Synthesis and characterization of the new mixed-metal,mixed-chalcogen clusters Fe2 M(CO)10(μ3-S)(μ3-Te) (M=W,Mo). crystal structure of Fe2W(CO)10(μ3-S)(μ3-Te)

The new clusters Fe₂ M(CO)₁₀(µ₃-S)(µ₃-Te), I (M=W) and 2 (M=Mo) have been isolated from the room temperature reaction of Fe₂(CO)₆(µ-STe) andM(CO)₅(THF) (M=W, Mo), respectively. Compounds1 and2 have been characterized by IR, 125 Te NMR spectroscopy, and elemental analysis. The structure of compound1 has been established by X-ray crystallography. It belongs to the triclinic space groupP witha=6.844(2) Å,b=9.397(2) Å,c=13.681(10) Å, =81.64(2)°,=81360r,=812(2)°,V=861.2(3) ų,Z=2,D _e =2.835 g cm^–3. Full-matrix least-squares refinement of1 converged to R=0.043, andR _w .=0.115. The structure consists of a Fe₂ WSTe square pyramid and the W atom occupies the apical site of the square pyramid.     

Cluster chemistry: L. Trapping of arylnitrenes formed by cleavage of azoarenes in reactions with M3(CO)12 (M = Fe or Ru): X-ray structure of Ru3(μ3-NPh)2(μ-dppm)(CO)7

Trinuclear products obtained from reactions between M₃(CO)₁₂ (M = Fe or Ru) and azobenzenes are shown to have the structure M₃(μ₃-NAr)₂(CO)₉, rather than the o-semidine formulation proposed earlier. ETC CO-substitution reactions are similar to those of Ru₃(CO)₁₂, with isocyanides occupying axial sites and tertiary phosphines and phosphites occupying equatorial sites on the Ru₃(μ₃-NPh)₂(μ-dppm)(CO)₇, in which the dppm ligand spans the non-bonded Ru … Ru vector.     

Synthesis,molecular structure and spectroscopic characterization of MO(CO)2I2 (η2-dppm)(η1-dppm)

A new, high-yield method has been developed for the preparation of MO(CO)₂I₂(η²-dppm)(η¹-dppm). The title compound was prepared by the reaction of [Et₄N][Mo(CO)₄I₃] with dppm in benzene in 95% yield. It has been characterized by a single-crystal X-ray study. The crystallographic data are as follows: monoclinic, space group P2₁/n, a = 19.023(4) Å, b = 14.439(3) Å, c = 20.141(5) Å, β = 100.45(2)°, V = 5440(2) ų Z = 4. The geometry around the central metal atom could be considered as either a distortion from a capped octahedron with a carbonyl in a capping position or from a trigonal prism with the iodine capping a rectangular face. The solution behavior of Mo(CO)₂I₂(dppm)₂ was examined with ³¹P NMR, which showed it to be fluxional.     

Synthesis and X-ray crystal structure analysis of Fe2(CO)6(μ3-S)2Pd(bipy)

The reaction of Fe₂(CO)₆(μ-S₂),1 withbis(dibenzylideneacetone)-palladium, Pd(dba)₂, in the presence of 2,2′-bipyridine yielded the new compound Fe₂(CO)₆(μ ₃-S)₂Pd(bipy),2 in good yield (66%). Compound2 was characterized by IR,¹H NMR and single-crystal X-ray diffraction analyses. Compound2 contains a Pd(bipy) group that has been inserted into the S-S bond of1. Crystal data for2: space group P2₁/n,a=10.019(2) Å,b=25.414(5) Å,c=7.714(2) Å,β=90.26(2)°,Z=4, 1436 reflections,R=0.023.     

Further studies of M3(μ3-O)(μ-X)3(μ-O2CCH3)3L3 (M=Mo,W) type clusters with nine core electrons

Four new compounds having nine cluster electrons and cores of the types Mo₃OCl₃, Mo₃OBr₃, and W₃OCl₃ are reported. Compound (1) prepared by reduction of [Bu₄N][Mo₃OCl₆(OAc)₃] in THF with metallic zinc, was shown by X-ray crystallography to be Mo₃OCl₄(OAc)₃ (THF)₂ (1). It forms crystals in space groupP2₁ with unit cell dimensionsa=9.472(2) Å,b=13.546(4) Å,c=9.652(2) Å, =101.70(2)°,V=1201(1) Å₃,Z=2. The [Mo₃(₃-O)(-Cl)₃]⁴⁺ core is surrounded by three -O₂CCH₃ anions, one Cl^–, and two THF and has Mo-Mo distances of 2.620(1) Å, 2.613(1) Å, and 2.530(1) Å, with the shortest bond between the two Mo atoms to which the THF molecules are coordinated. Compounds [Bu₄N]₂ [Mo₃OBr₆(O₂CCH₃)₃] · Me₂CO, (2) and [Mo₃OBr₃(O₂CCH₃)₃(PMe₃)₃]₃ · BF₄, (3) are the first two nine-electron Mo₃ species with a [Mo₃(₃-O) Br₃]⁴⁺ core. Both were obtained by zinc reduction of [Mo₃OBr₆(O₂CCH₃)₃]^– in the presence of (NBu₄) Br (2) or PMe₃ and NaBF₄ (3), and each was characterized crystallographically. Compound (2) crystallized in space group Cc with unit cell dimensionsa=25.037(5) Å,b=12.827(2) Å,c=21.484(4) Å, =122.96(1)⁰,V=5790(3) ų,Z=4. While the anion has no crystallographically required symmetry, its virtual symmetry is C_3v . The Mo-Mo distances are 2.619(2) Å, 2.610(3) Å, 2.644(2) Å, with a mean value of 2.624[14] Å. Compound (3) crystallized in space groupP2₁/c with unit cell dimensionsa=10.846(2) Å,b=25.033(5) Å,c=12.641(5) Å, =94.74(2)⁰,V=3420(2) ų,Z=4. The cation occupies a general position but has virtual C_3v symmetry, with Mo-Mo distances of 2.601(2) Å, 2.610(2) Å, 2.627(2) Å, with a mean value of 2.613[14] Å. Thus the anionic and cationic Mo₃ clusters in (2) and (3), respectively, have average Mo-Mo distances that are equal within experimental error. Compound (4), [NEt₄]₂ [W₃OCl₆(O₂CCH₃)₃] is the first 9-electron compound of this type containing tungsten. It was prepared by reduction of [Et₄N][W₃OCl₆(OAc)₃] in benzene with Na/Hg. It crystallized in space groupP2₁2₁2₁ with unit cell dimensionsa=11.076(2) Å,b=14.345(2) Å,c=21.026(3) Å,V=3574(1) ų,Z=4. The anion resides on a general position but has virtual C_3v symmetry, with W-W distances of 2.577(1) Å, 2.612(1) Å, 2.584(1) Å and a mean value of 2.591[15] Å.     

Cleavage of 1,4-diphenylbuta-1,3-diyne on a ruthenium-cobalt cluster: Synthesis and molecular structure of Co2Ru3(μ4−C2Ph)(μ3−C2Ph)(μ-dppm)(μ-CO)2(CO)9

The reaction between Ru₃(₃-²-PhC₂C=CPh)(-dppm)(CO)₈ and Co₂(CO)₈ afforded dark red Co₂Ru₃(₄-C₂Ph)(₃-C₂Ph)(-dppm)(-CO)₂(CO)₉, shown by an X-ray structure determination to contain a strongly twisted Co₂Ru₃ bow-tie cluster (central Co), to which two PhC₂ units derived from cleavage of the original diyne are attached. One a these is strongly interacting with four metal atoms, the other being attached in the familiar ¹,2²-mode. The dppm ligand remains bridging two of the Ru atoms.     

Electrochemical oxidative addition of chloride to Rh2(μ-dppm)2(CO)2Cl2

The electrochemical oxidation of trans-Rh₂(μ-dppm)₂(CO)₂Cl₂ (dppm = bis (diphenylphosphino)methane) in the presence of chloride has afforded the new dirhodium(II) unsymmetrical complex Rh₂(μ-dppm)₂(μ-Cl)(CO)Cl₃ which is readily converted to the complex [Rh₂(μ-dppm)₂(μ-Co)(μ-Cl)Cl₂]PF₆. This species has been shown to undergo addition reactions with chloride to regenerate [Rh₂(μ-dppm)₂(μ-Cl)Cl₃(CO)], and with carbon monoxide and t-butylisocyanide to give the additional new dirhodium(II) complexes [Rh₂(μ-dppm)₂(μ-Cl)Cl₂(CO)₂]PF₆ and [Rh₂(μ-dppm)₂(μ-Cl)(CNC(CH₃)₃)₂Cl₂]PF₆, respectively. During prolonged exposure to carbon monoxide [Rh₂(μ-dppm)₂(μ-Co)(μ-Cl)Cl₂]PF₆ undergoes reduction with the loss of chloride to give [Rh₂(μ-dppm)₂(μ-Cl)(CO)₂]PF₆.     

Acetylene as a ligand on clusters: An accurate determination of the crystal and molecular structure of (Cp)2Ni2Fe(CO)3(μ3−C2H2) and of (CP)2Ni2Fe2(CO)6(μ4−C2H2)

Abstarct The Cp)₂Ni₂Fe(CO)₃(µ₃-C₂H₂) and Cp)₂Ni₂Fe(CO)₃(µ₃-C₂H₂) (B) complexes have been synthesized and spectroscopically characterized. An accurate X-ray study and a comparison with related structures shows that the substituents of the alkyne ligands exert considerable effects on the bonding parameters.Crystal data for complex A, monoclinic space group P2₁/n,a = 8.418(1),b = 15.779(2),c = 14,493(1) Å, = 91.64(1)°,Z = 4, 2753 observed reflections,R = 0.022; crystal data for complex B, monoclinic space group C2/c,a = 16.2189(7),b = 7.445(3),c = 25.745(5) Å, = 103.74(3),Z=8, 1853 observed reflections,R = 0.051.     

Synthesis and X-ray crystal structure of the electron-deficient metal carbonyl cluster [Os3(CO)5(μ3-H)(μ-H)(μ-PtBu2)2(μ-Ph2PCH2PPh2)]

The reaction of [Os₃(CO)₁₀(μ-dppm)] (1) with ^tBu₂PH in refluxing diglyme results in the electron-deficient metal cluster complex [Os₃(CO)₅(μ₃-H)(μ-P^tBu₂)₂(μ-dppm)] (2) (dppm = Ph₂PCH₂PPh₂) in good yields. The molecular structure of 2 has been established by a single crystal X-ray structure analysis. In contrast to the known homologue [Ru₃(μ-CO)(CO)₄(μ₃-H)(μ-H)(μ-P^tBu₂)₂(μ-dppm)] (3), no bridging carbonyl ligand was found in 2. The electronically unsaturated cluster 2 does not react with carbon monoxide under elevated pressure, therefore 2 seems to be coordinatively saturated by reason of the high steric demands of the phosphido ligands.     

Benzylidyne-capped group 9 trinuclear clusters: synthesis,structure and properties of trirhodium and cobalt–rhodium mixed-metal clusters [Co3 − nRhnCp3(μ3-CPh)2] (n=1,2,3)

The benzylidyne-capped trirhodium and cobalt–rhodium mixed-metal clusters [M₃Cp₃(μ₃-CPh)₂] (M₃: Rh₃, 1; CoRh₂, 2; Co₂Rh, 3) were synthesized. Complex 1 was prepared from [CpRh(CO)₂] and diphenylacetylene. Complexes 2 and 3 were synthesized by using a mixture of [CpRh(CO)₂] and [CpCo(CO)₂] and separated with silica-gel column chromatography. The molecular structures of 1, 2 and 3 were determined. The average RhRh distance (2.617(8) Å) in 2 is nearly equal to that in 1 (2.620(13) Å), and the average CoRh distance (2.503(16) Å) in 2 is similar to the average of the average CoCo (2.382(8) Å) length in [Co₃Cp₃(μ₃-CPh)₂] (4) and the average RhRh distance in 1. Clusters 2, 3 and 4 showed a chemically reversible one-electron oxidation and a chemically reversible one-electron reduction response in MeCN. For 1, a chemically reversible one-electron reduction and irreversible oxidation waves were observed in MeCN, whereas in CH₂Cl₂, two chemically reversible oxidation waves were observed. The oxidation and the reduction potentials shifted to more positive and more negative potential, respectively, with an increase of the number of rhodium atoms. The anionic radical of 3 was generated by the reaction with potassium metal in 2-methyltetrahydrofuran and was examined with ESR. The isotropic hyperfine coupling constant of the ⁵⁹Co nuclei of 3⁻ was slightly smaller than that of 4⁻. Geometry optimization of model complexes [M₃Cp₃(μ₃-CH)₂] (M₃: Rh₃, 1^′; CoRh₂, 2^′; Co₂Rh, 3^′) was carried out by a density functional theory (DFT) calculation. Assignments of low-energy UV–Vis absorption bands for 1 and 4 are proposed based on transitions of 1^′ and [Co₃Cp₃(μ₃-CH)₂] (4^′) calculated by time-dependent DFT.     

Reactions of metal carbonyl cluster complexes with multidentate phosphine ligands; preparation of bis(diphenylphosphino)methane derivatives of the trinuclear complexes M3(CO)12 (M = Fe,Ru and Os) and the X-ray crystal structure of Os3(CO)9(μ-dppm)(η1-dppm) (dppm = Ph2pch2ppH2)

The reaction of bis(diphenylphosphino)methane (dppm) with Fe₃(CO)₁₂ gave the known complexes Fe(CO)₄ (dppm), Fe₂(CO)₇ (dppm), in addition to Fe₂CO)₅(dppm)₂. Two new dppm derivatives of Ru₃CO)₁₂, Ru₃(CO)₉(μ-dppm)(η¹-dppm) and Ru₃(CO)₆(dppm)₃ have been isolated and spectroscopically characterised. From the reaction of Os₃(CO)₁₂ with dppm, the derivatives Os₃(CO)₁₀(dppm), Os₃(CO)₉(μ-dppm)(η¹-dppm) and Os₃(CO)₈(dppm)₂ have been isolated. The crystal structure of Os₃(CO)₉(μ-dppm)(η¹-dppm) has been determined.     

S2CPR3 adducts as bridging ligands in tricobalt clusters. X-Ray structure of [Co3(CO)7(μ3-CH)(μ-S2CPCy3)]

[Co₃(CO)₉(μ₃-CX)] (X  H, Cl) react with S₂CPR₃ (R  cyclohexyl, Cy or isopropyl, ⁱPr) in CH₂ Cl₂ to give heptacarbonyltricobalt clusters [CO₃(CO)₇(μ₃-CX)(μ₂-S₂CPR₃)] in which the S₂CPR₃ act as four-electron ligands, bridging a CoCo cluster edge in a σ(S), σ(S′) fashion, as shown by an X-ray determination on a crystal of the derivative with X  H, R  Cy. The five-membered CoSCSCo ring is nearly perpendicular to the CO₃ triangle (i.e. axial), in contrast to the equatorial disposition usually found in related complexes with phosphorus ligands.     

Unexpected preparation and X-ray crystal structure of the dinuclear complex Mo2(μ-P(O)(OCH3)2)2(CO)4(P(OCH3)3)2(CF3COO)2

Prolonged reaction of CF₃COOH with Mo(CO)₃(P(OCH₃)₃)₃ in CH₂Cl₂ yields the dimer [Mo(CO)₂(μ(O)P(OCH₃)₂)P(OCH₃)₃CF₃COO]₂ in low yield. The complex has been characterized by the usual spectroscopic methods and by an X-ray crystal structure determination. The molybdenum atoms are linked by two OP bridges, the six-membered dimetallacycle adopting a twisted-boat conformation. Each molybdenum is seven-coordinated and has a capped trigonal prism geometry, the capping position being occupied by an oxygen atom of the bridging OP(OCH₃)₂ group. A mechanism similar to the well-known Michaelis-Arbuzov rearrangement is proposed and substantiated by the concomitant apparition of CF₃COOCH₃ during the reaction.     

New triosmium–iridium clusters: Synthesis and molecular structure of [Os3Ir2(Cp1)2(μ-OH)(μ-CO)2(CO)8Cl] (1), [Os3IrCp1(μ-OH)(CO)10Cl] (2), [Os3IrCp1(μ-H)(μ-Cl)(η3,μ3-C5H2N(NH2)Br)(CO)9] (3) and [Os3IrCp1(μ-Cl)2(η2,μ3-C5H3N(NH)Br)(CO)7] (4)

The trinuclear osmium carbonyl cluster, [Os₃(CO)₁₀(MeCN)₂], is allowed to react with 1 equiv. of [IrCp¹Cl₂]₂ (Cp¹ = pentamethylcyclopentadiene) in refluxing dichloromethane to give two new osmium–iridium mixed-metal clusters, [Os₃Ir₂(Cp¹)₂(μ-OH)(μ-CO)₂(CO)₈Cl] (1) and [Os₃IrCp¹(μ-OH)(CO)₁₀Cl] (2), in moderate yields. In the presence of a pyridyl ligand, [C₅H₃N(NH₂)Br], however, the products isolated are different. Two osmium–iridium clusters with different coordination modes of the pyridyl ligand are afforded, [Os₃IrCp¹(μ-H)(μ-Cl)(η³,μ₃-C₅H₂N(NH₂)Br)(CO)₉] (3) and [Os₃IrCp¹(μ-Cl)₂ (η²,μ₃-C₅H₃N(NH)Br)(CO)₇] (4). All of the new compounds are characterized by conventional spectroscopic methods, and their structures are determined by single-crystal X-ray diffraction analysis.     

Synthesis and structure of three isomeric cluster complexes (μ-H)Os3μ-O2CC5H4Mn(CO)3(PPh3)2(CO)8

The reaction of (μ-H)Os₃μ-O₂CC₅H₄Mn(CO)₃(CO)₁₀ with PPh₃ in the presence of Me₃NO gave mono- and disubstituted heterometallic complexes (μ-H)Os₃μ-O₂CC₅H₄Mn(CO)₃(PPh₃)(CO)₉ and (μ-H)Os₃μ-O₂CC₅H₄Mn(CO)₃ (PPh₃)₂(CO)₈. Crystal structure determination was performed for three isomeric cluster complexes (μ-H)Os₃μ-O₂CC₅H₄Mn(CO)₃(PPh₃)₂(CO)₈, which are both geometrical and conformational isomers differing in color. The geometrical isomerism is due to the attachment of the PPh₃ group at different vertices of the Os₃ triangle relative to the O₂CC₅H₄Mn(CO)₃ bridging ligand. The conform ational isomerism implies that the molecules have the same arrangement of ligands and differ only in the values of bond angles between the planar fragments of the clusters.     

Further studies of the reactions of PtRu5(μ6-C)(CO)16 with alkynes: The preparation and structural characterizations of PtRu5(CO)13(μ-EtC2Et)(μ3-EtC2Et)(μ5-C) and Pt2Ru6(CO)17(μ-η5-Et4C5)(μ3-EtC2Et) (μ6-C)

The reaction of PtRu₅(CO)₁₆(μ₆-C),1 with 3-hexyne in the presence of UV irradiation produced two new electron-rich platinum-ruthenium cluster complexes PtRu₅(CO)₁₃(μ-EtC₂Et)(μ₃-EtC₂Et)(μ₅-C),2 (20% yield) and Pt₂Ru₆(CO)₁₇(μ-η⁵-Et₄C₅)(μ₃-EtC₂Et) (μ₆-C),3 (7% yield). Both compounds were characterized by single-crystal X-ray diffraction analyses. Compound2 contains of a platinum capped square pyramidal cluster of five ruthenium atoms with the carbido ligand located in the center of the square pyramid. A EtC₂Et ligand bridges one of the PtRu₂ triangles and the Ru-Pt bond between the apical ruthenium atom and the platinum cap. The structure of compound3 consists of an octahedral PtRu₅ cluster with an interstitial carbido ligand and a platinum atom capping one of the PtRu₂ triangles. There is an additional Ru(CO)₂ group extending from the platinum atom in the PtRu₅ cluster that contains a metallated tetraethylcyclopentadienyl ligand that bridges to the platinum capping group. There is also a EtC₂Et ligand bridging one of the PtRu₂ triangular faces to the capping platinum atom. Compounds2 and3 both contain two valence electrons more than the number predicted by conventional electron counting theories, and both also possess unusually long metal-metal bonds that may be related to these anomalous electron configurations. Crystal data for2, space group Pna2₁,a=19.951(3) Å,b=9.905(2) Å,c=17.180(2) Å,Z=2, 1844 reflections,R=0.036; for3, space group Pna2₁,α=13.339(1) Å,b=14.671(2) Å,c=11.748(2) Å, α=100.18(1)°, β=95.79(1)°, γ=83.671(9)°,Z=2, 3127 reflections,R=0.026.     

Energetics and structure in I 2 − (CO2) n clusters

We have implemented a model of I ₂ ^? (CO₂) _n (2 ≤n ≤ 17) clusters and present an analysis of the minimum energy structures obtained from a quenching procedure. A discussion of the importance of various potential contributions to the energetics of the clusters is also presented. Given the current state of understanding of structural control of caging and the time scales of recombination and evaporation, this model has important implications for understanding the picosecond dynamics observed by the Lineberger group and for rigorous studies of evaporation rates.