The ReH6[P(C6H5)3]2 ion as a ligand: complexes with M(CO)3 fragments (M = Cr, Mo, W)

The reactions of [(H₅C₆)₃P]₂ReH₆⁻ with (CH₃CN)₃Cr(CO)₃, (diglyme)Mo(CO)₃ or (C₃H₇CN)₃W(CO)₃ led to the formation of [(H₅C₆)₃P]₂ReH₆M(CO)₃⁻ (M = Cr, Mo, W) complexes. These have been characterized by IR and NMR spectroscopies, as well as elemental analyses. A single crystal X-ray diffraction study has also been carried out for the M = Cr complex as a K(18-crown-6)⁺ salt. The complex crystallizes as a THF monosolvate in the monoclinic space group P2₁/n with a = 22.323(6), B = 9.523(2), C = 27.502(5) Å, β = 104.98(2)⁰ and V = 5648 ų for Z = 4. The Re---Cr separation is 2.5745(12) Å, and the two phosphine ligands are oriented unsymmetrically. Although the hydride ligands were not found, the presence of three bridging hydrides and a dodecahedral coordination geometry about rhenium could be inferred. Low temperature ¹H and ³¹P NMR spectroscopic studies did not reveal the low symmetry of the solid state structure.     

First- and second-order mechanisms for oxidative addition for bound methyl disulfide in the complex W(CO)3(phen)(MeSSMe)

The rate of oxidative addition of methyl disulfide in the complex W(CO)₃(1,10-phenanthroline) (MeSSMe) in methylene chloride has been studied. The dominant reaction pathway is second order in metal complex and inhibited by excess methyl disulfide. Formation of a dinuclear complex [W(CO)₃(phen)]₂(MeSSMe) is proposed to lead to the transition state for cleavage of the sulfur-sulfur bond in the second-order mechanism. In neat methyl disulfide, or in concentratred solutions of methyl disulfide at low metal complex concentrations, the reaction occurs at reduced rate and follows a first-order mechanism. Addition of Mo(CO)₃(1,10-phenanthroline) (MeSSMe) to the corresponding tungsten complex results in a ten-fold increase in the rate of oxidative addition of the tungsten complex and production of Mo(CO)₄(1,10-phenanthroline) as the sole molybdenum-containing product. The faster rate of reaction in the presence of the molybdenum complex is attributed to the faster formation of the heteronuclear dinuclear intermediate by initial loss of MeSSMe from the molybdenum versus tungsten center. Additional kinetic/mechanistic studies are described using a new flow-through FT-IR/microscope reaction system designed to allow convenient monitoring of small quantities of sensitive/hazardous reactants.     

Spectroscopic and electrical properties of the [W(C3Se5)3] anion complex (C3Se5 = 1,3-diselenole-2-selone-4,5-diselenolate) and the oxidized species

[NBuⁿ₄]₂[W(C₃Se₅)₃] (C₃Se₅²⁻ = 1,3-diselenole-2-selone-4,5- diselenolate(2−)) was prepared by the reaction of Na₂[C₃Se₅] with WCl₆ in ethanol, followed by addition of [NBuⁿ₄]Br. The cyclic voltammogram in dichloromethane exhibits two oxidation peaks at −0.04 and +0.03 V (versus SCE). The complex reacted with [Fe(C₅Me₅)₂][BF₄], iodine or [TTF]₃[BF₄]₂ (TTF^·+ = the tetrathiafulvalenium radical cation) in acetonitrile to afford the oxidized complexes [Fe(C₅Me₅)₂]_0.5[W(C₃Se₅)₃], [NBuⁿ₄]_0.1[W(C₃Se₅)₃] and [TTF]_0.5[W(C₃Se₅)₃], respectively. Current-controlled electrochemical oxidation of the complex in acetonitrile gave [NBuⁿ₄]_0.6[W(C₃Se₅)₃]. The oxidized complexes exhibit electrical conductivities of 4.7×10 ⁻⁵−1.5×10⁻³ S cm⁻¹ at room temperature measured for compacted pellets. Electronic absorption, IR and ESR spectra of these complexes are discussed.     

Syntheses and characterization of the W(II) and W(III) N2 complexes, [WCl2(PMe3)3]2N2 and [WCl3(PMe3)2]2N2

Refluxing WCl₄(PMe₃)₃ under a nitrogen atmosphere in the presence of two equivalents of sodium amalgam leads to a reduction to the W(II) complex [cis,mer-WCl₂(PMe₃)₃]₂N₂ (1), which can be converted to [mer,trans-WCl₃(PMe₃)₂]₂N₂ (2) via appropriate oxidation/chlorination. Structural data have been obtained for both complexes, and demonstrate significantly increased steric crowding in 1 due to PMe₃/PMe₃ interactions. The N-N bond distances in the two compounds are similar, at 1.279(4) and 1.243(18) Å, respectively.     

Reactions of the haloalcohols HO(CH2)nCl (n = 2, 3) with platinum(II) - alkynyl and -alkyne complexes. X-ray crystal structure of trans-[Pt(Me) {C(OCH2CH2Cl) (CH2Ph)} (PPh3)2] [BF4]

The chloro complexes trans-[Pt(Me)(Cl)(PPh₃)₂], after treatment with AgBF₄, react with 1-alkynes HC---C---R in the presence of NEt₃ to afford the corresponding acetylide derivatives trans-[Pt(Me) (C---C---R) (PPh₃)₂] (R = p-tolyl (1), Ph (2), C(CH₃)₃ (3)). These complexes, with the exception of the t-butylacetylide complex, react with the chloroalcohols HO(CH₂)_nCl (n = 2, 3) in the presence of 1 equiv. of HBF₄ to afford the alkyl(chloroalkoxy)carbene complexes trans-[Pt(Me) {C[O(CH₂)_nCl](CH₂R) } (PPh₃)₂][BF₄] (R = p-tolyl, N = 2 (4), N = 3 (5); R=Ph, N = 2 (6)). A similar reaction of the bis(acetylide) complex trans-[Pt(C---C---Ph)₂(PMe₂Ph)₂] with 2 equiv. HBF₄ and 3-chloro-1-propanol affords trans-[Pt(C---CPh) {C(OCH₂CH₂CH₂Cl)(CH₂Ph) } (PMe₂Ph)₂][BF₄] (7). T alkyl(chloroalkoxy)-carbene complex trans-[Pt(Me) {C(OCH₂CH₂Cl)(CH₂Ph) } (PPh₃)₂][BF₄] (8) is formed by reaction of trans-[Pt(Me)(Cl)(PPh₃)₂], after treatment with AgBF₄ in HOCH₂CH₂Cl, with phenylacetylene in the presence of 1 equiv. of n-BuLi. The reaction of the dimer [Pt(Cl)(μ-Cl)(PMe₂Ph)]₂ with p-tolylacetylene and 3-chloro-1-propanol yields cis-[PtCl₂{C(OCH₂CH₂CH₂Cl)(CH₂C₆H₄-p-Me}(PMe₂Ph)] (9). The X-ray molecular structure of (8) has been determined. It crystallizes in the orthorhombic system, space group Pna2₁, with a = 11.785(2), B = 29.418(4), C = 15.409(3) Å, V = 4889(1) ų and Z = 4. The carbene ligand is perpendicular to the Pt(II) coordination plane; the PtC(carbene) bond distance is 2.01(1) Å and the short C(carbene)-O bond distance of 1.30(1) Å suggests extensive electronic delocalization within the Pt---C(carbene)---O moietry.     

Correlation of structure and emission in solid state copper(I) complexes; [Cu4I4(CH3CN)2(L)2], L = aniline derivative

Four complexes of the type [Cu₄I₄(CH₃CN)₂(L)₂], L = aniline derivative: Cu₄I₄(CH₃CN)₂(2,6-dimethylaniline)₂ (I), triclinic, , a = 12.449(3), B = 14.108(6), C = 10.606(4) Å, = 73.46(3), β = 95.00(2), γ = 73.42(3)°, V = 1682.3(10) ų; Cu₄I₄(CH₃CN)₂(o-ethylaniline)₂ (II), triclinic,

Full-size image

, V = 1734.0(8) ų; Cu₄I₄(CH₃CN)₂(6-ethyl-o-toluidine)₂ (III), orthorhombic, Pnam, a = 14.976(6), b = 21.187(6), C = 12.545(2) Å, V = 3980.7(2) ų; Cu₄I₄(CH₃CN)₂(p-anisidine)₂ (IV), monoclinic, A2/a, A = 20.032(10), B = 7.863(1), C = 18.715(9) Å, β = 101.56(4)°, V = 2888.0(2) ų; were examined by single crystal X-ray diffraction. Complexes I and II have no internal symmetry elements, III has an internal mirror and IV has a two-fold axis. Ab initio calculations based on the atomic positional parameters of complexes containing the three types of symmetry elements reveal HOMO orbitals to be dominated by the p orbitals of the iodine atoms whereas the LUMO orbitals contain major contributions from copper based p orbitals.     

Solvent influence in the formation of normal and abnormal carbene complexes in reactions of imidazolium salts with [Ir(H)2(PPh3)2(OCMe2)2]BF4

Abnormal and normal carbene complexes are formed in reactions of 2-pyridylmethylimidazolium salts with [Ir(H)₂(PPh₃)₂(OCMe₂)₂]BF₄ at room temperature in tetrahydrofuran (THF) or dichloromethane (CH₂Cl₂). Reactions in THF lead to the formation of abnormal carbene (C-5 bound), while reactions in CH₂Cl₂ lead to formation of normal carbene (C-2 bound).     

Selective synthesis of triangular cluster oxido-sulfidocomplexes of Mo and W: High yield preparations of [Mo3O2S2(H2O)9], [W3O2S2(H2O)9], [W2MoO2S2(H2O)9] and their derivatization

Reaction of [Mo₂O₂(μ-S)₂(H₂O)₆]²⁺ with Mo(CO)₆ or metallic Mo under hydrothermal conditions (140 °C, 4 M HCl) gives oxido-sulfido cluster aqua complex [Mo₃(μ₃-S)(μ-O)₂(μ-S)(H₂O)₉]⁴⁺ (1). Similarly, [W₃(μ₃-S)(μ-O)₂(μ-S)(H₂O)₉]⁴⁺ (2) is obtained from [W₂O₂(μ-S)₂(H₂O)₆]²⁺ and W(CO)₆. While reaction of [Mo₂O₂(μ-S)₂(H₂O)₆]²⁺ with W(CO)₆ mainly proceeds as simple reduction to give 1, [W₂O₂(μ-S)₂(H₂O)₆]²⁺ with Mo(CO)₆ produces new mixed-metal cluster [W₂Mo(μ₃-S)(μ-O)₂(μ-S)(H₂O)₉]⁴⁺ (3) as main product. From solutions of 1 in HCl supramolecular adduct with cucurbit[6]uril (CB[6]) {[Mo₃O₂S₂(H₂O)₆Cl₃]₂CB[6]}Cl₂⋅18H₂O (4) was isolated and structurally characterized. The aqua complexes were converted into acetylacetonates [M₃O₂S₂(acac)₃(py)₃]PF₆ (M₃ = Mo₃, W₃, W₂Mo; 5a-c), which were characterized by X-ray single crystal analysis, electrospray ionization mass spectrometry and ¹H NMR spectroscopy. Crystal structure of (H₅O₂)(Me₄N)₄[W₃(μ₃-S)(μ₂-S)(μ₂-O)₂(NCS)₉] (6), obtained from 2, is also reported.     

The coordination chemistry of cationic main group clusters: syntheses and structures of [Fe3(Se2)2(CO)10] and [Fe4(Se2)3(CO)12]

The reactions of the polysulfur and selenium cationic clusters S₈²⁺ and Se₈²⁺ with various iron carbonyls were investigated. Several new chalcogen containing iron carbonyl cluster cations were isolated, depending on the nature of the counteranion. In the presence of SbF₆⁻ as a counterion, the cluster [Fe₃(E₂)₂(CO)₁₀] [SbF₆]₂·SO₂ (E = S, Se) could be isolated from the reaction of E₈²⁺ and excess iron carbonyl. The cluster is a picnic-basket shaped molecule of two iron centers linked by two Se₂ groups, with the whole fragment capped by an Fe(CO)₄ group. Crystallographic data for C₁₀O₁₂Fe₃Se₄Sb₂F₁₂S (I): space group monoclinic P2₁/c, A = 11.810(9), b = 24.023(6), c = 10.853(7) Å, β = 107.15(5)°, V = 2942(3) ų, Z = 4, R = 0.0426, R_w = 0.0503. When Sb₂F₁₁⁻ is present as the counterion, or Se₄[Sb₂F₁₁]₂ is used as the cluster cation source, a different cluster can be isolated, which has the formula [Fe₄(Se₂)₃(CO)₁₂] [SbF₆]₂·3SO₂. The dication contains two Fe₂Se₂ fragments bridged by an Se₂ group. Crystallographic data for C₁₂O₁₈Fe₄Se₆Sb₂F₁₂S₃ (III): space group triclinic , b = 18.400(9), C = 10.253(4) Å, = 93.10(4), β = 103.74(3), γ = 93.98(3)°, V = 1995(1) ų, Z = 2, R = 0.0328, R_w = 0.0325. The CO stretches in the IR spectrum all show a large shift to higher wavenumbers, suggesting almost no τ backbonding from the metals. This also correlates with the observed bond distances. All the compounds are extremely sensitive to air and water, and readily lose SO₂ when removed from the solvent. Thus all the crystals were handled at −100°C. The clusters seem to be either insoluble or unstable in all solvents investigated.     

Synthesis and characterization of SrCu2(O2CR)3(bdmap)3 and Bi2(O2CCH3)4(bdmap)2(H2O) (R = CH3, CF3; bdmap = 1,3-bis(dimethylamino)-2-propanolato)

New mixed metal complexes SrCu₂(O₂CR)₃(bdmap)₃ (R = CF₃ (1a), CH₃ (1b)) and a new dinuclear bismuth complex Bi₂(O₂CCH₃)₄(bdmap)₂(H₂O) (2) have been synthesized. Their crystal structures have been determined by single-crystal X-ray diffraction analyses. Thermal decomposition behaviors of these complexes have been examined by TGA and X-ray powder diffraction analyses. While compound 1a decomposes to SrF₂ and CuO at about 380°C, compound 1b decomposes to the corresponding oxides above 800°C. Compound 2 decomposes cleanly to Bi₂O₃ at 330°C. The magnetism of 1a was examined by the measurement of susceptibility from 5–300 K. Theoretical fitting for the susceptibility data revealed that 1a is an antiferromagnetically coupled system with g = 2.012(7), −2J = 34.0(8) cm⁻¹. Crystal data for 1a: C₂₇H₅₁N₆O₉F₉Cu₂Sr/THF, monoclinic space group P2₁/m, A = 10.708(6), B = 15.20(1), C = 15.404(7) Å, β = 107.94(4)°, V = 2386(2) ų, Z = 2; for 1b: C₂₇H₆₀N₆O₉Cu₂Sr/THF, orthorhombic space group Pbcn, A = 19.164(9), B = 26.829(8), C = 17.240(9) Å, V = 8864(5) ų, Z = 8; for 2: C₂₂H₄₈O₁₁N₄Bi₂, monoclinic space group P2₁/c, A = 17.614(9), B = 10.741(3), C = 18.910(7) Å, β = 109.99(3)°, V = 3362(2) ų, Z = 4.     

The new enneanuclear nickel carbonyl anion [Ni9(CO)16] and its relationships with the [Ni12(CO)21] and [Ni6Rh3(CO)17] clusters

The reaction of [N(PPh₃)₂]₂[Ni₆(CO)₁₂] with Cu(PPh₃)_xCl (x=1, 2), as well as the degradation of [N(PPh₃)₂]₂[H₂Ni₁₂(CO)₂₁] with PPh₃, affords the new and unstable dark orange–brown [N(PPh₃)₂]₂[Ni₉(CO)₁₆].THF salt in low yields. This salt has been characterized by a CCD X-ray diffraction determination, along with IR spectroscopy and elemental analysis. The close-packed two-layer metal core geometry of the [Ni₉(CO)₁₆]²⁻ dianion is directly related to that of the bimetallic [Ni₆Rh₃(CO)₁₇]³⁻ trianion and may be envisioned to be formally derived from the hcp three-layer geometry of [Ni₁₂(CO)₂₁]⁴⁻ by the substitution of one of the two outer [Ni₃(CO)₃(μ−CO)₃]²⁻ layers with a face-bridging carbonyl group.     

Ru2(CO)4(OOCR)2L2 sawhorse-type complexes containing axial 5-(4-pyridyl)-10,15,20-triphenylporphyrin ligands

The thermal reaction of Ru₃(CO)₁₂ with various carboxylic acids (benzoic, 4-hydroxyphenylacetic, ferrocenic, stearic, oleic, 4-(octadecyloxy)benzoic) in refluxing tetrahydrofuran, followed by addition of 5-(4-pyridyl)-10,15,20-triphenylporphyrin (L), gives the dinuclear complexes Ru₂(CO)₄(OOCR)₂L₂ (1: R = -C₆H₅, 2: R = -CH₂-p-C₆H₄OH, 3: R = -C₅H₄FeC₅H₅, 4: R = -(CH₂)₁₆CH₃, 5: R = -(CH₂)₇CHCH(CH₂)₇CH₃, 6: R = -p-C₆H₄O(CH₂)₁₇CH₃). Complexes 1-6 were characterised by IR, NMR, and ESI-MS as well as by elemental analysis. The UV-Vis spectra show the Soret band centred at 417 nm and the Q bands at 515, 550, 590 and 645 nm, respectively.     

Synthesis, structure and properties of TTF-carboxylate bridged paddlewheel dirhodium complexes, Rh2(BuCO2)3(TTFCO2) and Rh2(BuCO2)2(TTFCO2)2

Reaction of tetrathiafulvalene carboxylic acid (TTFCO₂H) with paddlewheel dirhodium complex Rh₂(Bu^tCO₂)₄ yielded TTFCO₂-bridged complexes Rh₂(Bu^tCO₂)₃(TTFCO₂) (1) and cis- and trans-Rh₂(Bu^tCO₂)₂(TTFCO₂)₂ (cis- and trans-2). Their triethylamine adducts [1(NEt₃)₂] and cis-[2(NEt₃)₂] were purified and isolated with chromatographic separation, and characterized with single crystal X-ray analysis. Trans-[2(NEt₃)₂] is not completely separated from a mixture of cis- and trans-[2(NEt₃)₂], but its single crystals were obtained from a solution of the mixture. A three-step quasi-reversible oxidation process was observed for 1 in MeCN. The first two steps correspond to the oxidation of the TTFCO₂ moiety and the last one is the oxidation of the Rh₂ core. The oxidation of cis-2 is observed as a two-step process with very similar E_1/2 values to those of the first two processes for 1. Both 1⁺ and cis-2²⁺ in MeCN at room temperature show isotropic ESR spectra with a g value of 2.008 and a_H = 0.135 mT for two equivalent H atoms and a_H = 0.068 mT for one H atom. The redox and ESR data of cis-2 suggest that the intramolecular interaction between the TTF moieties is very small.     

Comparison in halide binding ability between the unsaturated clusters [Pd3(μ-dppm)3(CO)] and [PdPtCo(μ-dppm)2(CO)3(CNBu)] (dppm = Ph2PCH2PPh2)

The trinuclear clusters [Pd₃(μ-dppm)₃(CO)]²⁺ and [PtPdCo(μ-dppm)₂(CO)₃(CN^tBu)]⁺ exhibit a large and a small cavity, respectively, formed by the phenyl rings of the bridging diphosphine ligands. Their binding constants (K₁₁) with halide ions (X⁻) were obtained by UV-Vis spectroscopy. The binding ability varies as I⁻ > Br⁻ > Cl⁻, and [Pd₃(μ-dppm)₃(CO)]²⁺ > [ptPdCo(μ-dppm)₂-(CO)₃(CN^tBu)]⁺. The MO diagram for the related cluster [Pd₂Co(μ-dppm)₂(CO)₄]⁺ has been addressed theoretically in order to predict the nature of the lowest energy electronic bands. For this class of compounds, the lowest energy bands are assigned to charge transfers from the Co center to the Pd₂ centers.     

Main group derivatives of a cyclometallated iron carbonyl anion. Crystal structures of Fe(CO)2{P(OPh)3}{(PhO)2POC6H4}(SnPh3) and two isomers of Fe(CO)2{P(OPh)3}{(PhO)2POC6H4}(I)

The iron hydrido complex HFe(CO)₂{P(OPh)₃}{(PhO)₂POC₆H₄} (1), was rapidly deprotonated by DBU or [BzMe₃N][OH] in THF to afford the new carbonyl iron anion [Fe(CO)₂{P(OPh)₃}{(PhO)₂POC₆H₄}]⁻ ([2]⁻), containing an ortho-metallated triphenyl phosphite ligand. Complex [2]⁻ reacted with triorganostannyl and plumbyl salts and with halogens to give the octahedral Fe^II compounds Fe(CO)₂{P(OPh)₃}{(PhO)₂POC₆H₄}(X) (X=SnPh₃, 3; SnMe₃, 4; PbPh₃, 5; PbMe₃, 6; Cl, 7; Br, 8; I, 9). The Group 14 complexes 3-6 were obtained in one isomeric form in which the P^III-donor atoms are mutually cis, the carbonyl ligands are cis and the P(OPh)₃ and MR₃ (M=Sn, Pb; R=Ph, Me) groups are trans as determined by solution-state IR, ³¹P and ¹³C NMR spectroscopic data. This geometry was confirmed for 3 by a single crystal X-ray diffraction study. The halide complexes, however, were obtained as a mixture of isomers. The major isomer (7, X=Cl; 8a, X=Br; 9a, X=I) has cis P atoms, trans CO groups and the halide located trans to the phosphorus atom of the ortho-metallated phosphite ligand. The structure of 9a was confirmed by an X-ray diffraction study. Two other isomers, designated 8b (X=Br) and 9b (X=I), with cis P atoms and cis CO groups were isolated from the reactions of [2]⁻ with Br₂ and I₂, respectively. The structure of the latter was established by X-ray crystallography and is related to 9a by exchange of the P(OPh)₃ ligand and a carbonyl group such that the metal-bound C atom of the five-membered metallacycle is trans to CO. The stereo-geometry of 8b could not be unambiguously assigned from the spectroscopic data; however, two of the seven possible geometric isomers were suggested as plausible structures.     

Five-coordinate rhenium(III)-thiolato complexes: the structure of [Re(SCH2PhOCH3)3(PPh3)2]

A novel five-coordinate rhenium(III)-thiolato complex, Re(SCH₂C₆H₄OCH₃-p)₃(PPh₃)₂ has been isolated during the reaction of trans-ReOCl₃(PPh₃)₂ with p-methoxybenzyl mercaptan. In the unexpected structure that was acquired, the central metal has undergone a reduction from Re(V) to Re(III). The five-coordinate Re(III) complex has been characterized by spectroscopic methods, elemental analysis and X-ray crystallography. X-ray crystallographic studies showed the coordination geometry around rhenium to be that of a trigonal bipyramid. The basal plane is defined by three sulfur atoms of the monodentate ligand, while the two apical positions are occupied by two phosphines of the precursor.     

Kinetic studies on the reactions of HCl with trans-[MoL(CNPh)(Ph2PCH2CH2PPh2)2] (L=N2, H2 or CO)

The kinetics of the reactions between anhydrous HCl and trans-[MoL(CNPh)(Ph₂PCH₂CH₂PPh₂)₂] (L=CO, N₂ or H₂) have been studied in thf at 25.0 °C. When L=CO, the product is [MoH(CO)(CNPh)(Ph₂PCH₂CH₂PPh₂)₂]⁺, and when L=H₂ or N₂ the product is trans-[MoCl(CNHPh)(Ph₂PCH₂CH₂PPh₂)₂]. Using stopped-flow spectrophotometry reveals that the protonation chemistry of trans-[MoL(CNPh)(Ph₂PCH₂CH₂PPh₂)₂] is complicated. It is proposed that in all cases protonation occurs initially at the nitrogen atom of the isonitrile ligand to form trans-[MoL(CNHPh)(Ph₂PCH₂CH₂PPh₂)₂]⁺. Only when L=N₂ is this single protonation sufficient to labilise L to dissociation, and subsequent binding of Cl⁻ gives trans-[MoCl(CNHPh)(Ph₂PCH₂CH₂PPh₂)₂]. At high concentrations of HCl a second protonation occurs which inhibits the substitution. It is proposed that this second proton binds to the dinitrogen ligand. When L=CO or H₂, a second protonation is also observed but in these cases the second protonation is proposed to occur at the carbon atom of the aminocarbyne ligand, generating trans-[MoL(CHNHPh)(Ph₂PCH₂CH₂PPh₂)₂]²⁺. Addition of the second proton labilises the trans-H₂ to dissociation, and subsequent rapid binding of Cl⁻ and dissociation of a proton yields the product trans-[MoCl(CNHPh)(Ph₂PCH₂CH₂PPh₂)₂]. Dissociation of L=CO does not occur from trans-[Mo(CO)(CHNHPh)(Ph₂PCH₂CH₂PPh₂)₂]²⁺, but rather migration of the proton from carbon to molybdenum, and dissociation of the other proton produces [MoH(CO)(CNPh)(Ph₂PCH₂CH₂PPh₂)₂]⁺.     

Ligand connected metal clusters. The molecular structures and solid state packing of {Ru3(CO)11}2(bis(diphenylphosphino)ethane) and {Ru3(CO)11}2(1,4-bis(diphenylphosphino)benzene)

The preparation and structural characterization of {Ru₃(CO)₁₁}₂(1,4-bis(diphenylphosphino)benzene), a modified synthesis of 1,4-bis(diphenylphosphino)benzene, and the structural characterization of {Ru₃(CO)₁₁}₂(bis(diphenylphosphino)ethane) are reported. In both compounds two metal cluster units are connected through ditertiary-phosphine ligands. Both molecules consist of centrosymmetric units in which the diphosphine ligands are largely covered by the triangular ruthenium clusters. No direct interaction between the two cluster units occurs within individual molecules. Molecular packing in the solid state is dominated by interactions between sets of carbon monoxide ligands in motifs that were previously identified in the solid state structure of the parent cluster, Ru₃(CO)₁₂.     

Dynamic properties of the fluxional Rh2H(μ-PPh2)2(PPh3)3 complex

The rhodium dimer [Rh₂H(PPh₂)₂(PPh₃)₃]⁻ was prepared from RhCl(PPh₃)₃ and K₄Sn₉ in the presence of 2,2,2-cryptand in ethylenediamine/toluene solvent mixtures. The [K(2,2,2-crypt)]⁺ salt was isolated and characterized via NMR and X-ray diffraction studies. The solid state structure reveals a binuclear, diphenylphosphido-bridged, 32 electron Rh(I)-Rh(I) complex with edge-shared tetrahedral and square planar Rh centers with overall C_s point symmetry. 1-D and 2-D ¹H, ³¹P, and ³¹P{¹H} NMR experiments were used to characterize the complex.     

A new mixed-valence hexanuclear cobalt complex, [Co4Co2(dea)2(Hdea)4)(piv)4](ClO4)2·H2O: Synthesis, crystal structure and magnetic properties

A new Co^II/Co^III hexanuclear complex, [Co₄^IICo₂^III(dea)₂(Hdea)₄)(piv)₄](ClO₄)₂·H₂O 1, has been obtained by reacting cobalt(II) perchlorate, diethanolamine, and pivalic acid (H₂dea = diethanolamine and piv = pivalato anion). The cobalt ions are held together by four μ₃ and four μ₂ alkoxo bridges as well as by four syn-syn carboxylato groups. The hexanuclear motif contains four Co(II) and two Co(III) ions. The {Co^II₄Co^III₂(μ₂-O)₄(μ₃-O)₄} core can be described as a four face-sharing monovacant and bivacant distorted heterocubane units. The cobalt(III) ions are hexacoordinated. Two of the cobalt(II) are hexacoordinated, while the two others are pentacoordinated with a bipyramidal stereochemistry. The magnetic properties of 1 have been investigated in the temperature range 1.9-300 K. Compound 1 exhibits an overall antiferromagnetic behaviour with a ground singlet spin state.