Cationic di-iron complexes {[η-C5Fe(CO)2]2[μ-(CnH2n1)]}+

The reactions of the complexes [CpFe(CO)₂]₂[μ-(CH₂)_n with Ph₃CPF₆ yield cationic di-iron complexes of the type {[CpFe(C     

35Cl NQR in N3P3Cl4Ph2 and N3P3Cl4(NMe2)2

³⁵Cl NQR has been investigated in two cyclotriphosphazene derivatives N₃P₃Cl₄Ph₂ and N₃P₃Cl₄(NMe₂)₂. The observed frequencies are assigned to the various chlorines and the temperature variation of the NQR frequencies studied in the range from 77 K to 300 K. The results are analysed using the Bayer-Kushida-Brown approach. Torsional (librational) frequencies are found to fall in the range 10–25 cm^?1 and are found to be only slightly temperature dependent.     

Synthesis and characterisation of some salts of the ions [Rh(Oxalato)2(Rpy)2]−

Salts of three bisoxalato bis(pyridine) species, trans-[Rh(ox)₂(py)₂]^?, trans-[Rh(ox)₂(3-Mepy)₂]^? and trans-[Rh(ox)₂(4-Mepy)₂]^? have been isolated from the substitution of N-heterocycles into trisoxalatorhodate(III) and characterised on the basis of ¹H NMR and ¹³C NMR spectra, which are similar to that of the trans-[Co(oxalato)₂ (R-py)₂]^? complex.     

Mononuclear,three-coordinate metal thiolates: Preparation and crystal structures of [NBun4][Hg(SPh)3] and [NPrn4] [Pb(SPh)3]

Dissolution of HgO or PbO in methanolic solutions of NaSPh yields homogeneous solutions from which highly crystalline [NBuⁿ₄][Hg(SPh)₃] (1) or [NPrⁿ⁴][PB(SPh)₃] (2) can be isolated on addition of appropriate quaternary ammonium salts. 1 crystallizes in monoclinic space group P2₁/a with a = 20.663(7), b = 16.812(6), c = 9.757(3) Å, β = 95.52(2)° and Z = 4. The anion consists of a rare example of trigonal planar coordinated Hg; there are no weaker, intermolecular Hg ... S axial interactions. 2 crystallizes in triclinic space group Pl? with a = 12.689(7), b = 11.255(6), c = 12.046(7) Å, α = 107.93(3), β = 109.64(3), γ = 86.01(3)°, and Z = 2. The anion consists of a trigonal pyramidal coordinated PbS₃ unit. The structures were solved using data collected at approx. ? 160°C and refined to conventional R values of 5.7 and 4.6%, respectively for 1 and 2.     

31P and 195Pt NMR spectra of [Pt(PPh32(μ-η2-C2H4−nXn)] (n = 0 … 4; X = CN,COOMe)

³¹P and ¹⁹⁵Pt NMR measurements on compounds of the type [Pt(PPh₃)₂ (μ-η²-C₂H_4?nX_n)] (n = 0…4; X = CN, COOMe) are reported and discussed.     

Photochemistry of aqueous [W(CN)8]4−

Aqueous [W(CN)₈]^4? undergoes photoaquation when irradiated at ～ 365 nm with pH independent quantum yield. The yield for aquoheptacyanotungstate (IV) ion production is 0.8 at 0.5°C. If added alkali is present a wide variety of products [W(CN)₇(OH)]^4?, [WO₂(CN)₄]^4?, [WO(OH)(CN)₄]^3? [W(OH)₂(CN)₄]^2? are formed.     

Vibrational and luminescence spectra of a new binuclear uranyl complex [(C2H5)4N]2[UO2F(NO3)2]2

The preparation, vibrational and luminescence spectra of the title compound are described. The complex has bidentate nitrate groups and bridging fluoride ions. The spectra are assigned in detail and interpreted as showing couplings between the uranyl antisymmetric stretching modes and between the nitrate modes within the dimer, the coupling energy being 17 cm^? in the former case. There is no clear evidence for electronic coupling involving the uranyl groups.     

Preparation of mixed isopropyl/trimethylsilyl derivatives of boric acid, (Me3SiO)nB(OiPr)3-n(n = 1–3), and their GC-M

Boric acid was trimethylsilylated with Me₃SiCl/(Me₃Si)₂O in the presence of 2-propanol. The resulting mixture was analysed by using a combi     

Pressure dependence of 35Cl NQR in hexachloro- (N3P3Cl6) and octachloro- (N4P4Cl8) cyclophosphazenes

High pressure studies of ³⁵Cl NQR in the hexachlorocyclophosphazene N₃P₃Cl₆ and in the K- and T-forms of octachlorocyclophospha     

The preparation and synthetic value of fac-[M(CO)3(NCR)3]+ cations (M  Mn or Re; R  Et,Pr OR PhCH2)

Treatment of MBr(CO)₅ (M = Mn or Re) with AgClO₄ and an organonitrile in a suitable solvents affords the complexes fac-[M(CO)₃(NCR)₃][ClO₄], (R = Et, Pr or PhCH₂). The use of these complexes as synthetic precursors has been illustrated by the preparation of fac-[M(CO)₃L₃][ClO₄], (M = Mn, L = NH₃ or L₃ = dien; M = Re, L₃ = triphos). Pure fac-[Re(CO)₃(NH₃)₃][ClO₄] could not be prepared using this nitrile displacement route, but may be isolated, as the PF₆^? salt, from the reaction of [Re(CO)₃(toluene)][PF₆] and ammonia in chloroform.     

Synthesis and molecular structure of [Au3Ru4(μ3-H)(CO)12(PPh3)3]

The title compound can be prepared in good yield by heating either [Ru₄(μ-H)₄(CO)₁₂] or [Au₂Ru₄(μ₃-H)₂(CO)₁₂(PPh₃)₂] with [AuMe(PPh₃)] in toluene. The related compound [Au₃Ru₄(μ₃-H)(μ-dppm)(CO)₁₂(PPh₃)] has also been prepared. Both trigoldtetraruthenium clusters undergo dynamic behaviour in solution, involving intramolecular rearrangement of the metal core, as revealed by variable temperature NMR studies. The crystal structure of [Au₃Ru₄(μ₃-H)(CO)₁₂(PPh₃)₃] has been established by an X-ray diffraction study. The metal atom core comprises a trigonal bipyramidal AuRu₄ unit with two AuRu₂ faces capped by gold atoms.     

Some transesterification reactions of [Ir(CO2Me)(CO)2(PPh3)2]

The iridium(I) complex [Ir(CO₂Me)(CO)₂(PPh₃)₂] undergoes a transesterification reaction with the alcohols CH₂C(R)CH₂OH (R = H, Me), MeCCCH₂CH₂OH, and HOCH₂CH₂OH to afford the complexes

[Ir(CO₂CH₂CH₂CMe)(CO)₂(PPh₃)₂] and [Ir(CO₂CH₂CH₂OH)(CO)₂(PPh₃)₂], respectively. In contrast the acetylenic alcohol HCCCH₂CH₂OH gives [Ir(CCCH₂CH₂OH)(CO)PPh₃)₂]. Some reactions of the new complexes are described.     

Mixed-valence electron delocalized thiocyanato bridged ruthenium dinuclear complex [{Ru(NH3)5}2SCN]4+

The thiocyanato bridged mixed-valence ruthenium dinuclear species [{Ru(NH₃)₅}2SCN]⁴⁺ has been prepared and characterized. A solvent independent, low intensity intervalence transfer band was observed in the near IR absorption spectrum suggesting a delocalized limit in the [Ru(II)-SCN-Ru(III)] unit.     

Further studies of phosphine adducts of niobium(IV) and tantalum(IV) chlorides: New seven- and eight-coordinate compounds with trimethylphosphine: NbCl4(PMe3)3 and Ta2Cl8(PMe3)4

The reaction of NbCl₄(THF)₂ with an excess of PMe₃ in toluene solution afforded a 70% isolated yield of green NbCl₄(PMe₃)₃. When a slurry of TaCl₅ in toluene containing a slight excess of PMe₃ was reduced with sodium amalgam overnight, a 60% yield of orange to red (depending on crystal size) Ta₂Cl₈(PMe₃)₄ was obtained. Both compounds have been fully characterized by X-ray crystallography. NbCl₄(PMe₃)₃ forms monoclinic crystals (P2₁/c) with unit cell dimensions a = 15.061(3) Å, b = 11.677(4) Å, c = 11.583(4) Å, β = 91.71(3)°, V = 2036(2) ų, and Z = 4. It is isomorphous with its TaCl₄(PMe₃)₃ homolog, and the bond lengths and angles are very similar. Ta₂Cl₈(PMe₃)₄ forms cubic crystals (Im3) with a = 16.377(2), V = 4392(2) ų and Z = 6. It is thus isomorphous with its niobium homolog, and the internal dimensions are quite comparable. The Ta-Ta distance is 2.830(1) Å, consistent with the existence of a single bond.     

New triosmium metal clusters derived from the reactions between [Os3(CO)10(NCMe)2] and amides

Triosmium clusters of the type [Os₃(CO)₁₀(μ-H)(NHCOR)] (1; R = H, Me, Ph, Et or Pr) are formed in high yields form the reaction of [Os₃(CO)₁₀(NCMe)₂] (2) with amides. The nature of the products formed from thermolysis of 1 depend on the group, R.     

Synthesis and structural characteristics of fac-ReCl3[P(OEt)3]3 a route to the phosphite complexes

Reaction of the oxo-complex ReOCl₃(PPh₃)₂ with an excess of triethylphosphite yields a deoxygenated rhenium phosphite complex fac-ReC1₃[P(OEt)₃]₃; its structure was confirmed by ¹H NMR and IR spectroscopy.     

Synthesis and spectroscopic characterization of heterobimetallic (α-alkynyl)iron-cobalt hexacarbonyl complexes, μ-(1-σ, 2-3, η2-R2C-CCR′)][(CO)3Fe-Co(CO)3] and [μ-(1-σ, 2-3, η2-H2C-CCCH2OH)] [(CO)3Fe-Co(CO)2(PPh3)]

The title compounds have been prepared from reactions of Co₂(CO)₆(μ-HOR₂CC₂R′) or Co₂(CO)₆(μ-HOR₂CC₂CR₂OH) complexes with Fe(CO)₅ in acetone. In the latter set of reactions the homobimetallic butatriene compounds, Fe₂(CO)₆-(μ-R₂CCCCR₂), are also obtained. The striking feature of these reactions is the ability of Fe(CO)₅ to dehydroxylate the organic moiety and to replace a Co(CO)₃ unit forming mixed iron-cobalt derivatives. A direct interaction between the iron and the carbon atom, originally bearing the lost -OH group, is evident from the bulk of the spectroscopic data; thus the organic chain acts as an overall 5 electron donor, according to the E.A.N. formalism. The heterobimetallic compounds have been characterized by elemental analysis, mass spectrometry, IR spectroscopy and NMR studies. For the phosphine derivative FeCo(CO)₅(PPh₃)(H₂CC₂OH) a crudely refined X-ray analysis has been performed.     

The direct electrochemical synthesis and crystal structure of salts of [M4(SC6H5)10]2− anions (M = Zn,Cd)

The salts [(C₂H₅)₃NH]₂[M₄(SC₆H₅)₁₀] (M = Zn, Cd) can be prepared by the electrochemical oxidation of the metal in an acetonitrile solution of triethylamine and benzenethiol. An X-ray crystal structure determination shows that the anion consists of a tetrahedron of metal atoms, each carrying a terminal -SC₆H₅ ligand, and connected to the three other metal atoms by bridging > SC₆H₅ groups. The results are compared with those for similar compounds reported in the literature.     

The influence of the steric properties of the ligands PR2Ph and L on the formation and properties of the complexes Mo(η6-PhPR2)(L)(PPh2CH2CH2PPh2), R = Et,L = PPhEt2 and R = Ph,L = PPh3, PR′3, CO,CNR, N2, H2

The reduction of MoCl₄(DPPE) (DPPE = PPh₂CH₂CH₂PPh₂) with Mg or Na/Hg in the presence of 2 PPhR₂ under Ar results in the formation of the new complexes Mo(η⁶-PhPR₂)(PPhR₂)(DPPE) when R is Ph (Ia) or Et(II). No η⁶-PhPR₂ complex is obtained when R is Me because this small ligand forms strong MoP σ-bonds; nor is one obtained for R = Cy because of too much steric crowding. The limits for η⁶-complexation can be quantified in terms of cone angle sums.Complex Ia is very similar to Mo(η⁶-PhPMePh)(PMePh₂)₃ (IIIa) in that both react at similar rates with a variety of small ligands L = PMePh₂, PMe₂Ph, PMe₃, P(OMe)₃, N₂, CO, CNBu^t and H₂ via dissociation of a labile σ-bonded ligand. Several other less crowded η⁶-arylphosphinemolybdenum complexes including II do not have labile ligands at 25°C. The new complexes Mo(η⁶-PhPPh₂)(L)(DPPE) have been characterized by ³¹P and ¹H NMR, IR and gas uptake measurements, Ia has a higher affinity for H₂ than IIIa possibly because Mo(η⁶-PhPPh₂)(H)₂(DPPE) adopts a non-fluxional trans-configuration. The ³¹P chemical shift of the σ-bonded ligand in 8 derivatives of Ia and 12 of IIIa correlate with the sum of the cone angles of the three σ-bonded ligands in each complex.     

Interaction of the E(D) state of Co with a jahn-teller active mode in [N(CH3)4]2CoCl4

The transition ⁴A₂ → ²E of Co²⁺ has been investigated in [N(CH₃)₄]₂CoCl₄ using optical absorption and magnetic circular dichroism. Three groups of lines with 274 cm⁻¹ progressions were observed. The structure of the spectra indicates a J-T interaction in the ²E state with strong depression of the frequency of the J-T active mode. The ground-state splitting is 7.2 cm⁻¹.