Reactions of the dichloroboryl complex of osmium, Os(BCl2)Cl(CO)(PPh3)2, with water, alcohols, and amines: Crystal structures of Os[B(OH)2]Cl(CO)(PPh3)2, Os[B(OEt)2]Cl(CO)(PPh3)2, and

[Cp₄Fe₄(CO)₄] (1) reacts with p-BrC₆H₄Li and MeOH in sequence to afford the functionalized cluster [Cp₃Fe₄(CO)₄(C₅H₄-p-C₆H₄Br)] (2), while the reaction of 2 with n-BuLi and MeOH produces [Cp₂Fe₄(CO)₄(C₅H₄Bu)(C₅H₄-p-C₆H₄Br)] (3). The double cluster [Cp₃Fe₄(CO)₄(C₅H₄)]₂(p-C₆H₄) (4) has been prepared by treatment of [Cp₄Fe₄(CO)₄] with p-C₆H₄Li₂ and MeOH in sequence. The electrochemistry of 2 and 4, as well as the crystal structure of 4 have been investigated.     

Synthesis and crystal structure of the double cluster [Cp3Fe4(CO)4(C5H4)]2(p-C6H4)

[Cp₄Fe₄(CO)₄] (1) reacts with p-BrC₆H₄Li and MeOH in sequence to afford the functionalized cluster [Cp₃Fe₄(CO)₄(C₅H₄-p-C₆H₄Br)] (2), while the reaction of 2 with n-BuLi and MeOH produces [Cp₂Fe₄(CO)₄(C₅H₄Bu)(C₅H₄-p-C₆H₄Br)] (3). The double cluster [Cp₃Fe₄(CO)₄(C₅H₄)]₂(p-C₆H₄) (4) has been prepared by treatment of [Cp₄Fe₄(CO)₄] with p-C₆H₄Li₂ and MeOH in sequence. The electrochemistry of 2 and 4, as well as the crystal structure of 4 have been investigated.     

Hetero- and homo-nuclear bimetallic ruthenol complexes by dehydrogenative metallacyclization of Ru(CO)3(bi-1,7-cyclooctadienyl), preparation and x-ray structure of Fe(CO)3(C16H22), RuFe(CO)6(C16H22) and Ru2(CO)6(C16H20)

The reaction of M₃(CO)₁₂ (M = Ru, Fe) with excess bi-2,7-cyclooctadienyl (C₁₆H₂₂) 1 gave a mononuclear complex M(CO)₃(1,2,1′-2′-η⁴-C₁₆H₂₂), 2a (M = Ru) or 3a (M = Fe), in good yield. Treatment of 2a with Fe₃(CO)₁₂ or reaction of 3a with Ru₃(CO)₁₂ gave the heterobimetallic complex RuFe(CO)₆(C₁₀H₂₂) consisting of a ruthenacyclopentadiene unit coordinated to an Fe(CO)₃ fragment, as confirmed by ¹H NMR and X-ray studies. The corresponding homobimetallic complex Ru₂(CO)₆(C₁₆H₂₂) was obtained from the 1:1 reaction of 2a with Ru₃(CO)₁₂, while the direct reaction of 1 with Ru₃(CO)₁₂ gave Ru₂(CO)₆(C₁₆H₂₀) preferentially with a loss of two hydrogen atoms. The pathway for formation of these bimetallic complexes was interpreted as a dehydrogenative metallacyclization followed by hydrogen transfer.     

The structure and formation of niobocene carbonyl heteronuclear derivatives. The molecular structures of Cp2Nb(CO)(μ-CO)Mn(CO)4, Cp2Nb(CO)(μ-H)Ni(CO)3 and [Cp2Nb(CO)(μ-H)]2Mo(CO)4

The heteronuclear Cp₂Nb(CO)(μ-CO)Mn(CO)₄ (I), Cp₂Nb(CO)(μ-H)Ni(CO)₃ (II) and [Cp₂Nb(CO)(μ-H)]₂M(CO)₄ (III, M = Mo;IV, M = W) complexes were prepared by reaction of Cp₂NbBH₄/Et₃N with Mn₂(CO)₁₀ in refluxing toluene, direct reaction of Cp₂NbBH₄ with Ni(CO)₄ in ether, and reaction of Cp₂NbBH₄/Et₃N with M(CO)₅. THF complexes (M = Mo or W) in THF/benzene mixture. An X-ray investigation of compounds I–III was performed. It is established that in I the bonding between Mn(CO)₅ and Cp₂Nb(CO) (with the angle (α) between the ring planes being 44.2(5)°) fragments takes place via a direct NbMn bond (3.176(1) Å) and a highly asymmetric carbonyl bridge (MnC_co 1.837(5) Å, NbC_co 2.781(5) Å). On the other hand, in complex II the sandwich Cp₂Nb(CO)H molecule (angle α = 37.8°) is combined with the Ni(CO)₃ group generally via a hydride bridge (NbH 1.83 Å, NiH 1.68 Å, NbHNi angle 132.7°) whereas the large Nb?Ni distance, 3.218(1) Å, shows the weakening or even absence of the direct NbNi bond. Similarly, in complex III two Cp₂Nb(CO)H molecules (with α angles equal to 41.4 and 43.0°, respectively) are joined to the Mo(CO)₄ group via the hydride bridges (NbH 1.83 and 1.75 Å and MoH 2.04 and 2.06 Å) producing a cis-form. The direct NbMo bonds are probably absent, since the Nb?Mo distances are rather long (3.579 and 3.565 Å). The effect of electronic and steric factors on the structure of heteronuclear niobocene carbonyl derivatives is discussed.     

Übergangsmetall-substituierte acylphosphane und phosphaalkene : XX. Dipolare [3 + 2]-Cycloadditionen eines acetylendicarbonsäureesters an die metallophosphaalkene (η-C5Me5)(CO)2Fe---P=C(R)SiMe3 (R = Ph, SiMe3)

The metallo-phosphaalkenes (η⁵-C₅Me₅)(CO)₂FeP=C(R)(SiMe₃) (Ia: R = SiMe₃, Ib: R = Ph) and MeO₂C---CC---CO₂Me undergo a dipolar [3+2]-cycloaddition to afford the metallo-heterocycles [(η⁵-C₅Me₅)(CO)

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=C(R)SiMe₃] (IIIa,b) with exocyclic P=C double bonds.     

A new and unusual isomerism in [Fe(CO)2 {P(OR)3}2 (SO2)] complexes (R = aryl)

[Fe(CO)₂ {P(OR)₃}₂ (SO₂)] complexes (R = aryl) exist in solution as equilibrium mixtures of two isomers; both have been shown by X-ray diffraction studies (where R = Ph or o-MeC₆H₄) to have planar coordination about SO₂ and trigonal bipyramidal coordination about Fe, but in one isomer (R = Ph) the equatorial plane is occupied by SO₂ and two CO ligands whilst in the other one (R = o-MeC₆H₄) it is occupied by the SO₂ and two P ligands.     

Coordinating properties of [M(CO)5(CN)] [M=Cr; Mo; W] ligands: formation of ion pairs or dinuclear cyanide-bridged complexes, spectroscopic and X-ray diffraction studies

The reaction of sodium cyanopentacarbonylmetalates Na[M(CO)₅(CN)] (M=Cr; Mo; W) with cationic Fe(II) complexes [Cp(CO)(L)Fe(thf)][O₃SCF₃], [L=PPh₃ (1a), CN-Benzyl (1b), CN-2,6-Me₂C₆H₃ (1c); CN-Bu^t (1d), P(OMe)₃ (1e), P(Me)₂Ph (1f)] in acetonitrile solution, yielded the metathesis products [Cp(CO)(L)Fe(NCCH₃)][NCM(CO)₅] [M=W, L=PPh₃ (2a), CN-Benzyl (2b), CN-2,6-Me₂C₆H₃ (2c); CN-Bu^t (2d), P(OMe)₃ (2e), P(Me)₂Ph (2f); M=Cr, L=(PPh₃) (3a), CN-2,6-Me₂C₆H₃ (3c); M=Mo, L=(PPh₃) (4a), CN-2,6-Me₂C₆H₃ (4c)]. The ionic nature of such complexes was suggested by conductivity measurements and their main structural features were determined by X-ray diffraction studies. Well-resolved signals relative to the [M(CO)₅(CN)] moieties could be distinguished only when ¹³C NMR experiments were performed at low temperature (from −30 to −50 °C), as in the case of [Cp(CO)(PPh₃)Fe(NCCH₃)][NCW(CO)₅] (2a) and [Cp(CO)(Benzyl-NC)Fe(NCCH₃)][NCW(CO)₅] (2b). When the same reaction was carried out in dichloromethane solution, neutral cyanide-bridged dinuclear complexes [Cp(CO)(L)FeNCM(CO)₅] [M=W, L=PPh₃ (5a), CN-Benzyl (5b); M=Cr, L=(PPh₃) (6a), CN-2,6-Me₂C₆H₃ (6c), CO (6g); M=Mo, L=CN-2,6-Me₂C₆H₃ (7c), CO (7g)] were obtained and characterized by infrared and NMR spectroscopy. In all cases, the room temperature ¹³C NMR measurements showed no broadening of cyano pentacarbonyl signals and, relative to tungsten complexes [Cp(CO)(PPh₃)FeNCW(CO)₅] (5a) and [Cp(CO)(CN-Benzyl)FeNCW(CO)₅] (5b), the presence of ¹⁸³W satellites of the ¹³CN resonances (J_CW ∼ 95 Hz) at room temperature confirmed the formation of stable neutral species. The main ¹³C NMR spectroscopic properties of the latter compounds were compared to those of the linkage isomers [Cp(CO)(PPh₃)FeCNW(CO)₅] (8a) and [Cp(CO)(CN-Benzyl)FeCNW(CO)₅] (8b). The characterization of the isomeric couples 5a-8a and 5b-8b was completed by the analyses of their main IR spectroscopic properties. The crystal structures determined for 2a, 5a, 8a and 8b allowed to investigate the geometrical and electronic differences between such complexes. Finally, the study was completed by extended Hückel calculations of the charge distribution among the relevant atoms for complexes 2a, 5a and 8a.     

Preparation and characterization of mono-cyclopentadienylvanadium dihalide bis-phosphine complexes; crystal structure of (η5-C5H5)VCL2(PMe3)2

Mono-cyclopentadienyl complexes CpVX₂(PR₃)₂ and Cp′VX₂ (PR₃)₂ (Cp = η⁵- C₅H₅; Cp′ = η⁵-C₅H₄Me; R = Me, Et; X = Cl, Br) have been prepared by reaction of VX₃(PR₃)₂ with CpM (M = Na, T1, SnBuⁿ3, 1/2 Mg) or Cp′Na. Attempts to prepare analogous complexes with other phosphine ligands, PPh₃, PPh₂ Me, PPhMe₂, Pcy₃, DMPE and DPPE failed. Reduction of CpVCl₂(PEt₃)₂ with zinc or aluminium under CO (1 bar) offers a simple method for the preparation of CpV(CO)₃(PEt₃). The crystal structure of the trimethylphosphine complex CpVCl₂(PMe₃)₂ is reported.     

Synthesis and reaction chemistry of 4-nitrile-substituted NCN-pincer palladium(II) and platinum(II) complexes (NCN = [NC-4-C6H2(CH2NMe2)2-2,6])

Nitrile-functionalized NCN-pincer complexes of type [MBr(NC-4-C₆H₂(CH₂NMe₂)₂-2,6)] (6a, M = Pd; 6b, M = Pt) (NCN = [C₆H₂(CH₂NMe₂)₂-2,6]⁻) are accessible by the reaction of Br-1-NC-4-C₆H₂(CH₂NMe₂)₂-2,6 (2b) with [Pd₂(dba)₃ · CHCl₃] (5a) (dba = dibenzylidene acetone) and [Pt(tol-4)₂(SEt₂)]₂ (5b) (tol = tolyl), respectively. Complex 6b could successfully be converted to the linear coordination polymer {[Pt(NC-4-C₆H₂(CH₂NMe₂)₂-2,6)](ClO₄)}_n (8) upon its reaction with the organometallic heterobimetallic π-tweezer compound {[Ti](μ-σ,π-CCSiMe₃)₂}AgOClO₃ (7) ([Ti] = (η⁵-C₅H₄SiMe₃)₂Ti).The structures of 6a (M = Pd) and 6b (M = Pt) in the solid state are reported. In both complexes the d⁸-configurated transition metal ions palladium(II) and platinum(II) possess a somewhat distorted square-planar coordination sphere. Coordination number 4 at the group-10 metal atoms M is reached by the coordination of two ortho-substituents Me₂NCH₂, the NCN ipso-carbon atom and the bromide ligand. The NC group is para-positioned with respect to M.     

Cp2Ti{[OC(O)C5H4]Cr(CO)2NO]}2 and Cp2Ti{[(OC(O)C5H4]Cr(NO)2X}2 syntheses and spectra of chromium-titanium complexes bridged by carboxylate substituted cyclopentadienyl group

Complete demethylation of Cp₂Ti(CH₃)₂ in dichloromethane with 2 M equivalent of [η⁵-(C₅H₄COOH)]Cr(CO)₂NO (5), [η⁵-(C₅H₄COOH)]Cr(NO)₂X] (X = Cl 6, X = I 7), and [η⁵-(C₅H₄COOH)]W(CO)₃CH₃ (8); gives Cp₂Ti{[OC(O)C₅H₄]Cr(CO)₂NO}₂ (13), Cp₂Ti{[OC(O)C₅H₄]Cr(NO)₂Cl}₂ (14), Cp₂Ti{[OC(O)C₅H₄]Cr(NO)₂I}₂ (15),and Cp₂Ti{[OC(O)C₅H₄]W(CO)₃CH₃}₂ (16), respectively. The chemical shifts of C(2)-C(5) carbon atoms of compounds 13-15 have been assigned using two-dimensional HetCOR NMR spectroscopy. The assigned chemical shifts were compared with the NMR data of their analogues of ferrocene, and the opposite correlation on the assignments was observed for cynichrodenoyl moieties.     

C-H activation of benzene with CpRu(CO)2CH3

Irradiation of Cp^∗Ru(CO)₂CH₃ (1) in C₆D₆ at room temperature yields Cp^∗Ru(CO)₂C₆D₅ and CH₃D (where Cp^∗ = n⁵-C₅Me₅). Cp^∗Ru(CO)₂CD₃ (2) has also been prepared and similar irradiation in C₆H₆ yields Cp^∗Ru(CO)₂C₆H₅ (3) and CD₃H. This latter reaction confirms that it is the methyl group bonded to ruthenium that is involved in the C-H activation process and not the methyl groups on the Cp^∗ ligand system. The compound Cp^∗Ru(CO)₂C₆H₅ (3) has been prepared for the first time in good yield by the reaction of Cp^∗Ru(CO)₂Br with NaBPh₄. X-ray crystal structures of both Cp^∗Ru(CO)₂CH₃ (1) and Cp^∗Ru(CO)₂C₆H₅ (3) have been determined and the results are reported and discussed.     

Structural and energetic aspects of hydrogen bonding and proton transfer to ReH2(CO)(NO)(PR3)2 and ReHCl(CO)(NO)(PMe3)2 by IR and X-ray studies

The interaction of rhenium hydrides ReHX(CO)(NO)(PR₃)₂ 1 (X=H, R=Me (a), Et (b), iPr (c); X=Cl, R=Me (d)) with a series of proton donors (indole, phenols, fluorinated alcohols, trifluoroacetic acid) was studied by variable temperature IR spectroscopy. The conditions governing the hydrogen bonding ReHHX in solution and in the solid state (IR, X-ray) were elucidated. Spectroscopic and thermodynamic characteristics (−ΔH=2.3–6.1 kcal mol⁻¹) of these hydrogen bonded complexes were obtained. IR spectral evidence that hydrogen bonding with hydride atom precedes proton transfer and the dihydrogen complex formation was found. Hydrogen bonded complex of ReH₂(CO)(NO)(PMe₃)₂ with indole (2a–indole) and organyloxy-complex ReH(OC₆H₄NO₂)(CO)(NO)(PMe₃)₂ (5a) were characterized by single-crystal X-ray diffraction. A short NHHRe (1.79(5) Å) distance was found in the 2a–indole complex, where the indole molecule lies in the plane of the Re(NO)(CO) fragment (with dihedral angle between the planes 0.01°).     

Synthesis, properties and structures of the two “electron rich” cobalt-sulphur clusters [Co6(μ3-S)8(PEt3)6]

The reaction of hydrogen sulphide with [Co(H₂O)₆](BF₄)₂ and triethylphosphine in the presence of sodium tetraphenylborate or tetrabutylammonium hexafluorophosphate gave the paramagnetic clusters [Co₆(μ₃-S)₈(PEt₃)₆](Y) (Y = BPh₄, (1), PF₆, (2)). These compounds can be easily reduced by sodium napthalenide to the diamagnetic species [Co₆(μ₃-S)₈(PEt₃)₆] · 2C₄H₈O (3). The molecular structures of 1 and 3 have been established by single-crystal X-ray diffraction methods. Crystal data: (1) space group P , a = 19.481(9), b = 15.562(7), c = 12.390(b) Å, α = 92.70(8), β = 94.50(7), γ = 94.10(9)°, Z = 2, (3) space group R , a = 11.780(6) Å, α = 92.50(7)°, Z = 1. Both structures were solved by the heavy atom method and refined by full-matrix least-squares techniques to the conventional R factors values of 0.050 for 1 and 0.044 for 3 on the basis of 4251 and 1918 observed reflections, respectively. The two clusters [Co₆(μ₃-S)₈)(PEt₃)₆]^1+,0 are isostructural, the inner core consisting of an octahedron of cobalt atoms with all the faces symmetrically capped by triply bridging sulphur atoms. Each metal centre is additionally linked to a triethylphosphine group so that each cobalt atom is co-ordinated by four sulphur atoms and one phosphorus in a distorted square pyramidal environment. The addition of one electron whilst leaving unchanged the geometry of the inner framework, induces small changes in the structural parameters, the average Co---Co and Co---P distances being 2.794 (3) and 2.162 (2) Å for 1 and 2.817 (3) and 2.138 (2) Å for 3 respectively. Electrochemistry in non-aqueous solvents shows the electron-transfer sequence

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The tricationic species is stable only in the short time of cyclic voltammetric tests.     

Reactivity of 2,3-bis(2-pyridyl)pyrazine with [Re2(CO)8(CH3CN)2]: Molecular structures of [Re2(CO)8(C14H10N4)] and [Re2(CO)8(C14H10N4)Re2(CO)8]

The reaction of the labile compound [Re₂(CO)₈(CH₃CN)₂] with 2,3-bis(2-pyridyl)pyrazine in dichloromethane solution at reflux temperature afforded the structural dirhenium isomers [Re₂(CO)₈(C₁₄H₁₀N₄)] (1 and 2), and the complex [Re₂(CO)₈(C₁₄H₁₀N₄)Re₂(CO)₈] (3). In 1, the ligand is σ,σ′-N,N′-coordinated to a Re(CO)₃ fragment through pyridine and pyrazine to form a five-membered chelate ring. A seven-membered ring is obtained for isomer 2 by N-coordination of the 2-pyridyl groups while the pyrazine ring remains uncoordinated. For 2, isomers 2a and 2b are found in a dynamic equilibrium ratio [2a]/[2b]  =  7 in solution, detected by ¹H NMR (−50 °C, CD₃COCD₃), coalescence being observed above room temperature. The ligand in 3 behaves as an 8e-donor bridge bonding two Re(CO)₃ fragments through two (σ,σ′-N,N′) interactions. When the reaction was carried out in refluxing tetrahydrofuran, complex [Re₂(CO)₆(C₁₄H₁₀N₄)₂] (4) was obtained in addition to compounds 1-3. The dinuclear rhenium derivative 4 contains two units of the organic ligand σ,σ′-N,N′-coordinated in a chelate form to each rhenium core. The X-ray crystal structures for 1 and 3 are reported.     

Synthesis and characterisation of HRuRh3(CO)12. Crystal structures of HRuRh3(CO)12, HRuRh3(CO)10(PPh3)2 and HRuCo3(CO)10(PPh3)2

A new ruthenium-rhodium mixed-metal cluster HRuRh₃(CO)₁₂ and its derivatives HRuRh₃(CO)₁₀(PPh₃)₂ and HRuCo₃(CO)₁₀(PPh₃)₂ have been synthesized and characterized. The following crystal and molecular structures are reported: HRuRh₃(CO)₁₂: monoclinic, space group P2₁/c, a 9.230(4), b 11.790(5), c 17.124(9) Å, β 91.29(4)°, Z = 4; HRuRh₃(CO)₁₀(PPh₃)₂·C₆H₁₄: triclinic, space group P$\text{1}$, a 11.777(2), b 14.079(2), c 17.010(2) Å, α 86.99(1), β 76.91(1), γ 72.49(1)°, Z = 2; HRuCo₃(CO)₁₀(PPh₃)₂·CH₂Cl₂: triclinic, space group P$\text{1}$, a 11.577(7), b 13.729(7), c 16.777(10) Å, α 81.39(4), β 77.84(5), γ 65.56°, Z = 2. The reaction between Rh(CO)₄^? and (Ru(CO)₃Cl₂)₂ tetrahydrofuran followed by acid treatment yields HRuRh₃(CO)₁₂ in high yield. Its structural analysis was complicated by a 80–20% packing disorder. More detailed structural data were obtained from the fully ordered structure of HRuRh₃(CO)₁₀(PPh₃)₂, which is closely related to HRuCo₃(CO)₁₀(PPh₃)₂ and HFeCo₃(CO)₁₀(PPh₃)₂. The phosphines are axially coordinated.     

Studies of lambert's reaction: The formation of [Mn2(CO)8(μ-AsR2)2] complexes from tertiary arsines and [Mn2(CO)10] at high temperatures

Although very bulky ligands e.g.(o-MeC₆H₄)₃E or (μ-C₁₀H₇)₃E (E = P or As) are inert, the normal photochemical or thermal reaction of tertiary phosphines or arsines, L, with [Mn₂(CO)₁₀] is CO substitution with the formation of [Mn₂(CO)₈(L)₂] derivatives (I). At elevated temperatures some triarylarsines, R₃As, undergo Lambert's reaction with ligand fragmentation to give [Mn₂(CO)₈(μ-AsR₂)₂] complexes (II) (R = Ph, p-MeOC₆H₄, p-FC₆H₄, or p-CIC₆H₄) even though, in the absence of [Mn₂(CO)₁₀] R₃As are stable under the same conditions. Exceptional behaviour is exhibited by (p-Me₂NC₆H₄)_3- As which forms a product of type I; by some HN(C₆H₄)₂AsR which give a product of type II as a result of loss of the non-aryl groups R = PhCH₂, cyclo-C₆H₁₁, or MeO; and by Ph(α-C₁₀H₇₂P which is the only phosphine to form a product of type II, albeit in trace amounts only. The thermal decomposition of a n-butanol solution of [Mn₂(CO)₈(AsPh₃)₂] in a sealed tube gives C₆H₆ and [Mn₂(CO)₈(α-AsPh₂)₂], whilst in an open system in the presence of various tertiary phosphines, L, [Mn(H)(CO)₃(L)₂] are obtained. It is suggested that Lambert's reaction is a thermal fragmentation of [Mn(CO)₄(AsR₃]^* radicals, the first to be recognised. They lose the radical R^* which abstracts hydrogen from the solvent. The resulting [Mn(CO)₄(AsR₂)] moiety dimerises to [Mn₂(CO)_8-(α-AsR₂)₂]. the reaction is facilitated by the stability of the departing radical (e.g. PhCH₂ or MeO) and, as the crowding about As is relieved, by its size (e.g. Ph, cyclo-C₆H₁₁, o-MeC₆H₄, or α-C₁₀H₇). In general, phosphine-substituted radicals [Mn(CO)₄(PR)₃]^* do not undergo this decomposition, probably because the PC bonds are much stronger than AsC.     

Reaction studies on some functionalized alkyl transition metal compounds and the crystal structure of [Cp(CO)3W{(CH2)3NO2}]

The reactions of the halogenoalkyl compounds [Cp(CO)₃W{(CH₂)_nX}] (Cp = η⁵-C₅H₅; n = 3-5; X = Br, I) and [Cp(CO)₂(PPhMe₂)Mo{(CH₂)₃Br}] with the nucleophiles Z = CN⁻ and gave compounds of the type [Cp(CO)₃W{(CH₂)_nZ}] for the tungsten compounds, whilst cyclic carbene compounds were obtained from the reactions of the molybdenum compound. The reactions of [Cp(CO)₃W{(CH₂)_nBr}] (n = 3, 4) and [Cp(CO)₂(PPhMe₂)Mo{(CH₂)₃Br}] with gave [Cp(CO)₃W{(CH₂)_nONO₂}] and [Cp(CO)₂(PPhMe₂)Mo{(CH₂)₃ONO₂}], respectively. The reaction of [Cp(CO)₃W{(CH₂)_nBr}] with AgNO₂ gave [Cp(CO)₃W{(CH₂)_nNO₂}]. In the solid state the complex [Cp(CO)₃W{(CH₂)₃NO₂}] crystallizes in a distorted square pyramidal geometry. In this molecule the nitropropyl chain deviates from the ideal, all-trans geometry as a result of short, non-hydrogen intermolecular N-O?O-N contacts. The reactions of the heterobimetallic compounds [Cp(CO)₃W{(CH₂)₃}ML_y] {ML_y = Mo(CO)₃Cp, Mo(CO)₃Cp^∗ and Mo(CO)₂(PMe₃)Cp; Cp^∗ = η⁵-C₅(CH₃)₅} with PPh₃ and CO were found to be totally metalloselective, with the ligand always attacking the metal site predicted by the reactions of the corresponding monometallic analogues above with nucleophiles. Thus the compounds [Cp(CO)₃W{(CH₂)₃}C(O)ML_z] {ML_z = Mo(CO)₂YCp, Mo(CO)₂YCp^∗ and Mo(CO)Y(PMe₃)Cp; Y = PPh₃ or CO} were obtained. Similarly, the reaction of [Cp(CO)₂Fe{(CH₂)₃}Mo(CO)₂(PMe₃)Cp] with CO gave only [Cp(CO)₂Fe{(CH₂)₃C(O)}Mo(CO)₂(PMe₃)Cp]. Hydrolysis of the bimetallic compound, [Cp(CO)₃W(CH₂)₃C(O)Mo(CO)(PPh₃)(PMe₃)Cp], gave the carboxypropyl compound [Cp(CO)₃W{(CH₂)₃COOH}]. Thermolysis of the compound [Cp(CO)₂Fe(CH₂)₃Mo(CO)₃(PMe₃)Cp] gave cyclopropane and propene, indicating that β-elimination and reductive processes had taken place.     

Radikalkomplexe vom typ Cp(CO)2MnXR. (X = S,Se)

CpMn(CO)₂ER (E = S, Se) compounds [1] belong to the rare radical derivatives of the CpMn(CO)₂ fragment. We describe herein the syntheses, electrochemistry, and organometallic reactions of CpMn(CO)₂SR ¹ (1a: R = t-C₄H₉, 1b: R = 2-adamantyl) and CpM(CO)₂SePh (2).     

Syntheses and structural studies on two cycloruthenapentadienyl complexes: [(CO)3RuC4(CH2OH)4]Ru(CO)3·H2O and [(CO)3RuC4(CH2CH2OH)2(C2H5)2]Ru(CO)3

Syntheses and single-crystal X-ray diffraction studies have been completed on two cycloruthenapentadienyl (CO)₆Ru₂L₂ derivatives, with L = CH₂OHC = CCH₂OH and C₂H₅C=CCH₂CH₂OH respectively. Crystal data are as follows: for [(CO)₃RuC₄(CH₂OH)₄]Ru(CO)₃·H₂O, P2₁/c, a 13.72(1), b 9.501(4), c 14.86(1) Å, β 101.10(6)°, R_w = 0.052 for 1911 reflections; for [(CO)₃RuC₄(CH₂CH₂OH)₂(C₂H₅)₂]Ru(CO)₃, P2₁/c, a 9.191(3), b 16.732(4), c 14.903(3) Å, β 113.61(4)°, R_w = 0.042 for 2865 reflections. Both compounds are built up from binuclear units, each unit being regarded as a Ru(CO)₃ fragment π-bonded to a cycloruthenapentadienyl ring. The molecular parameters are compared with those of known cyclometallapentadienyl complexes of transition metals. The presence of a semi-bridging CO group is discussed.     

Organogold(III) metallacyclic chemistry. Part 4. Synthesis, characterisation, and biological activity of gold(III)-thiosalicylate and -salicylate complexes

The silver(I) oxide mediated reactions of the gold(III) dichloride complex [{C₆H₃(CH₂

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uCl₂] 2a with thiosalicylic or salicylic acid gives the respective complexes [{C₆H₃(CH₂

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)-2}] 3a (X=S) or 6b (X=O), containing chelating thiosalicylate or salicylate dianion ligands. X-ray studies show that for the thiosalicylate system, the thiosalicylate sulfur atom is trans to the N,N-dimethylamino group, whereas in the structure of the salicylate complex, it is the carboxylate group that is trans to NMe₂. Both complexes show puckered metallacycles in the solid state. Electrospray mass spectrometry (ESMS) shows strong [M+H]⁺ and [2M+H]⁺ ions for both the gold-thiosalicylate and -salicylate complexes, and these ions possess a high stability towards cone voltage-induced fragmentation. ESMS was also used to identify a minor impurity, the bis(cyclo-aurated) cationic complex [A

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Me₂)-2-(OMe)-5}2]⁺ in the starting dihalide complex 2a and in the product 3a. This complex can be formed by reaction of Me₄N[AuCl₄] with 2 equivalents of the organomercury precursor [Hg{C₆H₃(CH₂NMe₂)-2-(OMe)-5}Cl]. The biological (antitumour, antimicrobial and antiviral) activities are also reported, and these reveal the complexes have moderate to high anti-tumour, antibacterial and antifungal activity.