Crystal and molecular structure of chloro-bis(1,2-cyclohexanedione-dioxime)triphenylphosphinecobalt(III)

The structure of chloro-bis(1,2-cyclohexanedionediaxwte)triphenylphosphinecobalt(III) [Co(NioxH)₂PPh₃Cl] was determined by X-ray diffraction analysis. The crystal is monoclinic, a = 17.049(3), b = 15.223(3), c = 11.032(3) å, Β = 87.44(2)?, R(hkl) = 0.068 for 2739 reflections with I ≥2Σ(I). The structure is molecular. In the octahedral complex, the cobalt(III) atom is coordinated by two NioxH residues (av Co-N = 1.876 å), the phosphorus atom (Co-P = 2.307 å), and the Cl^- union (Co-Cl = 2.260 å). In the crystal, there are weak intermolecular interactions C-H…Cl and C-H…O.     

Crystal and molecular structure at −35°C of (π-cyclobutadiene)dicobalt hexacarbonyl

The structure of cyclobutadienedicobalt hexacarbonyl, (C₄H₄)Co₂(CO)₆, has been determined by single crystal X-ray diffraction techniques with data gathered at ?35°C by counter methods. Crystals form as red prisms in orthorhombic space group Pnma, with lattice parameters (at ?35°C) a = 12.916(3), b = 10.353(2) and c = 9.118(3) Å for a unit cell with four molecules of (C₄H₄)Co₂(CO)₆. The molecules have rigorous C_s symmetry, with a π-cyclobutadiene ring bound to the Co atom of a Co(CO)₂ moiety which, in turn, is linked to a Co(CO)₄ fragment through the metal atoms. Apparently to decrease repulsion between the cyclobutadiene ring and the bulky Co(CO)₄ group, the four-membered ring is tilted, and as a consequence the CoC₄H₄ interaction is unsymmetrical (CoC(ring) = 1.980(3) to 2.048(4) Å). Full-matrix least-squares refinement of the structure has converged with a R index (on |F|) of 0.027 for 1539 symmetry-independent reflections with I_o > 2.0σ(I_o) within the Mo-K_α shell defined by 4° < 2θ < 60°.     

Basische metalle : IX. Synthese und kristallstruktur von C5H5Co(PMe3)CS2. Reaktionen zu zweikernkomplexen mit Co(SCS)Cr- und Co(SCS)Mn-Brückenbindungen

C₅H₅Co(PMe₃)CS₂ (IV) is formed in practically quantitative yield in the reaction of C₅H₅Co(PMe₃)₂ (I) or the heterobinuclear complex C₅H₅(PMe₃)Co(CO)₂Mn(CO)C₅H₄Me (III) with CS₂. The crystal structure shows that the carbon disulfide bonds as a dihapto ligand through the carbon and one sulfur atom (S(2)) (CoC = 1.89, CoS(2) = 2.24 Å, S(2)CS(1) = 141.2°). The two CS bond lengths in IV (CS(2) = 1.68, CS(1) =1.60 Å) are greater than in free CS₂ (1.554Å) which is in agreement with the strong π-acceptor character of h²-CS₂ as shown in the spectroscopic data. IV reacts with Cr(CO)₅THF and C₅H₅Mn(CO)₂THF to give the complexes C₅H₅(PMe₃)Co(SCS)Cr(CO)₅ (V) and C₅H₅(PMe₃)Co(SCS)Mn(CO)₂C₅H₅ (VI) respectively, in which the sulfur atom S(1) that is not bound to cobalt coordinates to the 16-electron fragments Cr(CO)₅ and Mn(CO)₂C₅H₅. The spectroscopic data of IV, V and VI are discussed.     

Reactions of tetracarbonylcobaltate(-I) with chlorosilanes in ether solvents

The reactions of NaCo(CO)₄ with Me_nSiCl_4?n (n = 0–3) in diethylether (Et₂O) and in tetrahydrofuran (THF) have been studied. Three distinct reaction pathways were recognised which depend on the acidity of the chlorosilane and basicity of solvent. Attack at the silicon centre via the Co atom of Co(CO)₄^? leads to formation of a SiCo bond; reaction involving a CO ligand of Co(CO)₄^? gives clusters R₃SiOCCo₃(CO)₉; and chlorosilane induced attack of Co(CO)₄^? on the solvent gives products derived from THF molecules.     

Carbonylcobalt(I) complexes. The crystal and molecular structure of [Co(CO)(dppm)2]ClO4

New anionic carbonylcobalt(I) complexes [X₂Co(CO)₂(PPh₃)](PR₄) (X=Cl, PR₄ = PBzPh₃ (I); X = Br, PR₄ = PEtPh₃ (II)) have been prepared by reduction of the cobalt(II) halides with NaBH₄ in the presence of PPh₃ and the phosphonium salt PR₄X. Cleavage of halide bridges in dimeric or polymeric [XCo(PPh₃)₂]_n and [XCo(PPh₃)]_n gives the neutral dicarbonyl derivatives XCo(CO)₂PPh₃)₂. Treatment of ClCo(CO)₂(PPh₃)₂ with alkylating agents gives the known σ- and η- organocobalt(I) derivatives, and reactions with TIClO₄ in the presence of various amounts of different mono- and bi-dentate phosphines give the cationic tricarbonyl [Co(CO)₃(PPh₃)₂]⁺, dicarbonyl [Co(CO)₂(PMePh₂)₃]⁺ and monocarbonyl [Co(CO)L₄]⁺ complexes (L₄ = 4P(OMe)₃, 2 dppe and 2dppm). The dppm complex crystallizes in the monoclinic space group P2₁/c with a 17.895(6), b 10.751(2), c 24.687(4) Å, β 98.92(1)°, and D_calc 1.35 g cm⁻³ for Z = 4. A final R value of 0.077 ( R_w = 0.061), based on 2656 observed reflections, was obtained. The cobalt atom exhibits a distorted trigonal bipyramidal geometry. The perchlorate anion is severely disordered or freely rotating.     

Cymantrenecarboxylate complexes of nickel(II) and cobalt(II)

Reactions of cymantrenecarboxylic acid (CO)₃MnC₅H₄COOH (CymCOOH) with Ni(II) and Co(II) pivalates in boiling THF followed by extraction of the products with diethyl ether or benzene and treatment with triphenylphosphine gave the binuclear complexes LM(CymCOO)₄ML (M = Ni (I) and Co (II); L = PPh₃). Treatment of the benzene extract of the intermediate cobalt cymantrenecarboxylate with 2,6-lutidine (L’) yielded the trinuclear complex L’Co(CymCOO)₃Co(CymCOO)₃CoL’ (III). Complex I is antiferromagnetic; μ_eff decreases from 3.7 to 0.9 μ_B in a temperature range from 300 to 2 K. Structures I-III were identified using X-ray diffraction. The frameworks of complexes I and II are like Chinese lanterns, having four carboxylate bridges and axial ligands L (Ni-P, 2.358(1) Å; Co-P, 2.412(2) Å). The metal atoms are not bonded to each other (Ni…Ni, 2.7583(9) Å; Co…Co, 2808 (2) Å). In complex III, either terminal Co atom is coordinated to one ligand L’ (Co-N, 2.059(2) Å). The Co atoms form a linear chain showing no M-M bonds (Co…Co, 3.346(1) Å), in which either terminal Co atom is linked with the central Co atom by three carboxylate bridges (on average, Co_centr-O, 2.164 Å; CO_term-O, 2.094 Å). In one of three carboxylate groups, only one carboxylate O atom serves as a bridge, while the other is bonded to the terminal Co atom only (Co_term-O, 2.094 and 2.389 Å); so this carboxylate group is a bridging and chelating ligand.     

Crystal structure of (Et4N) [(µ-H)Fe3(µ3-Se)(CO)9]

The crystal structure of (Et₄N)[(μ-H)Fe₃(μ₃-Se)(CO)₉] is determined;the crystals are monoclinic, a = 11.172(2), b =32.332(5), c =13.552(3) ?, μ =91.86(2)‡, V _cell =4893(2) ? ³, space group P2₁/n, Z =8, d _calc =1.710 g/cm ³, CAD-4 diffractometer, MoK_α radiation;the total number of data collected 4395,including 4086 independent reflections(R_int =0.0701), R(F) =0.0566, wR(F ²) =0.1202 for 1963 F _hkl > 4Σ(F). The data were corrected for the 37.8% linear drop of intensities of the control reflections due to crystal decay. The Fe-H bond lengths are 1.5(1)-1.72(9) ?. As in the case of three-osmium clusters,the presence of the Μ-H ligand leads to a lengthening of the Fe-Fe bond by approximately 0.1 ? and to push-away of the equatorial carbonyl ligands leading to an increase in the FeFeC angle by approximately 5–10‡, whereas the axial CO and (Μ ₃-Se) remain unchanged.     

Reactivity of main-group—transition-metal bonds : VI. the kinetics of iodination of tetracarbonyl(trimethylstannyl)cobalt and pentacarbonyl(trimethylstannyl)rhenium

The kinetics of the iodine cleavage of the SnCo bond in [Me₃SnCo(CO)₄ ] and of the SnRe bond in [Me₃SnRe(CO)₅] have been measured. The order of rates of cleavage of the SnM bond in the compounds [Me₃SnM(CO)_x(cp)_y] (M = Mn, Re, x = 5, y = 0;M = Co, x = 4, y = 0; M = Cr, Mo, W, x = 3, y = 1; M = Fe, x = 2, y = 1; cp = η-cyclopentadienyl) indicates that the main factors determining reactivity towards iodine are the size of the metal atom (M) and the shielding of it by the other ligands.     

Synthese und Struktur von [(Ph3PAu)6Co(CO)2](PF6) und [(Ph3PAu)7Co(CO)2](PF6)2

Synthesis and Structure of [(Ph₃PAu)₆Co(CO)₂](PF₆) and [(Ph₃PAu)₇Co(CO)₂](PF₆)₂ By the reaction of (Ph₃PAu)₄Co[(CO)₃]⁺ with OH^? in the presence of excess Ph₃PAuCl the larger cluster cations [(Ph₃PAu)₆Co(CO)₂]⁺ ( 1 ) and [(Ph₃PAu)₇Co(CO)₂]²⁺ ( 2 ) can be built up with 1 being the main product. 1 crystallizes with PF^?₆ as counterion in the monoclinic space group C2/c with a = 3008.3(6); b = 1339.1(2); c = 2909.4(6) pm; β = 103.08(1)°; Z = 4. The inner core of the cluster cation 1 with the symmetry C₂ has the form of a bicapped trigonal bipyramid with the heteroatom in equatorial position, and distances Au? Au between 280.4(1) and 288.4(1) pm and Co? Au between 254.9(1) and 257.1(2) pm. 2 · (PF₆)₂ crystallizes in the triclinic space group P1 with a = 2155.7(1); b = 1720.6(1); c = 3543.6(1) pm; α = 91.89(1)°; β = 97.51(1); γ = 89.92(1)°; Z = 4. The unit cell contains two symmetry independent cluster cations 2 of about the same geometry. The cluster skeleton Au₇Co can be described as fragment of an icosahedron formed by seven gold atoms with the Co atom in its center. The Au? Au distances range from 274.8(3) to 332.6(3) pm, and the Co? Au distances are 256.8(6) to 264.7(5) pm. The bonding in 1 and 2 is discussed.     

Chemical bonding in “early–late” transition metal complexes [(H2N)3M–M′(CO)4] (M = Ti, Zr, Hf; M′ = Co, Rh, Ir)

Quantum chemical DFT calculations at the BP86/TZ2P level have been carried out for the complex [HSi(SiH₂NH)₃Ti–Co(CO)₄], which is a model for the experimentally observed compound [MeSi{SiMe₂N(4-MeC₆H₄)}₃Ti–Co(CO)₄] and for the series of model systems [(H₂N)₃M–M′(CO)₄] (M = Ti, Zr, Hf; M′ = Co, Rh, Ir). The Ti–Co bond in [HSi(SiH₂NH)₃Ti–Co(CO)₄] has a theoretically predicted BDE of D _e = 59.3 kcal/mol. The bonding analysis suggests that the titanium atom carries a large positive charge, while the cobalt atom is nearly neutral. The covalent and electrostatic contributions to the Ti–Co attraction have similar strength. The Ti–Co bond can be classified as a polar single bond, which has only little π contribution. Calculations of the model compound (H₂N)₃Ti–Co(CO)₄ show that the rotation of the amino groups has a very large influence on the length and on the strength of the Ti–Co bond. The M–M′ bond in the series [(H₂N)₃M–M′(CO)₄] becomes clearly stronger with Ti < Zr < Hf, while the differences between the bond strengths due to change of the atoms M′ are much smaller. The strongest M–M′ bond is predicted for [(H₂N)₃Hf–Ir(CO)₄].     

Crystal and molecular structure of the volatile mixed-ligand complex Zn(S2CN(i-C4H9)2)2Phen

The crystal and molecular structure of the mixed-ligand complex Zn(S₂CN(i-C₄H₉)₂)₂Phen was determined by single-crystal X-ray diffractometry (Syntex P2₁ diffractometer, CuK_α radiation, 1738 F(hkl),R = 0.036). The crystals are triclinic, a =18.564(4), b =10.487(1), c =17.505(4) å, α = 84.04(2), Β =94.88(2), γ =90.87(2)?;V =3377(1) å ³, Z = 4, d_calc = 1.287 g/cm³, space group C-1. The structure consists of monomeric molecules in which the zinc atom has a distorted octahedral environment (4S+2N).     

Cobalt(II) perchlorate,tetrafluoroborate, nitrate and sulphate complexes with 4,6-dimethylpyrimidine-2(1H)-thione

Contrary to earlier reports in which no adducts of Co(II) metal ion with 4,6-dimethylpyrimidine-2(1H)-thione(HL) could be isolated starting from Co(ClO₄)₂ · 6H₂O, we now report bis- and tris-ligand Co(II) complexes of the type [Co(HL)₂(H₂O)₂]X₂ · H₂O (X = ClO₄, BF₄), [Co(HL)₂NO₃]NO₃, [Co(HL)₂SO₄] · 0.5H₂O and [Co(HL)₃]X₂ · 0.5H₂O (X = ClO₄, BF₄). They have been synthesized by refluxing 2:1 and 3:1 mixtures of HL and CoX₂ · nH₂O in ethanol-triethyl orthoformate. We also describe new Co(HL)₂X₂ · nH₂O complexes in which for X₂ = ClBr, ClI and BrI, n = 2; for X₂ = I₂, n = 1 and for X₂ = (SCN)₂, n = 0. Structural characterization of the complex species is made from electronic and vibrational spectra, magnetic susceptibility measurements in the solid state and conductivity measurements in DMF solution. The magnetic and electronic spectral data together with ligand-field parameters suggest a pseudo-octahedral environment for all the Co(II) complexes, with the exception of Co(HL)₂SO₄ · 0.5H₂O in which the Co(II) ion appears to be pentacoordinated. The IR spectra are consistent with a coordination involving N,S-chelation of the ligand through the non-protonated ring nitrogen atom and the exocyclic sulphur atom.     

Paramagnetic carbonyl cobalt(II) complexes. Molecular structure of bromocarbonyl-1,1,1-tris(diphenylphosphinomethyl)ethanecobalt(II) tetraphenylborate

Carbon monoxide or cyclohexyl isonitrile (L) react with the dinuclear five-coordinated derivatives of 1,1,1-tris(diphenylphosphinomethyl)ethane, (triphos), [(triphos)Co(μ-X)₂Co(triphos)](BPh₄)₂ (X = halide) to give complexes of formula [(triphos)Co(L)X]BPh₄. The latter are rare examples of paramagnetic cobalt(II) carbonyl complexes. The molecular structure of [(triphos)Co(CO)Br]BPh₄ has been determined from counter diffraction data. The crystals are monoclinic, space group P2₁/a with cell dimensions a 20.225(8), b 20.664(9), c 13.301(5); β 97.24(5)°, D_c = 1.338 g cm^?3 for Z = 4. Full-matrix least squares refinement led to the conventional R factor of 0.057 for 3648 observed reflections. The molecular structure consists of five-coordinate [(triphos)Co(CO)Br]⁺ cations of intermediate geometry and BPh^?₄ anions.     

Cationic cobalt(I) carbonyl complexes containing secondary or tertiary phosphines. A direct synthesis from cobalt(II) salts

Cobalt(I) carbonyl complexes of formula [Co(CO)_n(P)_5?n]ClO₄ (n = 1, 2, 3; P = secondary or tertiary phosphine) have been prepared by reaction of CO under ambient conditions with Co(ClO₄)₂ · 6H₂O and phosphine in isopropyl alcohol. The chemical and spectroscopic properties of these complexes are described and the stoichiometry and mechanism of the carbonylation reaction discussed.     

Synthesis and crystal structure of tris(ethylenediamine)cobalt(III) bis(tetrachloroaurate(III)) chloride

The binary complex salt [Co(N₂C₂H₈)₃][AuCl₄]₂Cl has been synthesized. Its crystal structure has been determined. Crystal data for C₆H₂₄N₆Cl₉AuCo: a = 20.8976(14) Å, b = 14.4773(9) Å, c = 7.9944(5) Å; β = 110.809(2)°; V = 2260.9(3) ų, space group C2/c, Z = 4, d _calc = 2.798 g/cm³. The plane square environment of the gold atom of the complex anion is completed to a tetragonal pyramid by the chlorine atom of the neighboring complex anion (Au…Cl 3.538 Å). The structure is layered. Layers of complex cations and complex anions alternate along the X axis.     

Crystal and molecular structure of the monoclinic modification of Mn(S2CO-i-C3H7)2(2,2’-bipy)

The crystal and molecular structure of modification II of the Mn(S₂CO-i-C₃H₇)₂(2,2’-Bipy) complex was determined from X-ray diffraction data (“Syntex P2₁” diffractometer, CuK_α radiation, 1603 F(hkl), R = 0.0446). The crystals are monoclinic,a = 23350(3),b = 9.325(1),c = 22.030(2) å, Β = 106.98(1)?,V = 4587.7 å³, Z =8, d _calc = 1.394 g/cm³, space group C2/c. The structure consists of monomeric molecules in which the manganese atom has a distorted octahedral environment (4S + 2N). The orthorhombic and monoclinic modifications of the complex are compared with respect to the molecular geometry and packing.     

Crystal structure of kuznetsovite Hg3(AsO4)Cl

The crystal structure of a rare supergene mineral kuznetsovite Hg₃(As0₄)Cl, previously determined from powder data, is refined (space group P2₁3, a = 8.379(3) å, V = 588.3(4) å⁰³, Z = 4, d_calc = 8.763 glcm³, 3.44 < θ < 24.96?, 563 I_hkl(msd)/211 I_hkl(indep), R₁ = 0.0997, wR₂ = 0.2515). It is formed from the Cl^? and (AsO₄)^3- anions (As-O 1.74(3) and 1.79(1) å) and the trigonal cations Hg ₃ ⁴⁺ (Hg-Hg 2.675(5) å, HgHgHg 60?). The coordination polyhedron around each mercury atom involves two mercury atoms, two oxygen atoms at short Hg-0 distances (2.17(3) and 2.28(3) å, < OHgO 94.3(13)?), and more remote oxygen and chlorine atoms (Hg-0 2.601(6) å, Hg-Cl 2.838(9) å). The polyhedron is irregular and close to a trigonal antiprism. The Hg₃ triangles alternate with AsO₄ tetrahedra along each coordinate axis. Taking into consideration only short Hg-0 bonds (2.17(3) and 2.28(3) å), one can isolate a framework with chlorine ions lying in the cavities.     

Crystal and molecular structure of the mixed-ligand complex Zn[S2CN(CH3)2]2Phen

The crystal and molecular structure of the mixed-ligand complex Zn[S₂CN(CH₃)₂]₂Phen is determined by single crystal X-ray diffractometry (CAD-4 diffractometer, MoK_α radiation, 3347 F(hkl), R = 0.0385). The crystals are monoclinic, a =13.340(3), b =13.827(3), c =24.698(5) å, Β =102.58(3)? V = 4446(2) å ³, Z = 8, d_calc = 1.452 g/cm³ , space group C2/c. The structure consists of monomeric molecules in which the zinc atom has a distorted octahedral environment (4S+2N). The molecular packing in the crystal involves dimers related by the 2 rotation axis and forming continuous chains along the c axis.     

Cluster synthesis by photolysis of R3PAuN3 IV. Synthesis and structure of [(Ph3PAu)4Mn(CO)4]PF6

Photolysis of R₃PAuN₃ in the presence of Mn₂(CO)₁₀ yields the cationic cluster compounds [(Ph₃PAu)₄Mn(CO)₄]⁺ (1) and [(Ph₃PAu)₆Mn(CO)₃]⁺ (2), which can be separated by column chromatography. Compound 1 crystallizes from CH₂Cl₂-diisopropylether after addition of PF₆⁻ as 1 · PF₆· 0.5CH₂Cl₂ in the triclinic space group P1&#x0304; with a = 1709.8(6) pm, b = 2017.3(7) pm, c = 1180.3(7) pm, α = 106.42(3)°, β = 98.81(4)°, γ = 102.82(4)°, V = 3704.9 × 10⁶ pm³, Z = 2. The central unit of 1 is a trigonal bipyramid Au₄Mn with the manganese atom in equatorial position. The AuAu distances are in the range 277.3 to 292.2 pm. The manganese atom forms two short bonds of 263.3 and 264.0 pm to the axial gold atoms and two longer bonds of 272.3 and 273.3 pm to the equatorial neighbors. A d²sp³ hybridization can be assumed for the manganese atom. Four of the orbitals are used for the MnCO σ-bonds. The remaining two are then pointing approximately to the center of the Au₃ triangular faces.