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.     

Cluster synthesis. 42. The synthesis and crystal and molecular structures of the sulfur-bridged platinum-ruthenium carbonyl cluster compounds PtRu3(CO)9 L(PPh3)(μ3-S)2 (L=CO,PPh3) and PtRu4(CO)12(PPh3)(μ4-S)2

Two new mixed metal cluster complexes PtRu₃(CO)₁₀(PPh₃)(₃-S)₂,3 14% yield and PtRu₃(CO)₉(PPh₃)₂(₃-S)₂,4 23% yield were obtained from the reaction of Ru₃(CO)₉(₃-S)₂,1 with Pt(PPh₃)₂(C₂H₄) at 0°C. The cluster of4 consists of a spiked triangle of four metal atoms with two triply bridging sulfido ligands. The reaction of Ru₄(CO)₁₁(₄-S)₂,2 with Pt(PPh₃)₂(C₂H₄) yielded the expanded mixed-metal cluster complex PtRu₄(CO)₁₂(PPh₃)(₄-S)₂,5 in 12% yield. The structure of the cluster5 can be described as a pentagonal bipyramid of five metal atoms and two sulfido ligands with one metal-metal bond missing. Compounds4 and5 were characterized by a single-crystal X-ray diffraction analyses.     

New electron-deficient alkene and alkyne derivatives of Ru5(μ5-C)(CO)15: The syntheses and crystal structure analyses of Ru5(μ5-C)(CO)13 [C2H2(CO2Me)2] and Ru5(μ5-C)(CO)15 [C2(CO2Me)2]

Treatment of carbido cluster Ru₅(μ ₅-C)(CO)₁₅ with Me₃NO in acetonitrile solution followed by addition of dimethyl maleate or dimethyl acetylene dicarboxylate affords new clusters Ru₅(μ ₅-C)(CO)₁₃[C₂H₂(CO₂Me)₂] (1) and Ru₅(μ ₅-C)(CO)₁₅[C₂(CO₂Me)₂] (2), respectively. Single crystal X-ray structural studies reveal that both complexes contain a wingtip-bridged butterfly pentametallic skeleton. In complex1 the maleate fragment is coordinated to one wingtip Ru atom through its carbon-carbon double bond and to the adjacent Ru atom by the formation of two O → Ru dative bonding interactions, while the acetylene dicarboxylate fragment in2 is best considered as acis-dimetallated alkene, linking one hinge Ru atom and the nearby Ru atom at the bridged position. Crystal data for1: space group P 4₂/n;a=20.199(6),c=13.941(3) Å,Z=8; finalR _F=0.025,R _w=0.026 for 3963 reflections withI>2σ(I). Crystal data for2: space group P2₁/n;a=9.634(3),b=20.062(6),c=17.372(5) Å,β=90.62(2)°,Z=4; finalR _F=0 033,R _w=0.036 for 4683 reflections withI>3σ(I).     

Synthesis of Platinum-Triruthenium Clusters Using the Zero-Valent Platinum Reagent Pt(nb)3: X-Ray Crystal Structures of Ru3Pt(CO)11(P-iPr3)2, Ru3Pt(μ-H)(μ3-η3-MeCCHCMe)(CO)9(P-iPr3), Ru3Pt(μ3-η2-PhCCPh)(CO)10(P-iPr3), Ru3Pt(μ-H)(μ4-N)(CO)10(P-iPr3) and Ru3Pt(μ-H)(μ4-η2-NO)(CO)10(P-iPr3)

The complexes Pt(nb)_3-n(P-iPr₃)_n (n=1, 2, nb=bicyclo[2.2.1]hept-2-ene), prepared in situ from Pt(nb)₃, are useful reagents for addition of Pt(P-iPr₃)_n fragments to saturated triruthenium clusters. The complexes Ru₃Pt(CO)₁₁(P-iPr₃)₂ (1), Ru₃Pt(-H)(₃-³-MeCCHCMe)(CO)₉(P-iPr₃) (2), Ru₃Pt(₃-²-PhCCPh)(CO)₁₀(P-iPr₃) (3), Ru₃Pt(-H)(₄-N)(CO)₁₀(P-iPr₃) (4) and Ru₃Pt(-H)(₄-²-NO)(CO)₁₀(P-iPr₃) (5) have been prepared in this fashion. All complexes have been characterized spectroscopically and by single crystal X-ray determinations. Clusters 1–3 all have 60 cluster valence electrons (CVE) but exhibit differing metal skeletal geometries. Cluster 1 exhibits a planar-rhomboidal metal skeleton with 5 metal–metal bonds and with minor disorder in the metal atoms. Cluster 2 has a distorted tetrahedral metal arrangement, while cluster 3 has a butterfly framework (butterfly angle=118.93(2)°). Clusters 4 and 5 posseses 62 CVE and spiked triangular metal frameworks. Cluster 4 contains a ₄-nitrido ligand, while cluster 5 has a highly unusual ₄-²-nitrosyl ligand with a very long nitrosyl N–O distance of 1.366(5) Å.     

Cluster Chemsitry. 96. Penta- and hexa-nuclear ruthenium cluster complexes derived from reactions of cyclopentadienes with Ru5(μ5-C2PPh2)(μ-PPh2)(CO)13

The reactions between Ru₅( ₅-C₂PPh₂)(gm-PPh₂(CO)₁₃ (1) and cyclopentadienes afforded the hexanuclear clusters Ru₆( ₆-C)( ₃-PPh₂)₂(CO)₁₀(-C₅ R ₅) [R ₅ = H₅ (2), H₄Me (3), Me₅ (4)] which contain an encapsulated carbide and a face-capping ₃-CH group, formed by cleavage of CC and CP bonds of the C₂PPh₂ moiety in1. In the reaction with cyclopentadiene, the unusual ligand C₁₃H₁₂O, formed by combination of C₂, CO and two molecules of C₅H₆ (or one molecule of dicyclopentadien), was characterized in the complex Ru₅( ₄-PPh) ( ₄-C₁₃H₁₂O)(-PPh₂(CO)₁₁(-C₅H₅) (5). In the reaction with pentamethylcyclopentadiene, the vinylidene complex Ru₅( ₃-CCHPh)( ₄-PPh)( ₄-PPh) (-PPh₂)(CO)₉(-C₅Me₅) (6) was also formed.     

Cluster Complexes of Polythioether Macrocycles: The Synthesis and Molecular Structures of Ru6(CO)13(cis-SCH2 CHMe(CH2SCH2CHMe)2CH2)(μ6-C) and Ru6(CO)13(trans-SCH2 CHMe(CH2SCH2CHMe)2CH2)(μ6-C)

The reaction of a mixture of cis-3,7,11-trimethyl-1,5,9-trithiacyclododecane, cis-Me₃12S3, 1 and trans-3,7,11-trimethyl-l,5,9-trithiacyclododecane, trans-Me₃12S3, 2, with Ru₆(CO)₁₇(μ ₆-C), 3, yielded three new cluster compounds Ru₆(CO)₁₃(μ-η³-cis-SCH₂CHMe(CH₂SCH₂CHMe)₂CH₂)(μ ₆-C) 4, and two isomers of Ru₆(CO)₁₃(μ-η³-cis-SCH₂CHMe(CH₂SCH₂CHMe)₂CH₂)(μ ₆-C) 5a and 5b. The molecular structures of 4 and 5b were established by single crystal X-ray diffraction analyses. In both complexes, the macrocycles have adopted tridentate coordination with one of the sulfur atoms in a bridging position. Two carbonyl ligands occupy bridging positions in each compound. Crystal Data for 4·Me₂CO: space group=P2₁/n, a=11.295(1) Å, b=17.547(3) Å, c=20.318(3) Å, β=93.71(1)°, Z=4, 2900 reflections, R=0.025. Crystal Data for 5b·1.5 C₆H₆: space group=Pbca, a=31.8900(8) Å, b=23.4330(6) Å, c=21.6240(4) Å, Z=16, 12163 reflections, R=0.040.     

The reaction of [Ru10C(CO)24][ppn]2 with carbon monoxide to yield [Ru3(CO)12] and [Ru6C(CO)16]2−

The dianion [Ru₁₀C(CO)₂₄]²⁻ in CH₂Cl₂ reacts with CO under ambient conditions to produce quantitative amounts of the species [Ru₃(CO)₁₂] and [Ru₆C(CO)₁₆]²⁻; the hydrido-anion [HRu₁₀C(CO)₂₄]⁻ reacts similarly to form [Ru₆C(CO)₁₆]⁻.     

Vibrational spectra of metal cluster complexes containing the methylidyne ligand. H3Ru3(μ3-CH)(CO)9 and H3Ru3(μ-CCl)(CO)9

Vibrational spectra of the metal cluster complexes H₃Ru₃(μ₃-CH)(CO)₉ and H₃Ru₃(μ₃-CCl)(CO)₉ have been measured and the vibrations of the central (μ₃-CY)Ru₃ groupings assigned. The spectra are consistent with approximate C_3v symmetry of the cluster units in the crystal. Approximate normal-coordinate analyses have been carried out for the (μ₃-CY)Ru₃ molecular fragments and the derived force constant values are compared with those obtained in similar analyses of the analogous cobalt cluster species.     

Comparison of the Bonding of Benzene and C60 to a Metal Cluster: Ru3(CO)9(μ3-η2,η 2,η2-C6H6) and Ru3(CO)9(μ3-η2,η2,η2-C60)

The electron distributions and bonding in Ru₃(CO)₉( ³- ², ², ²-C₆H₆) and Ru₃(CO)₉( ³- ², ², ²-C₆₀) are examined via electronic structure calculations in order to compare the nature of ligation of benzene and buckminsterfullerene to the common Ru₃(CO)₉ inorganic cluster. A fragment orbital approach, which is aided by the relatively high symmetry that these molecules possess, reveals important features of the electronic structures of these two systems. Reported crystal structures show that both benzene and C₆₀ are geometrically distorted when bound to the metal cluster fragment, and our ab initio calculations indicate that the energies of these distortions are similar. The experimental Ru–C_fullerene bond lengths are shorter than the corresponding Ru–C_benzene distances and the Ru–Ru bond lengths are longer in the fullerene-bound cluster than for the benzene-ligated cluster. Also, the carbonyl stretching frequencies are slightly higher for Ru₃(CO)₉( ³- ², ², ²-C₆₀) than for Ru₃(CO)₉( ³- ², ², ²-C₆H₆). As a whole, these observations suggest that electron density is being pulled away from the metal centers and CO ligands to form stronger Ru–C_fullerene than Ru–C_benzene bonds. Fenske-Hall molecular orbital calculations show that an important interaction is donation of electron density in the metal–metal bonds to empty orbitals of C₆₀ and C₆H₆. Bonds to the metal cluster that result from this interaction are the second highest occupied orbitals of both systems. A larger amount of density is donated to C₆₀ than to C₆H₆, thus accounting for the longer metal–metal bonds in the fullerene-bound cluster. The principal metal–arene bonding modes are the same in both systems, but the more band-like electronic structure of the fullerene (i.e., the greater number density of donor and acceptor orbitals in a given energy region) as compared to C₆H₆ permits a greater degree of electron flow and stronger bonding between the Ru₃(CO)₉ and C₆₀ fragments. Of significance to the reduction chemistry of M₃(CO)₉( ³- ², ², ²-C₆₀) molecules, the HOMO is largely localized on the metal–carbonyl fragment and the LUMO is largely localized on the C₆₀ portion of the molecule. The localized C₆₀ character of the LUMO is consistent with the similarity of the first two reductions of this class of molecules to the first two reductions of free C₆₀. The set of orbitals above the LUMO shows partial delocalization (in an antibonding sense) to the metal fragment, thus accounting for the relative ease of the third reduction of this class of molecules compared to the third reduction of free C₆₀.     

Novel μ2-oxo-bridged dinuclear aryltelluronic triorganotin(IV) esters: syntheses,structural characterizations,and in vitro cytotoxicity

Four new μ₂-oxo-bridged dinuclear aryltelluronic triorganotin esters [ArTe(μ-O)(OH)(OSnR₃)₂]₂ (Ar?=?n-propyl-Ph, R?=?Me: 1, R?=?Ph: 2; Ar?=?i-propyl-Ph, R?=?Me: 3, R?=?Ph: 4) were synthesized by reaction of μ₂-oxo-bridged dinuclear aryltelluronic acids and the corresponding R₃SnCl (R?=?Me, Ph) with potassium hydroxide in methanol. The complexes were characterized by X-ray crystallography, elemental analysis, FT-IR, and NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopy. The structural analysis indicates that these complexes are isostructural and crystallized as Sn₄Te₂ molecules, in which the asymmetric four-membered Te₂(μ₂-O)₂ units are situated in the center. The geometry of tellurium is described as a distorted octahedron and each tin is described as a distorted tetrahedron. Complex 2 has a 2-D network structure connected by intermolecular C–H?π interactions. Complexes 1–4 were tested for in vitro cytotoxicity against human lung cancer cells (A549) and human hepatocellular carcinoma cells (HepG2).     

The Synthesis of the Arene Clusters Ru6C(CO)14(η6-Arene) (Arene = C6H5CHMe2, C6H5C4H9, C6H5C3H7, and C6H5C3H5)

On reaction with Ru₃(CO)₁₂, isopropenylbenzene and 4-phenyl-l-butene undergo hydrogenation, to yield the clusters, Ru₆C(CO)₁₄(⁶-C₆H₅CHMe₂) 1 and Ru₆C(CO)₁₄(⁶-C₆H₅C₄H₉) 2, respectively. With allylbenzene, both hydrogenation and isomerization occurs affording Ru₆C(CO)₁₄(⁶-C₆H₅C₃H₇) 3 and Ru₆C(CO)14(⁶-C₆H₅C₃H₅) 4. The structures of 1 and 2 have been established by single crystal X-ray diffraction. One of the Ru–Ru bond lengths in 2 is unusually long and extended Hückel molecular orbital calculations have been used in an attempt to rationalize this feature.     

Reaction of [η 5:σ-Me2C(C5H4)(C2B10H10)]Ru(NCCH3)2 with internal alkynes: Synthesis and structural characterization of ruthenium-cyclobutadiene and ruthenacyclopentatriene complexes

Reaction of [η ⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru(NCCH₃)₂ (1) with R¹C≡CR¹(R¹ = Et, Ph) in toluene at 80°C yielded organoruthenium cyclobutadiene complexes [η ⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru(η ⁴-C₄R ₄ ¹ ) in >80% yield. Treatment of 1 with diynes R₂C≡C(CH₂)₃C≡CR² (R² = Me, Et) in toluene at room temperature yielded ruthenacyclopentatrienes [η ⁵:σ-Me₂C (C₅H₄)(C₂B₁₀H₁₀)]Ru[=C₂(R²)₂C₂(CH₂)₃] in >85% yield. These new complexes were fully characterized by various spectroscopic techniques, elemental analyses and single-crystal X-ray diffraction studies. The possible reaction mechanism was proposed.     

New Mixed Metal Cluster Complexes Containing Platinum. The Synthesis and Structural Characterizations of PtFe4(CO)12(COD)(μ5-C) and PtFe4(CO)12(PMe2Ph)2(μ5-C)

The new mixed metal carbide containing cluster compounds PtFe₄(CO)₁₂(COD)(₅-C) 1 and PtFe₄(CO)₁₂(PMe₂Ph)₂(₅-C), 2 were obtained by metal–metal exchange reactions between [Et₄N]₂[Fe₅(C)(CO)₁₄] with Pt(COD)Cl₂ in the presence of TIPF₆ and Pt(PMe₂Ph)₂Cl₂, respectively. Compound 1 was also obtained by the reaction of Fe₅(CO)₁₅(₅-C) with Pt(COD)₂ in the presence of UV irradiation but in a lower yield. Both compounds were characterized by a combination of IR, ¹H NMR and single crystal x-ray diffraction analyses. Both complexes consists of a square pyramidal cluster of five metal atoms with an interstitial carbido ligand in the center of the square base. The phosphine ligands in 2 undergo a dynamical intramolecular interchange at a rate that is fast on the ¹H NMR time scale at 45°C, G (at 318 K)=15.1 kcal/mol.     

The synthesis and structural characterisation of [IrCl(COD)(PEt3) n ], n = 1 or 2, and orthometallated Vaska's compound, [IrHCl(CO)(PPh3)η 2-PPh2(C6H4)]

Two iridium(I) complexes, [IrCl(COD)(PEt₃) _n ], n = 1 or 2, have been prepared and structurally characterised. Although [IrCl(COD)(PEt₃)] is a known compound the spectroscopic data on both compounds is presented and discussed. In addition, the X-ray crystal structure of the previously described orthometallated isomer of Vaska's compound, [IrHCl(CO)(PPh₃) ²-PPh₂(C₆H₄)], is reported to show the hydride ligand trans- to the carbonyl ligand.     

Electrochemical and Photochemical Conversion of [Ru3Ir(μ 3-H)(CO)13] into [Ru3Ir(μ-H)3(CO)12]

Electrochemical and photochemical properties of the tetrahedral cluster [Ru₃Ir( ₃-H)(CO)₁₃] were studied in order to prove whether the previously established thermal conversion of this cluster into the hydrogenated derivative [Ru₃Ir(-H)₃(CO)₁₂] also occurs by means of redox or photochemical activation. Two-electron reduction of [Ru₃Ir( ₃-H)(CO)₁₃] results in the loss of CO and concomitant formation of the dianion [Ru₃Ir( ₃-H)(CO)₁₂]^2–. The latter reduction product is stable in CH₂Cl₂ at low temperatures but becomes partly protonated above 283K into the anion [Ru₃Ir(-H)₂(CO)₁₂]^– by traces of water. The dianion [Ru₃Ir( ₃-H)(CO)₁₂]^2– is also the product of the electrochemical reduction of [Ru₃Ir(-H)₃(CO)₁₂] accompanied by the loss of H₂. Stepwise deprotonation of [Ru₃Ir(-H)₃(CO)₁₂] with Et₄NOH yields [Ru₃Ir(-H)₂(CO)₁₂]^– and [Ru₃Ir( ₃-H)(CO)₁₂]^2–. Reverse protonation of the anionic clusters can be achieved, e.g., with trifluoromethylsulfonic acid. Thus, the electrochemical conversion of [Ru₃Ir( ₃-H)(CO)₁₃] into [Ru₃Ir(-H)₃(CO)₁₂] is feasible, demanding separate two-electron reduction and protonation steps. Irradiation into the visible absorption band of [Ru₃Ir( ₃-H)(CO)₁₃] in hexane does not induce any significant photochemical conversion. Irradiation of this cluster in the presence of CO with _irr>340nm, however, triggers its efficient photofragmentation into reactive unsaturated ruthenium and iridium carbonyl fragments. These fragments are either stabilised by dissolved CO or undergo reclusterification to give homonuclear clusters. Most importantly, in H₂-saturated hexane, [Ru₃Ir( ₃-H)(CO)₁₃] converts selectively into the [Ru₃Ir(-H)₃(CO)₁₂] photoproduct. This conversion is particularly efficient at _irr >340nm.     

Octahedral bis(acetylide) and bis(diacetylide) complexes of ruthenium(II) with linear C2MC2 and C4MC4 chains: The first X-ray structures of the all trans bis(acetylides) Ru(CO)2(CCPh)2(PEt3)2 and Ru(CO)2(CCH)2(PEt3)2

Bis(acetylides) and bis(diacetylides) of ruthenium(II), trans-Ru(CO)₂(PEt₃)₂(CCR)₂ (1) (1a, R  Ph; 1b, R  ^tBu; 1c, R  SiMe₃; 1d, R  H) and trans-Ru(CO)₂(PEt₃)₂(CCC CR)₂ (2) (2a, R  SiMe₃; 2b, R  H) have been synthesized and characterised. The first single crystal X-ray analyses of these all trans-acetylides have revealed linear C₂RuC₂ chains in 1a and 1d.     

Reactions of the Cluster Anion [HRu3(CO)11)]− with Dicyclohexylphosphine: Synthesis and Molecular Structure of H2Ru3(CO)8(PCy2)2 and H2Ru3(CO)6(PCy2)2(HPCy2)2

The cluster anion [HRu₃(CO)₁₁]^- (1) reacts with dicyclohexylphosphine in THF solution to give the anionic derivative [HRu₃(CO)₈(PCy₂)₂]^- (2), protonation of which yields the neutral cluster H₂Ru₃(CO)₈(PCy₂)₂ (3) and, in the presence of excess phosphine, HRu₃(CO)₇(PCy₂)₃ (4). In protic methanol as reaction medium, the reaction of 1 with HPCy₂ gives directly the neutral complex H₂Ru₃(CO)₆(PCy₂)₂(HPCy₂)₂ (5), together with 4. The single-crystal structure X-ray analysis of 3 shows a closed triangular Ru₃ framework. The electron count is in accordance with the EAN rule, but the structure analysis of 5 reveals an open, almost linear Ru₃ skeleton, which is electron-deficient with respect to the EAN rule.     

C60Ru(OCOCF3)(CO)(PPh3)配合物的合成及性能

富勒烯;钌配合物;循环伏安法;C60Ru(OCOCF3)(CO)(PPh3)配合物的合成及性能     

Syntheses, X-ray structural characterizations, and thermal stabilities of two nonclassical trinuclear vanadium(IV) complexes, (V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6(H2O) and (V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6(py), and polymeric complexes of stoichiometry (VO(O2PR2)2)∞, R2 = Ph2 and o-(CH2)2(C6H4)

The preparation and structural characterization of two trinuclear vanadium complexes, (V(3)(μ(3)-O)O(2))(μ(2)-O(2)P(CH(2)C(6)H(5))(2))(6)(H(2)O), 1, and (V(3)(μ(3)-O)O(2))(μ(2)-O(2)P(CH(2)C(6)H(5))(2))(6)(py), 2, are reported. In these nonclassical structures, the planar central core consists of the three vanadium atoms arranged in the form of an acute quasi-isosceles triangle with the central oxygen atom multiply bonded to the vanadium atom at the center of the vertex angle and weakly interacting with the two other vanadium atoms on the base sites, each of which contain one external multiply bonded oxygen atom. Reacting VO(acac)(2)in the presence of diphenylphosphinic acid affords (VO(O(2)PPh(2))(2))(∞), 3, while 2-hydroxyisophosphindoline-2-oxide at room temperature in CH(2)Cl(2) affords ((H(2)O)VO(O(2)Po-(CH(2))(2)C(6)H(4))(2))(∞), 4, and at 120 °C in EtOH yields (VO(O(2)P(o-(CH(2))(2)(C(6)H(4)))(∞), 5 on the basis of elemental analyses. The thermal and chemical stability of the complexes were assessed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) measurements. The bond strengths of the vanadium atoms to the OH(2) ligand in 1 and to the NC(5)H(5) ligand in 2 were assessed at 10.7 and 42.0 kJ/mol respectively. Room temperature magnetic susceptibility measurements reveal magnetic moments for trinuclear 1 and 2 at 3.02(1) and 3.05(1) μ(B/mol), and also close to spin only values (1.73 μ(B)) values for 3, 4, and 5 at 1.77(2), 1.758(7), and 1.77(3) μ(B), respectively. Variable-temperature, solid-state magnetic susceptibility measurements were conducted on complex 2 in the temperature range of 2.0-298 K and at an applied field of 0.5 T. Magnetization measurements at 2 and 4 K confirmed a very weak magnetic interaction between the vanadyl centers.     

Interconversion of acetyl- and terminal-carbonyl groups on labeled (η5-indenyl)(CO)2Fe13C(O)CH3

The ¹³C-labeled (95–99%) acetyl complex (η⁵-In)(CO)₃Fe¹³C(O)CH₃ (8) (In = indenyl) has been prepared by acylating In(CO)₂Fe⁻ Na⁺ (1) with CH₃ ¹³C(O)Cl. All of the starting 1 must be consumed in this reaction (at −78°C), or 45% of the product results as In(CO)(¹³CO)FeC(O)CH₃ (9). Once isolated, neither 8 nor mixtures of 8 and 9 further redistribute or lose this label after pressurizing under 800 atm CO, or after heating in heptane, THF, or acetonitrile solution. Treating 8 with even trace amounts of 1 or of Cp(CO)₂Fe⁻ Na⁺ (5) rapidly interconverts the acetyl and terminal carbonyls, thus transforming 8 into mixtures of 8 and 9. A mechanism is proposed that involves a labile metalla-β-diketonate In(CO)Fe(Fp-CO)(CH₃¹³CO)⁻ Na⁺.