Mn CO Research Articles

Fe–Zn manganite spinels and their carbonate precursors: preparation, characterization and catalytic activity

Iron–zinc manganites at different Fe content [x=Fe/(Fe+Zn)=0, 0.01, 0.05, 0.10] were prepared by thermal decomposition of carbonate precursors obtained by coprecipitation at constant pH. Precursors were characterized by diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA-DTA) and magnetic susceptibility measurements. All samples are made by a single rhodochrosite-like phase, FexZnyMn(1−x−y)CO3, in which besides Zn2+ and Mn2+, only 5% of the total iron was Fe2+, the remaining 95% surprisingly being Fe3+ ions. The carbonate monophasic precursors were decomposed at 723 and 973K in air and solid solutions of iron in the zinc manganite spinel-like phase were obtained at both temperatures. Zinc manganite, ZnMn2O4, is a ‘normal’ spinel in which the Zn2+ ions occupy the tetrahedral sites and Mn3+ ions the octahedral sites of the crystal lattice. When iron is loaded, it is present as Fe3+ ions in the octahedral sites of the spinel together with Mn3+ ions. The catalyst reducibility in H2 was studied by temperature-programmed reduction (TPR). The iron-containing catalysts resulted to be slightly more resistant towards reduction than pure ZnMn2O4, suggesting that Fe3+ ions play a stabilizing effect on the spinel structure. Results of a Mössbauer investigation on the iron chemical state and its coordination symmetry are extensively reported. Some preliminary results of the catalytic behaviour for the reduction of NO by hydrocarbons are presented.

Catalytic activity of copper-zinc manganites for the reduction of NO and N2O by hydrocarbons

The catalytic behaviour of copper-zinc manganites with general formula CuxZn1−xMn2O4 (x=0, 0.01, 0.05, 0.10) was investigated for the reduction of NO by hydrocarbons. Also the N2O decomposition and its reduction by propane and propene were tested on representative samples. The catalysts were obtained by thermal decomposition at 973K of carbonate precursors. Regardless the composition, all the precursors are monophasic and made by a rhodochrosite-like phase, CuxZnyMn(1−x−y)CO3, in which Cu2+ and Zn2+ ions entered in solid solution. The metal dispersion in the precursors is preserved by the final catalysts that, in spite of the presence of copper, are monophasic and made by a CuxZn1−xMn2O4 spinel-like phase. The reduction of NO was studied by using CH4, C3H8 and C3H6 as reducing agents and the last two hydrocarbons were used for testing the N2O reduction. Propene is the most effective hydrocarbon followed by propane whereas methane is efficient only at higher reaction temperatures. Pure zinc manganite is an active catalyst but the presence of copper in the spinel enhanced the catalytic activity of NO reduction by propane and slightly improved that of N2O reduction. Moreover, regardless the presence of copper, a high conversion (70–100%) of NO to N2 was attained at 873K and the selectivity to N2 and CO2 was close to 1. The catalysts are stable in the CH4 and C3H8 containing streams within the whole range of temperature explored. By contrast, when C3H6 is used as reductant the spinel structure is preserved only below 773K because at higher temperatures it collapses by reduction of Mn3+ to Mn2+ ions forming a mixture of ZnO and MnO oxides. At this stage the catalysts are still active and an attempt to explain this evidence is made.

Ultrafast non-adiabatic laser-induced photodissociation dynamics of CpMn(CO)3. An ab initio quantum chemical and dynamical study

The ultrafast laser driven dynamics of CpMn(CO)3, so-called cymantrene, have been investigated by wavepacket propagations on adiabatic coupled CASSCF/MR-CCI potential energy curves calculated for the electronic ground and low-lying metal-centered (MC) excited 1A′ and 1A″ states as a function of one Mn–CO bond elongation. The main features of the absorption spectrum as well as the electronic states populations are investigated by the time-dependent approach including numerical non-adiabatic couplings. The photo-induced simulations use selected laser pulse parameters close to the experimental ones (Daniel et al., Chem. Phys., 2001, 267, 247), where the frequencies correspond to the four main resonant Franck-Condon transitions which can prepare either the parent neutral molecule [CpMn(CO)3]* or the first photofragment [CpMn(CO)2]*.

Synthesis, structure, and magnetic properties of [MnIII(salpn)NCS]n, a helical polymer, and the dimer [MnIII(salpn)NCS]2. Weak ferromagnetism in [MnIII(salpn)NCS]n related to the strong magnetic anisotropy in Jahn-Teller MnIII (salpnH2 = N,N'-bis(salicylidene)-1,3-diaminopropane).

Dimeric [Mn(salpn)NCS](2)(1) and polymeric [Mn(salpn)NCS](n)(2) are formed by the reaction of Mn(CH(3)CO(2))(2).4H(2)O, the schiff base, and thiocyanate. The formation of the two polymorphic forms is solvent and temperature dependent. 1: orthorhombic, space group Pbca, with a = 12.573(2) A, b = 13.970(7) A, c = 18.891(9) A, and Z = 8. 2: orthorhombic, space group Pna2(1), with a = 12.5277(14) A, b = 11.576(2) A, c = 11.513(2) A, and Z = 4. The dimers in 1 are held together by weak noncovalent S...pi (phenyl) interactions leading to a chain along the a-axis. Each monomeric unit of the polymer in 2 is related to its adjacent ones by a 2-fold screw axis leading to a helix along the c-axis. The exchange coupling is nondetectable in the dimer. The magnetic susceptibility of the helical chain fits a classical chain law with J = -3.2 cm(-1) and shows a weak ferromagnetic ordering below 7 K due to spin canting effects.

Electron Impact Ionization of Dicyclopentadienyl-Manganese and Cyclopentadienyl-Manganese-Tricarbonyl Compared with Dimanganese-Decacarbonyl: Appearance Energies, Bond Energies and Enthalpies of Formation

Electron impact (EI) ionization mass spectra, metastable-ion decays and appearance energies are reported for the title compounds. Gas-phase formation enthalpies (Δ Hf) and bond energies (as dissociation energies) are derived from these data. Obtained Δ Hf values for the parent compounds are (–15.65 ± 0.2) eV for Mn2(CO)10, (2.85 ± 0.3) eV for Cp2Mn (Cp = C5H5 = cyclopentadienyl ligand) and (–3.91 ± 0.3) eV for CpMn(CO)3. The mean (Mn–CO) bond energy is 0.97 eV for Mn2(CO)10. In cations, the mean (Mn–CO)+ bond energy ranges from 0.75 to 0.80 eV for Mn2(CO)10 and CpMn(CO)3, respectively. In Cp2Mn+ the dissociation energies are 2.14 eV for the first Cp ligand and 3.21 eV for the second. In the neutral Cp2Mn, 2.12 eV is needed for the detachment of a first Cp ligand and 3.00 eV for the second. The results for the second ligand are valid for the elimination of Cp from CpMn(CO)3 as well.

Preparation, characterization and catalytic activity of Co–Zn-based manganites obtained from carbonate precursors

Cobalt–zinc manganites at rather low Co content (x=Co/(Co+Zn)=0, 0.01, 0.05, 0.10) were prepared by thermal decomposition of carbonate precursors obtained by coprecipitation at constant pH. Precursors were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA-DTA) and magnetic susceptibility measurements. For all samples, a single rhodochrosite-like phase, CoxZnyMn(1−x−y)CO3, was formed, as detected by XRD. Magnetic analysis confirmed that cobalt and manganese were present as Co2+ and Mn2+ in the rhodochrosite crystal lattice. The carbonate monophasic precursors were decomposed at 723 and 973K in air and Co–Zn–Mn based spinel-like solid solutions were obtained at both temperatures. The DRS and magnetic susceptibility data suggested that after calcination cobalt was mainly present as Co3+ ions in the octahedral sites of the spinel together with Mn3+ ions. The catalyst reducibility in H2 was studied by temperature-programmed reduction (TPR). The cobalt containing catalysts reduced almost as the pure ZnMn2O4 suggesting that cobalt does not show a detectable influence on the spinel reducibility. Preliminary results of the catalytic activity for the reduction of NO by hydrocarbons in absence of oxygen are presented.

Decomposition of cyclopentadienyltricarbonylmanganese in highly vibrational excited states

Infrared multiple-photon decompositions (IRMPD) of cyclopentadienyltricarbonylmanganese and its methyl derivative ( η 5-C 5H 4R)Mn(CO) 3 (R=H, CH 3) at 1045.02 cm −1 have been studied using a transversely excited atmospheric (TEA) CO 2 laser and compared with the UV photolysis and thermolysis. The main volatile products of the IRMPD at high laser fluences (200–400 J cm −2) are CO and C 5H 5R both in the absence and presence of PF 3. On the other hand, ( η 5-C 5H 4R)Mn(CO) 2(PF 3) is obtained in the UV photolysis and thermolysis of ( η 5-C 5H 4R)Mn(CO) 3 in the presence of PF 3. Therefore, the initial process in the IRMPD is found to be the dissociation of the Mncyclopentadienyl bond in contrast to that of the MnCO bond in the UV photolysis and thermolysis. The dissociation energy of the Mncyclopentadienyl bond is higher than that of the MnCO bond. The initial dissociation of the Mncyclopentadienyl bond in the IRMPD is confirmed with trapping of Mn(CO) 3 and cyclopentadienyl radicals by C 5H 5R, CO and isobutane. The Mncyclopentadienyl dissociation occurs through effective IR multiple-photon excitation of ( η 5-C 5H 4R)Mn(CO) 3 to high vibrational states.

Crystal structure of a carbon monoxide sorption complex of dehydrated fully manganese(II)-exchanged zeolite X

Abstract The crystal structure of a carbon monoxide sorption complex of vacuum-dehydrated Mn 2+ -exchanged zeolite X, Mn 46 Si 100 Al 92 O 384 ·30CO ( a =24.715(8) A) has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd 3 at 21(1)°C. The complex was prepared by dehydration at 380°C and 2×10 −6 Torr for 3 days, followed by exposure at 21(1)°C to 270 Torr of carbon monoxide gas. The structure was determined in this atmosphere and was refined to the final error indices, R 1 =0.055 and R 2 =0.049 with 321 reflections for which I >3 σ ( I ). Mn 2+ ions are located at two different sites of high occupancy: 16 Mn 2+ ions fill site I at the centers of the double six-rings, and the remaining 30 Mn 2+ ions nearly fill site II in the supercage. Each of these latter Mn 2+ ions is recessed 0.30 A into the supercage from the plane of the three oxygens to which it is bound and coordinates linearly via C to a CO molecule [C–O=0.96(3) A] deeper in the supercage. Each site-II Mn 2+ ion is four-coordinate, to three framework oxygens and to one molecule of CO [Mn–C=2.57(3) A, Mn–O=2.130(9) A, O–Mn–O=118.1(5)° and O–Mn–C=98.0(3)°]. The Mn–C bond length is somewhat long, indicative of a relatively weak Mn–CO electrostatic interaction.

Solid phases in the cycling of manganese in eutrophic lakes: New insights from EXAFS spectroscopy

We have combined EXAFS spectroscopy with other methods such as x-ray diffraction, electron microscopy, and porewater analyses to study the mineralogical transformation of poorly crystallized manganese minerals at the oxic/anoxic boundary of the eutrophic Lake Sempach (Switzerland). Manganese oxide formed in the water column was identified as H +-birnessite offering a large amount of vacancies in the birnessite layers for cation sorption. EXAFS spectroscopy reveals reduced manganese in the top 2 mm of the sediment. Therefore, the reduction of MnO 2 must occur at similar rates as the sedimentation which is 2.5 mmol m −2 d −1 during summer. EXAFS-spectroscopy and microprobe analyses show that Mn is associated with authigenic (Ca,Mn) CO 3 and (Fe,Mn) 3(PO 4) 2*8H 2O-particles. The relative amount of Mn in these two phases was quantitatively determined by EXAFS-spectroscopy, yielding 55–60% Mn incorporated in carbonate and 40–45% Mn in phosphate particles. The average concentration of Mn amounts to 23 mol% in carbonate particles and 16 mol% in phosphate. With respect to the solid solutions, (Ca,Mn) CO 3 and (Fe,Mn ) 3(PO 4 ) 2 * H 2O, the porewater remains oversaturated from spring until autumn. Thus, dissolution of these phases is very unlikely. The remobilisation of Mn from the sediment into the deep water is, therefore, thought to be governed by other processes such as adsorption and desorption of Mn(II) on calcite surfaces.

Lithological and geochemical evidence of Fe and Mn pathways during deposition of Lower Proterozoic banded iron formation in the Krivoy Rog Basin (Ukraine)

Abstract Data on stratigraphy, chemical and mineral composition of siliciclastic and ferrugionus rocks of greenschist to epidote-amphibolite metamorphic grade, multi-order cyclicity and banding, isotopic composition of sulphur and carbon and other features of the Krivoy Rog Supergroup metasedimentary rocks are summarized. They provide an insight into the primary sources and the nature of siliciclastic and chemogenic components of banded iron formation (BIF), as well as on pathways of Fe, Mn and Si in the Krivoy Rog palaeobasin at the time of BIF accumulation. Skelevat and Saxagan iron-ore Groups were deposited in a single cyclic transgressive-regressive sequence, probably in a trough-like landlocked basin with complex bottom topography defined by syn-sedimentary faults inherited from the earlier rift structures. Variations in sea level, humidity of climate, continental run-off, oceanic water inflows etc. many times provoked the rapid facies changes ranging from sedimentation of land-derived siliciclastics to deposition of nearly pure chemogenic sediments of the oxide facies BIF in the deeper parts of the basin. Up to seven pairs of schist ( s -) and BIF ( f -) horizons were deposited in the Saxagan Group. Lateral variations of their thicknesses, distribution of free carbon in the rocks and other data indicate that only parts of the basin at a given time were optimal for chemical sedimentation; major part of dissolved Fe, Si and Mn was supplied by constant or event inflow of suboxic ocean water. The Mn content in the Krivoy Rog Supergroup BIFs could serve as an indicator of the fraction of total Fe that precipitated chemically as carbonate. The main part of Fe precipitation in form of Fe(III) hydroxide particles, possibly coated with amorphous silica, is due to a number of oxidation mechanisms operating in the photic surface water layer. On the basis of physicochemical considerations, it is concluded that the Mn CO 3 content in siderite ( c. 2 mol %) contained in the BIF rocks reflects a uniform dissolved Mn concentration ( c. 1 ppm) in the ocean and basin waters. Sedimentation of the typical association of Mg-Fe carbonates and silicates of the carbonate-silicate facies BIF could occur in the near-bottom water only in the case of strong enrichment in dissolved Fe(II) (up to 100–200 ppm) relative to the ocean water (1–10 ppm), which required a stratified brackish-water basin with an estuarine-type circulation. No enrichment in dissolved Mn(II) was possible until p O 2 in the atmosphere raised high enough for precipitation of particulate Mn oxide in the photic zone and its dissolution in the suboxic near-bottom waters.

One-Bond55Mn,13C Coupling Constants, a Correction

Previously published one-bond 55Mn,13C coupling constants have been recalculated using a revised lineshape fitting program, QUADR. The accuracy of the new data was confirmed by the simulation of quadrupole-broadened but resolved 13C and 19F spectra of the model complexes K3[Co(CN)6] and Li[AsF6]. The 55Mn,13C coupling constants lie in the range 128–189 Hz for Mn—CO bonds, 57–114 Hz for Mn—C(sp2) bonds and 35–79 Hz for Mn—C(sp3) bonds.

Sulphuric acid leaching of the Nsuta manganese carbonate ore

Sulphuric acid leaching of the Nsuta (Ghana) manganese carbonate ore was investigated at different temperatures and using various particle size fractions and acid concentrations. Results showed that both initial rate and overall extractions were affected by acid concentration, initial particle fraction and the temperature of leaching. Manganese carbonate dissolution in acid was more favoured at elevated temperatures. A study of the MnCO 3SO 4 system indicated the appearance of a MnSO 4 stability region between Mn 2+ and MnCO 3 predominance areas as the sulphate activity {S} exceeded unit molality. The territory increased mainly at the expense of Mn 2+ as sulphate activity increased. The practical implication of this is the probable formation of MnSO 4 in the particle pores and, therefore, the alteration of the mechanism/kinetics of leaching, as was experienced during tests with the Nsuta carbonate samples. It was also observed that the formation of MnSO 4 in the pores helped in the disintegration of the porous coarser particles during leaching.

Photomicrocalorimetry: Photosubstitution of carbonyl by phosphites in [Mn(η 5-C 5H 4CH 3)(CO) 3

A photomicrocalorimeter is described for studies of reactions involving oxygen and moisture-sensitive compounds in organic solvents. This calorimeter was used to investigate the thermochemistry of photochemical substitutions of a carbonyl in [Mn(η 5C 5H 4CH 3)(CO) 3] by P(OR) 3 (R  Ph or 1Pr). The measured reaction enthalpies in heptane (λ = 400 nm), ΔH r = −15.7 ± 0.5 and −18.6 ± 0.9 kJ mol −1, respectively, were identified with the bond dissociation enthalpy differences D(MnCO)  D[MnP(OPh) 3] and D(MnCO)  D[Mn-P(O iPr) 3] in solution. These results are discussed in terms of the basicity of the phosphates, spectroscopic data of the complexes (CO stretching frequencies), and the available thermochemical data for other transition metal-phosphorus(III) ligand interactions.

55Mn, 13C coupling constants of some σ‐ and π‐organomanganese complexes

Abstract55Mn, 13C coupling constants of σ‐ and π‐organomanganese pentacarbonyl, tetracarbonylphosphine and tricarbonyl complexes were determined by lineshape analysis of the 13CO and 13C(R) signals (R = alkyl, acyl or aryl) using the iterative lineshape fitting program QUADR. The 1J(55Mn, 13C) data are in the range 29–47 Hz for MnCO bonds and 2–28 Hz for MnR bonds. The 55Mn chemical shifts and linewidths are also reported.

The molecular structure of cyclopentadienyl manganese tricarbonyl determined by gas-phase electron diffraction

The molecular structure of cyclopentadienyl manganese tricarbonl, C5H5Mn(CO)3, has been studied by gas-phase electron diffraction at 70°C. Two models fit the experimental data equally well: model A, which allows for free rotation of the Mn(CO)3 moiety (that has C3v symmetry) about the MnX axis (X is the centre of the cyclopentadienyl ring), and model B, which has a staggered arrangement of the carbonyl groups with respect to the cyclopentadienyl ring. The final geometrical parameters for model A are: rg(MnC(ring)) = 2.149(3) Å, rg(MnCO) 1.808(3) Å, rg(CC) = 1.424(2) Å, rg(CO) = 1.148(3) Å, ∠(OCMnCO) = 92.0(0.5)° with an R-fa of 5.55%. The final geometrical parameters for model B are: rg(MnC(ring)) = 2.149(3) Å, rg(MnCO) = 1.808(3) Å, rg(CC) = 1.424(2) Å, rg(CO) = 1.148(2) Å, ∠(OC-Mn-CO) = 91.9(0.4)°, R = 5.55% from which it can be seen that the geometrical parameters show no significant difference from those obtained with model A. No definitive evidence was obtained for the HC bonds being bent out of the plane of the Cp ring. When the HCX angle was allowed to refine, a value of 1.7(3.4)° was obtained. A positive value indicates that the hydrogen atoms are on the same side of the ring as the manganese atom.

Infrared laser spectroscopy of jet-cooled methyl manganese pentacarbonyl

Infrared absorption spectra of jet-cooled CH3Mn(CO)5 and CD3Mn(CO)5 in the region of the two strongly allowed CO vibrations have been measured using diode lasers. Analysis of the spectra yielded values for the band centers and rotational constants for parallel bands of both isotopic species, and for the perpendicular band of CH3Mn(CO)5; the latter also provided an estimate of the Coriolis constant for this vibration. The spectra were consistent with essentially free rotation of the methyl group. The rotational constants were in close agreement with those derived from electron diffraction data: however, the B-rotational constants provide a revised estimate for the axial Mn–CO bond length.

Photodissociation dynamics of Mn2(CO)1 in solution on ultrafast time scales

A study of the photodissociation dynamics of Mn2(CO)10 and the vibrational relaxation of its subsequent photoproducts in solutions has been carried out using picosecond time-resolved laser techniques. The molecule predissociates in less than 2–3 ps after excitation with a 295 nm photon. Two dissociation channels are open for this excitation wavelength, namely, the Mn–Mn bond breaking and the Mn–CO bond breaking, generating internally hot ⋅Mn(CO)5 and Mn2(CO)9, respectively. These two species have a different absorption spectrum in the visible region and are probed independently by varying the probe laser wavelength. The vibrational relaxation of these nascent photoproducts is observed for the first time. In cyclohexane the vibrationally hot Mn2(CO)9 reaches thermal equilibrium with the solvent through two distinct decay channels with time constants of 15 and 170 ps, respectively. The vibrationally cold Mn2(CO)9 then persists for many nanoseconds. The vibrational relaxation is found to be faster in the 2-propanol solution with time constants of 10 and 145 ps. On the other hand, the ⋅Mn(CO)5 species cools down in less than 10 ps and then exists in the solution for many nanoseconds as well. This result indicates that energy transfer from the internally hot ⋅Mn(CO)5 species to the solvent is much faster than from Mn2(CO)9. Comparison is made with Cr(CO)5 in similar solvents.

Metal dimer chemistry: Me 3NO induced substitution reactions of (η 5-C 5H 5)MoMn(CO) 8. X-ray structure determination of (η 5-C 5H 5)MoMn(CO) 7[P(OMe) 3

Reaction of (η 5-C 5H 5)MoMn(CO) 8 ( 1) with P(OMe) 3 and t-BuNC in the presence of Me 3NO results in facile MoMn bond cleavage products as well as the synthesis of (η 5-C 5H 5)Mo(CO) 3Mn(CO) 4[P(OMe 3)] ( 3) in which the P(OMe) 3 occupies a site trans to the MoMn bond. The crystal structure of 3 is reported (space group P2 1/ c, a=13.064(4), b=7.1325(8), c=22.227(5) Å β=104.91(1)°. Final R and R w, values were 0.058 and 0.048 ( w= Kσ 2( F)). The non-bridged MoMn bond length is the largest reported to date (3.112(1) Å) and the equatorial MnCO bond lengths are longer than those in the patent unsubstituted dimer ( 1).

The chemistry of monoanionic carbaborane ligands. Synthesis, and molecular and electronic structure of [3,3,3-(CO) 3-4-SMe 2-3,1,2-MnC 2B 9H 10], and order-of-magnitude improved structure of (η-C 5H 5)Mn(CO) 3

The synthesis, and spectroscopic and structural characterisation of a transition metal complex of, formally, a monoanionic carbaborane ligand are described. Two molecules of [3,3,3-(CO) 3-4-SMe 2-3,1,2-MnC 2B 9H 10] crystallise in the triclinic space group P 1 , with a 7.154(4), b 8.7890(21), c 13.366(3) Å, α 91.438(19), β 101.21(3), γ 110.69(3)°, at 185 ± 1 K. R = 0.0352 for 3859 observed reflections. The carbamanganaborane has an essentially icosahedral polyhedral geometry, and the pendant SMe 2 unit is oriented such that the S lone pair…H(1) δ+ interaction is maximised. The average OCMnCO angle is 89.91°. A redetermination of the structure of the known species CpMn(CO) 3 affords molecular parameters of high precision. Space group P2 1/ a with a 11.941(7), b 6.981(5), c 10.798(7) Å, β 117.97(5)°, Z = 4, R = 0.0418 for 1960 significant reflections measured at 185 ± 1 K. In this compound OCMnCO is wider, average 92.14°. Charge iterated EHMO calculations suggest that the anionic carbaborane ligand may be represented by a form in which a charge of −1.5 e on the five facial atoms is partially offset by a charge of +0.3 e on the pendant S atom. EHMO/FMO calculations confirm that the carbaborane is a better electron donor than the Cp ligand to the {Mn(CO) 3} unit, and indicate that the additional electron density on Mn resides in fragment orbitals that are antibonding between C and O. In particular, CO → Mn σ donation is restricted in the carbaborane compound relative to the Cp compound. Consistent with the results of these calculations, ν(CO) values of the former compound are measurably lower than those of the latter species.

Cluster synthesis by photolysis of R 3PAuN 3 IV. Synthesis and structure of [(Ph 3PAu) 4Mn(CO) 4]PF 6

Photolysis of R 3PAuN 3 in the presence of Mn 2(CO) 10 yields the cationic cluster compounds [(Ph 3PAu) 4Mn(CO) 4] + (1) and [(Ph 3PAu) 6Mn(CO) 3] + (2), which can be separated by column chromatography. Compound 1 crystallizes from CH 2Cl 2-diisopropylether after addition of PF 6 − as 1 · PF 6· 0.5CH 2Cl 2 in the triclinic space group P1̄ with a = 1709.8(6) pm, b = 2017.3(7) pm, c = 1180.3(7) pm, α = 106.42(3)°, β = 98.81(4)°, γ = 102.82(4)°, V = 3704.9 × 10 6 pm 3, Z = 2. The central unit of 1 is a trigonal bipyramid Au 4Mn with the manganese atom in equatorial position. The AuAu distances are in the range 277.3 to 292.2 pm. The manganese atom forms two short bonds of 263.3 and 264.0 pm to the axial gold atoms and two longer bonds of 272.3 and 273.3 pm to the equatorial neighbors. A d 2sp 3 hybridization can be assumed for the manganese atom. Four of the orbitals are used for the MnCO σ-bonds. The remaining two are then pointing approximately to the center of the Au 3 triangular faces.