CO replacement in the tetrahedrane cluster MeC(O)CCo3(CO)9 by the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-l,3-dione (bpcd): Diphosphine ligand isomerization and X-ray structure of the bridged cluster MeC(O)CCo3(CO)7(bpcd)

The tricobalt cluster MeC(O)CCo₃(CO)₉ reacts with the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-l,3-dione (bpcd) in the presence of added Me₃NO to furnish the disubstituted cluster MeC(O)CCo₃(CO)₇(bpcd) in good yield. MeC(O)CCo₃(CO)₇(bpcd) has been characterized in solution by IR and NMR (¹H and ³¹P) spectroscopies, and the solid-state structure determined by X-ray crystallography. MeC(O)CCo₃(CO)₇(bpcd) crystallizes in the monoclinic space group P2₁/c, a=14.8421(8), b=16.6162(9), c=14.9363(8) ?, β=99.705(1)°, V=3630.9(3) ?³, Z=4, D _cacl=1.632 Mg/m³; R=0.0288, R _w=0.0683 for 8618 observed reflections with I > 2σ(I). The bridging of adjacent cobalt atoms by the bpcd ligand in MeC(O)CCo₃(CO)₇(bpcd) is crystallographically established, and the facile isomerization of the bridging bpcd to the chelating isomer at low temperature is confirmed by VT ³¹P NMR measurements.     

Syntheses and X-ray structures of the bridging and chelating isomers of Os3(CO)10(dmpe)

The substitution chemistry of the activated clusters Os₃(CO)₁₀(MeCN)₂ (1) and Os₃(CO)₁₀(1,5-cod) (2) has been investigated with the bidentate ligand 1,2-bis(dimethylphosphino)ethane (dmpe). Both starting clusters react rapidly with dmpe at room temperature to give the corresponding substitution product Os₃(CO)₁₀(dmpe) (3), whose isomeric composition is shown to depend on the nature of the starting cluster. Whereas the bridged cluster 1,2-Os₃(CO)₁₀(dmpe) (3b) was formed almost exclusively upon reaction with Os₃(CO)₁₀(MeCN)₂, a near statistical mixture of bridging (3b) and chelating (3c) isomers of Os₃(CO)₁₀(dmpe) was found in the reaction employing Os₃(CO)₁₀(1,5-cod). Both dmpe isomers have been characterized in solution by 3iP NMR spectroscopy and their solid-state structures established by X-ray crystallography. The bridged cluster 1,2-Os₃(CO)₁₀(dmpe) crystallizes in the monoclinic space group P2₁/n, a = 9.867(2) Å, b = 17.081(3) Å, c = 14.198(2) Å, β = 95.902(3)°, V = 2380.4(6) ų, Z = 4, and d _calc = 2.793 Mg/m³; R = 0.0435, R _w = 0.0466 for 3519 reflections with I > 2σ(I). The chelated cluster 1,1-Os₃(CO)₁₀(dmpe) crystallizes in the orthorhombic space group C222(1), a = 8.329(3) Å, b = 19.028(6) Å, c = 15.008(5) Å, V = 2379(1) ų, Z = 4, and d _calc = 2.795 Mg/m³; R = 0.0390, R _w = 0.0718 for 2360 reflections with I > 2σ(I).     

Ligand-induced polyhedral opening in the mixed-metal cluster MeCCo2NiCp(CO)6 by 4,5-Bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd): X-ray structure of Co2NiCp(CO)4[μ2,η2,η1-C(Me)C=C(PPh2)C(O)CH2C(O)](μ2-PPh2)

The mixed-metal cluster MeCCo₂NiCp(CO)₆ (1) reacts with the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) in refluxing CH₂Cl₂ to afford the disubstituted cluster MeCCo₂NiCp(CO)₄(bpcd) (2), which exists as a 1:1 mixture of bridging and chelating bpcd isomers. VT ³¹P NMR spectroscopy confirms that the two bpcd isomers do not interconvert in solution over the temperature range of 182–298 K. Thermolysis of cluster 2 leads to bpcd/cluster activation and formation of the phosphido-bridged cluster Co₂NiCp(CO)₄[μ₂,η²,η¹-C(Me)C=C(PPh₂)C(O)CH₂C(O)](μ₂-PPh₂) (3). The ligand-induced polyhedral expansion that accompanies the formation of the title cluster was established by X-ray diffraction analysis. Co₂NiCp(CO)₄[μ₂,η²,η¹-C(Me)C=C(PPh₂)C(O)CH₂C(O)](μ₂-PPh₂) crystallizes in the triclinic space group P-1, a=9.679(2), b=11.691(2), c=16.653(3) ?, α=85.849(3)°, β=85.456(4)°, γ=66.453(3)°, V=1720.3(6) A³, Z=2, D _cacl=1.632 Mg/m³; R=0.0874, R _w=0.1998 for 7053 observed reflections with I > 2σ(I).     

Ligand substitution in the halo-bridged diruthenium compound [Ru(CO)3Cl2]2 by 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd). Synthesis, spectral properties, and X-ray diffraction structures of cis(CO), trans(Cl)-RuCl2(CO)2 (bpcd) and cis(CO)-RuCl[C(O)Et](CO)2(bpcd)

The reaction between 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) and the chlorobridged diruthenium complex [Ru(CO)₃Cl₂]₂ (1) proceeds readily at room temperature in CH₂Cl₂ to give the new ruthenium compounds cis(CO),trans(Cl)-RuCl₂(CO)₂(bpcd) (2) and cis(CO)-RuCl[C(O)Et](CO)₂(bpcd) (3) as the major and minor products, respectively. Compound 2 was isolated and fully characterized in solution, and the molecular structure was established by X-ray diffraction analysis. cis(CO),trans(Cl)-RuCl₂(CO)₂(bpcd) crystallizes in the triclinic space P-1, a = 9.931(5) Å, b = 12.093(7) Å, c = 13.529(7) Å, α = 72.886(9)°, β = 74.739(9)°, γ = 76.851(9)°, V = 1478.2(1) ų, Z = 2, and d _calc = 1.556 mg/m³; R = 0.0841, R _w = 0.1880 for 4137 reflections with I > 2σ(I). The chlorine atoms in 2 adopt a trans geometry at the octahedral ruthenium center, with the two CO groups exhibiting a cis orientation and trans to the bpcd ligand. cis(CO)–RuCl[C(O)Et](CO)₂(bpcd) crystallizes as two independent molecules in the unit cell in the triclinic space P-1, a = 9.941(2) Å, b = 14.867(2) Å, c = 22.414(3) Å, α = 80.257(3)°, β = 84.796(2)°, γ = 75.207(3)°, V = 3152.6(8) ų, Z = 4, and d _calc = 1.504 mg/m³; R = 0.0428, R _w = 0.0962 for 8242 reflections with I > 2σ(I). The two CO groups are situated cis to each and are opposite to chlorine and phosphine moieties. The production of the minor propionyl compound 3 is discussed with respect to the trace amount of EtOH that is present in the CHCl₃ solvent that is used in the preparation of [Ru(CO)₃Cl₂]₂.     

Trimethylamine-N-oxide induced disproportionation of Re2(CO)10: Synthesis and X-ray crystal structure of [fac-Re(CO)3(ONMe3)3] [ReO4]

An attempted synthesis of [Re(CO₃) (-OH)]₄,1, by reacting Re₂(CO)₁₀ with an excess of NMe₃O in THF resulted instead in isolation of a disproportionation product, [fac-Re(CO)₃(ONMe₃)₃][ReO₄],2. The structure of2 was determined via X-ray crystallography: tri-clinic,P1^¯,a=9.499(5),b=9.841(2),c=13.448(2)Å,=109.92(2),=106.89(3), =93.15(4)°,D _calc=2.22 g^–3 andZ=2. Least-squares refinement based on 1606 observed (I>3(I)) reflections gave final values ofR=0.040 andR _w=0.047. The cation is a distorted octahedron that exhibits several structural manifestations of steric crowding among the bulky NMe₃O ligands.     

Synthesis, spectroscopy, and X-ray structures of fac-(CO)3(dppe)MnSC(S)H, fac-(CO)3(dppe)ReSC(S)H, fac-(CO)3(dppp)ReSC(S)H, and fac-(CO)3(dppb)ReSC(S)H

The monodentate dithioformato complexes, fac-(CO)₃(dppe)MnSC(S)H (1), fac- (CO)₃(dppe)ReSC(S)H (2), fac-(CO)₃(dppp)ReSC(S)H (3), and fac-(CO)₃ (dppb)ReSC(S)H (4), where dppe is 1,2-bis(diphenylphosphino)ethane, dppp is 1,3-bis(diphenylphosphino)propane, and dppb is 1,4-bis(diphenylphosphino)butane, were synthesized from the treatment of the corresponding hydrides, fac-(CO)₃ (P-P)MSC(S)H with CS₂. Compounds 1–4 crystallize in the monoclinic crystal system: for 1, space group = P2₁/c, a = 15.3139(3) Å, b = 9.7297(4) Å, c = 19.0991(6) Å, = 105.928(1), V = 2736.5 ų, Z = 4; for 2, space group = P2₁/c, a = 15.6395(8) Å, b = 9.8182(5) Å, c = 19.4153(11) Å, = 106.741(1), V = 2854.9(3) ų, Z = 4; for 3, space group = P2₁/n, a = 11.3570(10) Å, b = 19.465(2) Å, c = 15.5702(14) Å, = 104.776(2), V = 3328.3(5) ų, Z = 4; and for 4, space group = C2/c, a = 32.078(2) Å, b = 10.4741(6) Å, c = 19.0608(9) Å, = 94.315(2), V = 6386.1(6) ų, Z = 8.     

Synthesis and crystal structure of 5-amino-4-cyano-1-[(5-methyl-1-t-butyl-4-pyrazolyl)carbonyl]-3-methylthio-1H-pyrazole

The title compound, 5-amino-4-cyano-1-[(5-methyl-1-t-butyl-4-pyrazolyl)carbonyl]-3-methylthio-1H-pyrazole 5, was synthesized by the treatment of 4 (5-methyl-1-t-butylpyrazole-4-carbohydrazide) with 2-cyano-3, 3-dimethylthio-acrylonitrile, and its crystal structure was determined by X-ray diffraction method. The crystal belongs to monoclinic, space group P2₁/c with unit cell parameters a = 13.566(4) Å, b = 10.833(3) Å, c = 11.202(3) Å, α = 90°, β = 98.073(5)°, γ = 90°, V = 1629.9(8) ų, Z = 4, D _c = 1.298, M _r = 318.40, μ = 0.210 mm⁻¹, F(000) = 672, R ₁ = 0.0488 and wR ₂ = 0.1250.     

Reaction of bis(dimethoxyphosphino)dimethylhydrazine (dmpdmh) with PhCCo3(CO)9: synthesis and X-ray characterization of the dmpdmh-bridged polymorphs of PhCCo3(CO)7[(MeO)2PN(Me)N(Me)P(OMe)2]

The tricobalt cluster PhCCo₃(CO)₉ reacts with the bis(phosphanyl)hydrazine ligand bis(dimethoxyphosphino)dimethylhydrazine (dmpdmh) to give the monosubstituted cluster [PhCCo₃(CO)₈]₂(dmpdmh) and the disubstituted cluster PhCCo₃(CO)₇(dmpdmh) as the major products. This latter cluster contains a bridging dmpdmh ligand. Both IR and NMR spectroscopies (³¹P and ¹H) have been employed in the solution characterization of these two clusters. The solid-state structure of PhCCo₃(CO)₇(dmpdmh) was unequivocally established by X-ray diffraction analysis, which has revealed the presence of two different polymorphs for this particular cluster. The first polymorph crystallizes in the monoclinic space group P2₁/n, a = 9.7127(7) Å, b = 17.025(2) Å,c = 16.894(1) Å, = 96.245(5)°, V = 2777.0(4) ų, Z = 4, and d _calc = 1.689 g/cm³; while the second polymorph crystallizes in the orthorhombic space group Pbca, a = 16.925(2) Å, b = 16.208(2) Å, c = 20.541(3) Å, V = 5635(1) ų, Z = 8, and d _calc = 1.665 g/cm³.     

Synthesis, crystal structures, and properties of two manganese(II)-nitroprusside complexes

Two new manganese(II)-1,10-phenanthroline-nitroprusside complexes, [Mn(phen)₃][Fe (CN)₅(NO)]⋯2H₂O⋯0.25CH₃OH (1) and [Mn(phen)₂(H₂O)₂][Fe(CN)₅(NO)]⋯H₂O (2) (where phen is 1,10-phenanthroline) have been synthesized and characterized by X-ray diffraction, electronic paramagnetic resonance (E.P.R.) and IR analyses. Complex 1 crystallizes in the monoclinic space group P2₁/n, with lattice parameters a = 10.0441(15) Å, b = 19.668(2) Å, c = 19.938(3) Å,  β =100.427(14)°, V = 3873.7(10) ų, Z = 4; complex (2) crystallizes in the monoclinic space group C2/c, with a = 17.120(2) Å, b = 13.7925(19) Å, c = 14.4362(17) Å, β = 107.962(12)°, V = 3242.6(7) ų, Z = 4. In the two compounds, three phen ligands 1, or two phen ligands and two cis-related aqua molecules 2, are in a distorted octahedral arrangement around the Mn(II) ion. The nitroprusside anion, [Fe(CN)₅(NO)]²⁻, acts as a counterion. It is intriguing that in complex 2 no cyano bridges are present with two water molecules coordinated to the Mn(II) ion considering that usually the cyano nitrogen atoms are strong donors and could readily replace the coordinating solvent water molecules. Abundant hydrogen bond interactions and π–π stacking between the phen rings in two complexes lead to three-dimensional supramolecular networks.     

Crystal structure analyses of bis(triphenyl- phosphoranyliden)ammonium bis(pentafluoroethyl) argentate, [Ph3P=N=PPh3][Ag(C2F5)2] and bis[bis(triphenylphosphoranyliden)ammonium] tetrachloro-diargentate, [Ph3P=N=PPh3]2[ClAg(μ-Cl)2AgCl]

Bis(triphenylphosphoranyliden)ammonium bis(pentafluoroethyl)argentate, [Ph₃P=N= PPh₃][Ag(C₂F₅)₂] (1) and bis[bis(triphenylphosphoranyliden)ammonium]tetrachloro-diargentate, [Ph₃P=N=PPh₃]₂[ClAg(μ-Cl)₂AgCl] (2) were crystallized from the reaction mixture of pentafluoroethylsilver(I) and bis(triphenylphosphoranyliden)ammonium chlo-ride. Crystallization of 1 occurs in the centrosymmetric monoclinic space group P2₁/c (No. 14) with a = 17.083(2) Å, b = 11.600(2) Å, c = 19.833(2) Å, β = 109.66(1)°, V = 3700.8(7) ų, Z = 4. 2 crystallizes in the centrosymmetric orthorhombic space group Pbca (No. 61) with a = 19.540(1) Å, b = 15.926(1) Å, c = 20.160(1) Å, V = 6273.6(3) ų, Z = 8.     

Crystal structure of cis-[Rh(biq)2Cl2]Cl·3H2O: Solid-state characterization and crystal packing analysis

The title compound, cis-[Rh(biq)₂Cl₂]Cl·3H₂O (biq = 2,2′-biquinoline) crystallized in the monoclinic space group P2 ₁ /n with a = 11.231(2) Å, b = 20.895(4) Å, c = 14.081(3) Å, β = 94.76(3)°, V = 3293.0(11) ų, D _c = 1.565 g cm⁻³, μ = 0.806 mm⁻¹, F(000) = 1576 and Z = 4. It contains a monomeric [Rh(biq)₂Cl₂]⁺ cation, a chloride ion and three molecules of H₂O. The rhodium(III) ion is hexa coordinated forming a distorted octahedral arrangement. The mean Rh(III)–N distance for the four Rh(III)–N bonds is 2.0625 Å. The two chloride atoms are bonded in a cis configuration [Rh(III)–Cl bond distances are 2.329(3) and 2.341(4) Å]. The structure shows a curling stacks of cationic complexes interacting via offset-face-to-face (OFF) π–π aryl interaction motif. Water molecules and chloride ions are hydrogen bonded (H₂O···H–OH and Cl···H–OH) and links the curling stacks by hydrogen bonding via Rh–Cl···H–OH interactions.     

Organometallic derivatives of N-phenylmaleimidetriazoles and quinonetriazoles

The syntheses, properties, and structures of Mn, Cr, Re, and W organometallic derivatives of N-phenyl-1,2,3-triazoles and quinone-1,2,3-triazoles are described. The X-ray structures of eleven compounds are described. 9, a = 11.588(2), b = 11.904(2), 14.179(2) Å, α = 69.407(3)°, β = 70.879(3)°, γ = 78.627(3)°, P-1, R = 0.0739. 10, a = 7.643(1), 9.375(1), 13.077(2) Å, α = 74.292(2)°, β = 74.763(2)°, γ = 71.694(2)°. P-1, R = 0.0415. 11, a = 14.325(4) Å, b = 17.508(5) Å, c = 15.465(5), β = 99.282(5)°, P2/n, R = 0.0610. 17, a = 7.679(2) Å, b = 9.273(2) Å, c = 13.084(3) Å, α = 75.166(3)°, β = 74.651(3)°, γ = 71.613(3)°, P-1, R = 0.0428. 18, a = 5.757(1), 13.470(3), 23.056(4) Å, P2₁2₁2₁, R = 0.0697. 19, a = 8.118(1) Å, b = 10.471(2), 15.027(2) Å, α = 72.848(2)°, β = 82.237(2)°, γ = 71.829(2)°, P-1, R = 0.0597. 23, a = 7.993(1), 9.302(1) Å. C = 13.318(2) Å, α = 94.471(2)°, β = 105.269(2)°, γ = 109.523(2)°, P-1, R = 0.0271. 24, a = 7.583(4), 9.595(5), 13.030(6) Å, α = 76.389(7)°, β = 74.883(7)°, γ = 71.102(7)°, P-1, R = 0.0502. 26, a = 32.757(5) Å, b = 6.7083(9) Å, c = 26.033(4) Å, β = 128.895(5)°, C2/c, R = 0.0489. 31, a = 8.302(2), 8.347(2), 13.794(4) Å, α = 85.749(4)°, β = 81.176(4)°, γ = 74.849(4)°, P-1, R = 0.0400. 32, a = 11.321(2) Å, b = 12.110(2), 18.179(3) Å, β = 103.951(3)°, P2₁/c, R = 0.0318.     

Synthesis, redox properties, and molecular structure of 4,5-diethylthio-4-cyclopenten-1,3-dione: Cyclic voltammetric evidence for a kinetically stable radical anion

The preparation of the new disulfide compound 4,5-diethylthio-4-cyclopenten-l,3-dione (1) from 4,5-dichloro- 4-cyclopenten-l,3-dione and ethanethiol is described. The title compound has been isolated and characterized in solution by IR and NMR spectroscopies, and the solid-state structure solved by X-ray crystallography. 4,5-Diethylthio-4-cyclopenten-l,3-dione crystallizes in the triclinic space group P-l, a = 7.230(4) Å, b = 8.191(5) Å, c = 10.187(6) Å, α = 108.48(1)°, β = 97.75(1)°, γ = 105.90(1)°, V = 533.8(6) ų, Z = 2, and d _calc = 1.346 Mg/m³; R = 0.0406, R _w = 0.0967 for 1394 reflections with I > 2σ(I). The redox properties of 4,5-diethylthio-4-cyclopenten-l,3-dione have been examined by cyclic voltammetry in CH₂C1₂ solution, where a reversible one-electron reduction was found. The reduction behavior of the diethylthio derivative is discussed relative to the closely related 4,5-bis(p-tolylthio)-4-cyclopenten-l,3-dione, whose radical anion exhibits quasi-reversible reduction behavior due to competitive C(dione ring)–S bond cleavage. The differences in the electrochemical behavior of the two disulfides are discussed with respect to the ancillary R group.     

Crystal structure of Co4(CO)10S2 and Co4(CO)10Se2; v(CO) vibrations of a model cluster molecule: Co4(CO)10S2

The crystal structure of Co₄(CO)₁₀S₂ has been redetermined and that of Co₄(CO)₁₀Se₂ obtained by X-ray analysis. The compounds are monoclinic and isomorphous, space groupP2₁/n,Z=2, with (S compound)a=10.42(2)Å,b=6.794(1)Å,c=12.421(2)Å,=97.27(1) and (Se compound)a=10.110(2)Å,b=6.747(2)Å,c=12.592(4)Å,=96.37(2); finalR(S)=0.029,R _w =0.032 for 1414 reflections and finalR (Se)=0.052,R _w =0.054 for 1264 reflections. The molecules, which lie on a crystallographic center of symmetry, consist of a rectangle with Co atoms at the corners, each face of the rectangle being capped by a chalcogen atom. Each Co atom is bonded to two terminal CO groups; there are two bridging CO groups, one on each member of a pair of opposite sides of the rectangle. The vibrational spectra of the sulfur compound are considered in detail. A study of the crystal structure, and recognition of an approximate spectroscopic space group, are shown to be essential for an understanding of thev(CO) infrared spectrum of polycrystalline Co₄(CO)₁₀S₂. In this molecule, intramolecular vibrational coupling in the crystal leads to extensive modifications of the infrared-activev(CO) molecular coordinates.     

The crystal structure of tris(4-methylpyridine) tricarbonylmolybdenum(0)

The title compound, Mo(4-CH₃C₅H₄N)₃(CO)₃, is monoclinic, P2₁/c, with cell dimensionsa=10.385(1),b=13.572(2),c=15.522(2) Å, =105.08(1)°,Z=4. The complex isfac-octahedral with approximate three-fold symmetry. The Mo–C bond lengths are 1.901–1.904(7) Å, distinctly shorter than in the parent Mo(CO)₆, and the Mo–N bond lengths are 2.297–2.331(5) Å.     

Structural characterization of the edge double-bridged triruthenium cluster complex Ru3(μ-Cl)2(CO)8(PPh3)2

The title compound is Ru₃(-Cl)₂(CO)₈(PPh₃)2. Crystal data: formula C₄₄H₃₀O₈Cl2P2Ru₃;f _w =1122.9; monoclinic,P2₁; cell parameters (at 293 K)a=10.971(2) Å,b=17.066(2) Å,c=11.833(2) Å,=92.91(1)°,V=2213 ų,Z=2, _calcd=1.68, _meas=1.68. Final discrepancy indices areR(F)=0.030,R _W (F)=0.036. The structure consists of an open trinuclear unit involving two metal-metal bonds [Ru(1)-Ru(2)=2.845(1) Å, Ru(2)-Ru(3)=2.860(1) Å]. The open edge of the metal framework [Ru(1)Ru(3)=3.254(1) Å] is supported by two symmetric bridging chloride ligands [Cl(1)-Ru(1)=2.461(2) Å; Cl(1)-Ru(3)=2.464(2) Å; Cl(2)-Ru(1)=2.470(2) Å; Cl(2)-Ru(3)=2.472(2) Å]. Both phosphorus ligands are cis to the Cl atoms and trans to the unique ruthenium atom Ru(2). Geometric features of the edge dibridged complex are discussed.     

Synthesis and structural characterization of fac-BrMn(CO)3{PH(C6H5)2}2

In attempts to find appropriated methods for preparation of unstable sulfinyl and sulfonylphosphane complexes we have synthesized the diphenylphosphine complexes of Mn(I), BrMn(CO)₄PHPh₂, (1) and BrMn(CO)₃(PHPh₂)₂ (2). Both should undergo electrophilic substitution in the presence of an adequated base. Parallel to the reactions of stabilization of phosphanes we have studied by means of x-ray analysis the structure of fac-BrMn(CO)₃(PHPh₂)₂ (2). The compound crystallizes in the triclinic space group P, a = 9.840(2), b = 11.207(2), c = 13.083(3) Å, = 72.00(3), = 69.59(3), = 81.41(3)°, U = 1284.7(4) ų, and Z = 2. In this complex the manganese atom shows an octahedral coordination geometry, with three carbonyl ligands in a fac arrangement, and one bromide and two diphenylphosphine ligands cis to each other.     

CO substitution in Ru3(CO)12 by 2,3-bis(diphenylphosphino)-N-phenyl-maleimide (bppm). X-ray diffraction structure of Ru2(CO)6(bppm)

The cluster Ru₃(CO)₁₂ reacts with the diphosphine ligand 2,3-bis(diphenylphosphino)-N-phenyl-maleimide (bppm) in toluene solution at 100C by fragmentation to give a 2:1 mixture of the donor–acceptor complex Ru₂(CO)₆(-bppm) and the phosphido-bridged species Ru₂(CO)₆ , respectively. The new diruthenium compounds have been isolated by chromatography and characterized in solution by IR and NMR (¹H and ³¹P) spectroscopies, in addition to X-ray diffraction analysis in the case of Ru₂(CO)₆( ₂ -bppm). Ru₂(CO)₆( ₂ -bppm), which exists as two crystallographically independent molecules in the unit cell, crystallizes in the orthorhombic space group Pbca, a = 18.8441(9), b = 21.352(2), c = 36.510(2) Å, V = 14,690(1) ų, z = 16, D _calc = 1.649 g/cm³; R = 0.0356, and R _w = 0.0812 for 17732 observed reflections. The reactivity of the bis(diphenylphosphino)-N-phenyl-maleimide ligand with Ru₃(CO)₁₂ under thermolysis conditions is contrasted with the related diphosphine ligands 2,3-bis(diphenylphosphino)maleic anhydride (bma) and 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd).     

Synthesis and characterization of Bis(μ-sulfido)bis[{O,O-dimethyldithiophosphato}oxomolybdenum(V)]. Crystal structure of Mo2O2(Φ-S2)[S2P(OMe)2]2.C6H6

Bis(μ-sulfido)bis[{O,O-dimethyldithiophosphato}oxomolybdenum(V) was prepared by dropwise addition of an ethanolic solution of the ammonium salt of O,O-dimethyldithio-phosphoric acid to a hot aqueous solution of MoCl₅. The X-ray structure of Mo₂O₂(Φ-S₂)[S₂P(OMe)₂]₂.C₆H₆ was determined. Crystal data: Monoclinic, P2₁/n, a = 6.9788(6), b = 22.616(3), c = 14.633(1) Å, β = 101.193(9)°, V = 2265.5(4) Å⁻³, Z = 4. The immediate environment around the two molybdenum atoms is essentially square pyramidal if the Mo—Mo interaction is ignored. The terminal oxygen atoms are in the syn conformation.     

The structures of three trimethylarsine-boron trihalide adducts: (CH3)3AsBCl3, (CH3)3AsBBr3, and (CH3)3AsBI3

An X-ray structure analysis of three trimethylarsine-boron trihalide adducts has been undertaken. Crystals of (CH₃)₃AsBCl₃ and (CH₃)₃AsBBr₃ are monoclinic with space groupP2₁/m (No. 11) withZ=2 while those of (CH₃)₃AsBI₃ are orthorhombic with space groupPnma (No. 62) withZ=4. For (CH₃)₃AsBCl₃,a=6.497(3) Å,b=10.735(3) Å,c=7.070(2) Å,=111.8(3)°,V=458.4(3) ų,R=0.0343. For (CH₃)₃AsBBr₃,a=6.672(4) Å,b=11.135(7) Å,c=7.199(4) Å,=111.5(1)°,V=497.7(5) ų,R=0.0434. For (CH₃)₃ÅsBI₃,a=13.113(7) Å,b=11.733(5) Å,c=7.387(3) Å,V=1136.5(5) ų,R=0.0329. The As-B bond lengths are 2.065(6), 2.04(1), and 2.03(1) Å, respectively, for the chloride, bromide, and iodide. These and other structural parameters are discussed with reference to previous predictions based on vibrational spectra and previous structural studies on the trimethyl-phosphine and trimethylamine adducts.