCCl, 110.9(16); SiCCl, 106.3(3)°.     

Struktur von [CPRu(C0)2]2 (Cp  η5-pentamethylcyclopentadienyl)

The molecular structure of di-μ-carbonyl-bis[carbonyl(η⁵-pentamethylcyclopentadienyl)ruthenium] (RuRu) has been determined by a single-crystal X-ray diffraction study (monoclinic, space group P2₁/n,a  979.90(9), b = 831.91(7), c = 1427.75(12) pm, β = 100.026(9)°, R = 0.018). In the solid state the complex exists solely as the trans-carbonyl bridged isomer. The RuRu bond length is 275.2(1) pm.     

The structure of the metallated iridium complex [(C8H12)Ir{P(OC6H3Me)(OC6H4Me)2} {P(OCH2)3CMe}]

The crystal structure of [(C₈H₁₂)$\text{Ir{P(OC}$₆H₃Me)(OC₆H₄Me)₂} {P(OCH₂)₃CMe}] has been determined. a 18.32, b 18.98, c 9.35 Å, U 3251 ų, Pn2_1^a, Z = 4, R = 0.048, 2541 observed data.The coordination about the iridium atom is distorted trigonal bipyramidal; the two phosphorus atoms are equatorial, the σ-bonded carbon is axial, and the bidentate cyclooctadiene is bonded axialequatorial. The IrC(axial) bonds are longer than the IrC(equatorial) bonds: 2.22, 2.26; 2.17, 2.19 Å. The IrC(σ) bond length is 2.19 Å, not significantly different from the formally π-bonded C to Ir distances. The IrP lengths of 2.201 and 2.240 Å and the PIrP angle of 108.7° are normal. The longer IrP bond is in the five-membered chelate ring. The inertness to substitution is discussed.     

Phase relations in the TlXTl2Se systems (X = Cl,Br, I) and the crystal structure of Tl5Se2I

Each of the quasibinary systems TlClTl₂Se, TlBrTl₂Se, and TlITl₂Se contains a region of solid solution up to 18 mole% Tl₂Se, which decomposes peritectically. The mixed crystals can be explained by a statistical substitution of Se by two I atoms on the fourfold sites of the Tl₂Se lattice. Compounds of the type Tl₅Se₂X were derived by complete substitution. Crystals of Tl₅Se₂I, suitable for a crystal structure determination, were grown by the Bridgman technique. Tl₅Se₂I is tetragonal, $\text{I4}\text{mcm}\text{; a = 866.3}\text{pm}\text{, c = 1346.3}\text{pm}\text{, Z = 4}$. The structure is an ordered variation of the In₅Bi₃ structure and isopuntal to the Cr₅B₃ type. The structure is formed basically by layers of Tl₂Se, in which strings of TlI are introduced. The compounds Tl₅Se₂Br (a = 861.1 pm, c = 1292.2 pm) and Tl₅Se₂Cl (a = 856.5 pm, c = 1273.3 pm) have probably very similar structures. A tendency for immiscibility in the TlXTl₂Se systems is shown by the existence of a miscibility gap in the system TlClTl₂Se and by the endothermic enthalpies of mixing in the system TlBrTl₂Se. In the TlITl₂Se system the compound Tl₆Se₄I system was encountered.     

The phase diagrams of Ag2XAgY (X = S,Se, Te; Y = Cl,Br, I): Mixtures and the structure of Ag5Te2Cl

The phase diagrams of Ag₂SAgI, Ag₂SeAgI, Ag₂TeAgI, Ag₂TeAgBr, and Ag₂TeAgCl were investigated. The system Ag₂S-AgI shows two broad regions of solid solution which are based on the structure of the high-temperature phases of the constituent compounds. The high-temperature modification of Ag₃SI is part of one of these regions. The system Ag₂SeAgI resembles the system Ag₂TeAgI; both contain limited regions of terminal solid solutions. The AgI-based solid solutions decompose peritectically. In the system Ag₂TeAgBr a compound Ag₃TeBr was found. Ag₃TeBr undergoes a phase transition at 590 ± 20 K. The low-temperature form has hexagonal symmetry with the lattice parameters a = 748.8(1) pm and c = 4357.6(6) pm. The compound Ag₅Te₂Cl was found in the Ag₂TeAgCl system. In both systems a restricted terminal solid solution, based on the high-temperature form of Ag₂Te, was observed. Ag₅Te₂Cl has a reversible phase transformation at 329 ± 3 K with ΔH_tr = 9.82 ± 0.4 kJ mole^?1. β-Ag₅TeCl, the low-temperature form probably has the space group $\text{P2}{}_{\mathrm{<mtext>1</mtext><mtext>n</mtext>}}\text{, a = 1365.5(1), b = 1386.1(1), c = 764.23(2)}$, β = 90.201(1)°, and Z = 4, α-Ag₅Te₂Cl has the space group $\text{I4}{}_{\mathrm{mcm}}$ with a = 975.5(3), c = 783.0(1) pm, and Z = 4. The anion sublattice is built of octahedra, which share all their vertices with neighboring octahedra. The Ag⁺ ions are distributed over octahedral holes of this network. The phase is similar in behavior to Ag₈GeTe₆ and may be a silver-ion conductor.     

The structure of (dichloro) (DI-μ-acetato)(bis-triphenyl phosphine) dimolybdenum(II)

The title compound was obtained in crystalline form suitable for X-ray structure determination. It forms crystals in the monoclinic space group P2₁/c with two centrosymmetric molecules in a unit cell of dimensions, a = 10.888(1) Å, b = 10.182(2) Å, c = 17.929(4) Å, β = 104.33(1)°. The central Mo₂Cl₂(O₂C)₂P₂ core has effectively C_2h-symmetry with the following principal dimensions: MoMo = 2.091(1) Å, MoCl = 2.405 Å, MoP = 2.566(2) Å, MoO(av.) = 2.103[4] Å, MoMoP = 104.38(7)°, and MoMoCl = 116.23(8)°.     

The molecular structure of p-bis(trimethylsilyl)-benzene from gas phase electron diffraction

Nearly regular tetrahedral silicon bond configuration and a considerably distorted ring characterize the p-bis(trimethylsilyl)benzene molecular geometry according to an electron diffraction study. The SiC_methyl bond is longer than the SiC_phenyl bond, in agreement with expectation but contrary to an X-ray diffraction determination. The extent of ring deformation is consistent with the electropositive character of the trimethylsilyl substituent and with the structural variations in other para-disubstituted benzene derivatives. The electron diffraction data are consistent with either free rotation around the SiC_phenyl bonds or with a rotamer deviating by about 15° from the eclipsed form. The following bond lengths (r_g, pm) and bond angles (°) have been determined with parenthesized estimated total errors: (CC)_mean 140.8(3), (C_ipso)(C_orthoC_meta) 1.6(7), (SiC)_mean 188.0(4), (SiC_methyl)(SiC_phenyl) 3.3(7), (CH)_methyl 111.3(3), CC_ipsoC 115.7(6), and C_phenylSiC_methyl 109.2(4).     

Fluorenylsilane : III. Über die umsetzung von 9-fluorenyl-tris(trimethylsilyl)silan mit chlor

9-Fluorenyltris(trimethylsilyl)silane (A) reacts with chlorine in CCl₄ to give dichloro-9-fluorenyltrimethylsilylsilane (B) in good yield. B is characterized spectroscopically and by X-ray structure analysis; it crystallizes in the triclinic space group P$\text{1}$ with a 950(2), b 1367(3), c 1138(2) pm, α 137.5(1), β 109.9(2), γ 89.8(2)°. The conformation of B is staggered with approximate C_s-symmetry; C(9)Si 187.6(5), SiSi 233.2(4), SiCl 207.1(3) and 205.3(3) pm.     

Ligandeneigenschaften von Fe3(CO)9(μ3-S)(μ3-ER) (R = alkyl,aryl; E = P,As)

The clusters Fe₃(CO)₉(μ₃-S)(μ₃-ER) (E = P, As; R = Alkyl, Aryl) react with (CO)₅M · THF (M = Cr, W) to give the violet crystalline adducts Fe₃(CO)₉(μ₃-SM(CO)₅)(μ₃-ER). Spectroscopic data and X-ray structure analyses show that adduct formation occurs via the triply bridging sulfur (SCr 242.8(5), SW 254.7(6) pm).