Polymeric assembling through reciprocal metal-η-arene π-interactions: Synthesis and X-ray characterization of [Hg(RPhNNNPhR′)2Py]2 (R = NO2, R′ = F), an asymmetric bis diaryl-substituted triazenide-pyridinyl complex of Hg(II)

Hg(SCN)₂ reacts with 3-(2-fluorophenyl)-1-(4-nitrophenyl)triazene in tetrahydrofuran in the presence of triethylamine to give orange crystals of [Hg^II(RPhNNNPhR′)₂Py]₂ (R = NO₂, R′ = F), a new polymeric triazenide-pyridinyl complex of Hg(II) with reciprocal metal-η²-arene π-interactions. The crystal structure belongs to the triclinic space group , and the lattice of [Hg^II(RPhNNNPhR′)₂Py]₂ can be viewed as a supramolecular unidimensional assembling of tectonic [Hg^II(RPhNNNPhR′)₂Py] units linked through intermolecular metal-arene π interactions and non-classical C-H?O hydrogen bonding.     

Synthesis, X-ray crystal structure, and reactivity of Pd2(μ-dotpm)2 (dotpm = bis(di-ortho-tolylphosphino)methane)

Alkylation of PdCl₂(dotpm) (dotpm = bis(di-ortho-tolylphosphino)methane) with n-butyllithium produces the binuclear Pd(0) complex Pd₂(μ-dotpm)₂ and the elimination byproducts 1-butene, cis-2-butene, trans-2-butene, butane, and octane. The dibutyl complex, Pd(dotpm)(n-Bu)₂, is presumed to be the reaction intermediate. The crystal structure of Pd₂(μ-dotpm)₂ reveals that the methylene groups of the bridging dotpm ligands are located on opposite sides of the Pd₂P₄ unit, forming an 8-membered ring that is in an elongated chair conformation. The four phosphorus atoms are not coplanar, and the P1-P2-P3-P4 ring has a torsion angle of 13.8°, which minimizes the spatial interactions among the o-tolyl rings. The Pd-Pd bond distance is 2.8560(6) Å, which indicates that there is a weak “closed-shell” bonding interaction between the d¹⁰-d¹⁰ metal centers. Each palladium atom has a nearly linear geometry, and the eight methyl groups of the dotpm ligands shield the open coordination sites on the metal centers. Four methyl groups shield the metal atoms above and below the Pd₂P₄ ring cavity, and four methyl groups block the open metal sites outside of the Pd₂P₄ ring. The Pd₂(μ-dotpm)₂ complex readily undergoes oxidative addition of dichloromethane to form the rigid A-frame complex Pd₂Cl₂(μ-CH₂)(μ-dotpm)₂.     

Insertion reaction of elemental sulfur into the Ln–C bond: Synthesis and characterization of [(C5H4SiMe2Bu)2Ln(μ-SR)]2 (R = Me,Ln = Yb,Er, Dy,Y; R = Bu,Ln = Yb,Dy)

Treatment of (C₅H₄SiMe₂^tBu)₂LnR with 1 equiv of elemental sulfur in toluene at ambient temperature gives dimeric complexes [(C₅H₄SiMe₂^tBu)₂Ln(μ-SR)]₂ [R = Me, Ln = Yb (1), Er (2), Dy (3), Y (4); R = ⁿBu, Ln = Yb (5), Dy (6)]. All these complexes have been characterized by elemental analysis, IR and mass spectroscopies. The structures of complexes 1, 3, 5 and 6 are also determined through X-ray single crystal diffraction analysis, indicating that only one sulfur atom from elemental sulfur inserts into Ln–C σ-bond.     

Spin fluctuations and orbital ordering in quasi-one-dimensional α-Cu(dca)2(pyz) {dca = dicyanamide = N(CN)2; pyz = pyrazine}, a molecular analogue of KCuF3

The magnetic properties of α-Cu(dca)₂(pyz) were examined by magnetic susceptibility, magnetization, inelastic neutron scattering (INS), muon-spin relaxation (μSR) measurements and by first-principles density functional theoretical (DFT) calculations and quantum Monte Carlo (QMC) simulations. The χ versus T curve shows a broad maximum at 3.5 K, and the data between 2 and 300 K is well described by an S = 1/2 Heisenberg uniform chain model with g = 2.152(1) and J/k_B = −5.4(1) K. μSR measurements, conducted down to 0.02 K and as a function of longitudinal magnetic field, show no oscillations in the muon asymmetry function A(t). This evidence, together with the lack of spin wave formation as gleaned from INS data, suggests that no long-range magnetic order takes place in α-Cu(dca)₂(pyz) down to the lowest measured temperatures. Electronic structure calculations further show that the spin exchange is significant only along the Cu–pyz–Cu chains, such that α-Cu(dca)₂(pyz) can be described by a Heisenberg antiferromagnetic chain model. Further support for this comes from the M versus B curve, which is strongly concave owing to the reduced spin dimensionality. α-Cu(dca)₂(pyz) is a molecular analogue of KCuF₃ owing to d_x2-y2${\text{d}}_{x^2-y^2}$ orbital ordering where nearest-neighbor magnetic orbital planes of the Cu²⁺ sites are orthogonal in the planes perpendicular to the Cu–pyz–Cu chains.     

Syntheses,structures, and optical properties of heteroselenometallic W–Se–Ag polymer compounds {[Et4N][(μ-WSe4)Ag]}n and {[Ln(Me2SO)8][(μ3-WSe4)3Ag3]}n (Ln = Pr,Er)

The one-dimensional linear polymer W–Se–Ag compound {[Et₄N][(μ-WSe₄)Ag]}_n (1) was obtained from the reaction of [Et₄N]₂[WSe₄] and AgNO₃ in a mixed solvent, MeCN/DMF (1:10). Treatment of a solution of 1 in Me₂SO with Ln(NO₃)₃ · 6H₂O resulted in the formation of a helical chain polymer compound {[Ln(Me₂SO)₈][(μ₃-WSe₄)₃Ag₃]}_n (Ln = Pr 2, Er 3). The solid-state structures of the three polymer compounds 1, 2, and 3 have been established by X-ray crystallography. The third-order non-linear optical properties of the linear polymer compound 1 were determined by z-scan techniques with 7 ns pulses at 532 nm.     

Segregated aromatic π-π stacking interactions involving fluorinated and non-fluorinated benzene rings: Cu(py)2(pfb)2 and Cu(py)2(pfb)2(H2O) (py = pyridine and pfb = pentafluorobenzoate)

The syntheses, physical characterization and crystal structures of two new molecular copper(II) complexes of composition [Cu(C₅H₅N)₂(C₇F₅O₂)₂] (1) and [Cu(C₅H₅N)₂(C₇F₅O₂)₂(H₂O)] (2) (C₅H₅N = py = pyridine and C₇F₅O₂⁻ = pfb = pentafluorobenzoate) are reported. Single-crystal X-ray structure determinations revealed that in 1, the Cu²⁺ ion, which lies on a crystallographic inversion centre, is coordinated to two py molecules and two oxygen atoms from two monodentate pfb anions, resulting in a trans-CuN₂O₂ square planar geometry. In 2, the Cu²⁺ ion is also coordinated to two py and two pfb species in addition to a water molecule in the apical site of a distorted CuN₂O₃ square pyramid. In the crystal packing, both 1 and 2 show segregated aromatic π-π stacking interactions in which (py + py) and (pfb + pfb) ring-pairings are seen, but no (py + pfb) pairings occur. Crystal data: 1: C₂₄H₁₀CuF₁₀N₂O₄, M_r = 643.88, space group , a = 8.0777 (3) Å, b = 8.0937 (3) Å, c = 10.5045 (5) Å, α = 90.916 (3)°, β = 93.189 (2)°, γ = 118.245 (3)°, V = 603.36 (4) Å³, Z = 1. 2: C₂₄H₁₂CuF₁₀N₂O₅, M_r = 661.90, space group , a = 7.5913 (5) Å, b = 15.6517 (6) Å, c = 21.1820 (14) Å, α = 95.697 (4)°, β = 94.506 (2)°, γ = 91.492 (4)°, V = 2495.2 (3) Å³, Z = 4.     

A study of β-hydride abstraction from alkanediyl homobimetallic complexes [{Cp(CO)2Fe}2{μ-(CnH2n)}] (n = 4-10, Cp = η-C5H5)

The alkyl-bridged iron(II) complexes [{Cp(CO)₂Fe}₂{μ-(C_nH_2n)}] (n = 6-10, Cp = η⁵-C₅H₅) undergo both single and double hydride abstraction when reacted with one equivalent of Ph₃CPF₆ to give both the monocationic complexes, [{Cp(CO)₂Fe}₂{μ-(C_nH_2n−1)}]PF₆, and the dicationic complexes, [{Cp(CO)₂Fe}₂{μ-(C_nH_2n−2)}](PF₆)₂. The ratios of monocationic to dicationic complexes decrease with the increase in the value of n. The complexes where n = 4 and 5 undergo only single hydride abstraction under similar conditions. When reacted with two equivalents of Ph₃CPF₆, the complexes where n = 6-10 undergo double hydride abstraction to give dicationic complexes only. In contrast, the complex where n = 5 gives equal amounts of the monocationic and the dicationic complexes, while the complex where n = 4 only gives the monocationic complex. ¹H and ¹³C NMR data show that in the monocationic complexes one metal is σ-bonded to the carbenium ion moiety while the other is bonded in a η²-fashion forming a chiral metallacylopropane type structure. In the dicationic complexes both metals are bonded in the η²-fashion. The monocationic complexes where n = 4-6, react with methanol to give η¹-alkenyl complexes[Cp(CO)₂Fe(CH₂)_nCHCH₂] (n = 2-4) as the major products and σ-bonded ether products [{Cp(CO)₂Fe}₂{μ-(CH₂)_nCH(OCH₃)CH₂}] as the minor products. The complex where n = 8 reacted with iso-propanol to give the η¹-alkenyl complex [Cp(CO)₂Fe(CH₂)₆CHCH₂]. The dicationic complexes where n = 5, 8 and 9 were reacted with NaI to give the respective α, ω-dienes and [Cp(CO)₂FeI].     

Diverse coordination of two ligands in ferromagnetic [Cu(μ-HCO2)2(3-pyOH)]n and [Cu2(μ-HCO2)2(μ-3-pyOH)2(3-pyOH)2(HCO2)2]n

Two novel polynuclear complexes with methanoate anions and 3-hydroxypyridine ligands [Cu(μ-HCO₂)₂(3-pyOH)]_n (1) and [Cu₂(μ-HCO₂)₂(μ-3-pyOH)₂(3-pyOH)₂(HCO₂)₂]_n (2), respectively, were synthesized and characterized. The central copper atom in 1 is surrounded by four methanoates and a 3-pyOH molecule, forming a square-pyramidal CuO₃NO chromophore. All the methanoates are bidentate and serve as bridges between the adjacent copper ions via syn-anti and anti–anti coordination. The basal square coordination axes are formed by O(syn), N(3-pyOH) (1.974(2), 2.016(2) Å) and O(anti), O(anti) (1.945(2), 1.960(2) Å), while the third O(anti) (2.247(2) Å) is on the top of the pyramid. A ferromagnetic transition with an exchange constant 2J/k_B = 9.2 cm⁻¹ is found for 1 below 20 K. This interaction probably takes place through two syn-anti methanoates extended in a chain through the 2D structure. On the other hand, two monoatomic Cu–O–Cu intra-dinuclear asymmetric (1.986(2), 2.415(2) Å) bridges of two methanoates in [Cu₂(HCO₂)₄(3-pyOH)₄] (2) are present. An elongated distorted octahedral coordination sphere around each copper(II) atom is completed by an additional monodentate terminal methanoate (1.975(2) Å), two N-coordinated 3-pyOH (2.005(2), 2.002(2) Å) and the third weakly O-coordinated 3-pyOH (2.732(2) Å). Although a shorter Cu?Cu distance is noticed in 2 than in 1 (4.690(1) Å 1, 3.442(1) Å 2), much weaker ferromagnetism is found in 2.     

Di- and tri-nuclear molybdenum-palladium complexes bearing strong π-acceptor “P-N-P” ligands, MeN{P(OR)2}2 (R = CH2CF3 or Ph)

The dipalladium complexes, [PdCl(μ-MeN{P(OR)₂}₂)]₂ (R = CH₂CF₃, 1a; Ph, 1b) react with [Mo₂(η⁵-C₅H₅)₂(CO)₆] in boiling benzene to afford the molybdenum-palladium heterometallic complexes, [(η⁵-C₅H₅)(CO)Mo(μ-MeN{P(OR)₂}₂)₂PdCl] (R = CH₂CF₃, 3a; Ph, 3b), [(η⁵-C₅H₅)Mo(μ₃-CO)₂(μ-MeN{P(OR)₂}₂)₂Pd₂Cl], (R = CH₂CF₃, 5a; Ph, 5b), [(η⁵-C₅H₅)(Cl)Mo(μ₂-CO)(μ₂-Cl)(μ-MeN{P(OR)₂}₂)PdCl], (R = CH₂CF₃, 6a; Ph, 6b) and also the mononuclear complex [Mo(CO)Cl(η⁵-C₅H₅)(κ²-MeN{P(OR)₂}₂)], (R = Ph, 4b). These complexes have been separated by column chromatography and are characterised by elemental analysis, IR, ¹H, ³¹P{¹H} NMR data. The structures of 1a, 3a, 4b, 5b and 6a have been confirmed by single crystal X-ray diffraction. The CO ligands in 5b and 6a adopt a semi-bridging mode of bonding; the Mo-CO distances (1.95-1.97 Å) are shorter than the Pd-CO distances (2.40-2.48 Å). The Pd-Mo distances fall in the range, 2.63-2.86 Å. The reaction of [Mo₂(η⁵-C₅H₅)₂(CO)₆] with MeN{P(OPh)₂}₂ in toluene gives [Mo₂(CO)₄(η⁵-C₅H₅)₂(κ¹-MeN{P(OPh)₂}₂)₂] (2) in which the diphosphazane acts as a monodentate ligand.     

Effect of solvent on reactions of Cp2Zr{(μ-H)2BHR}2 and Cp2ZrH{(μ-H)2BHR} (R = CH3, Ph) with B(C6F5)3

The effect that a solvent has on reactions of Cp₂Zr{(μ-H)₂BHR}₂ and Cp₂ZrH{(μ-H)₂BHR} (R = CH₃, Ph) with B(C₆F₅)₃ has been studied. From the reaction in benzene the metathesis product Cp₂Zr{(μ-H)₂B(C₆F₅)₂}₂, 2, was isolated. In the case of diethyl ether, different hydride abstraction products, including [Cp₂Zr(OEt₂){(μ-H)₂BHPh}][HB(C₆F₅)₃], 3, [Cp₂Zr(OEt₂){(μ-H)₂BHCH₃}][HB(C₆F₅)₃], 4, [Cp₂Zr(OEt₂){(μ-H)₂BH₂}][HB(C₆F₅)₃], 5, and [Cp₂Zr(OEt)(OEt₂)][HB(C₆F₅)₃], 6, were isolated depending on the starting zirconocene complex. The diethyl ether molecules of 3-6 are weakly coordinated to Zr and displaced in THF solution. Isolation of 3 and 4 is attributed to their fast precipitation from the reaction mixture, which prevented further reactions from occurring. In addition to the hydride abstraction, a hydride metathesis was also involved in the formation of 5. Time-elapsed ¹¹B NMR studies indicate that 3 and 4 are the intermediates on the pathway to 5 and 6. The molecular structures of 2-6 were determined by single-crystal X-ray diffraction.     

Centrosymmetric [Mn2(CO)6(μ-thpymS)2] (thpymS = tetrahydropyrimidine-2-thionato) as a synthon to mixed-metal clusters

Reaction of [Mn₂(CO)₉(NCMe)] with tetrahydropyrimidine-2-thione (thpymSH) at 25 °C furnishes the mono- and dinuclear complexes [Mn(CO)₄(κ¹:η¹-SCNHC₃H₆NCO)] (2) and [Mn₂(CO)₆(μ-thpymS)₂] (1), respectively. Carbon-nitrogen coupling is observed in compound 2 resulting in the formation of κ¹:η¹-SCNHC₃H₆NCO ligand while compound 1 adopts a centrosymmetric structure. Reaction of 1 with [Os₃(CO)₁₀(NCMe)₂] at 80 °C affords the mixed Mn-Os cluster [MnOs₃(CO)₁₃(μ₃-thpymS)] (3) which possesses a butterfly skeleton of four metal atoms whereas with Ru₃(CO)₁₂ at 110 °C gives the mixed Mn-Ru complex [MnRu₃(CO)₁₄(μ₄-S)(κ¹:η¹-thpym)] (4). In contrast, treatment of 1 with Fe₃(CO)₁₂ at 80 °C furnishes two triiron complexes [Fe₃(CO)₉(μ₃-S)(μ₃-κ¹:η¹-C₄H₆N₂)] (5) and [Fe₃(CO)₈(μ₃-S)₂(η¹-C₄H₈N₂)] (6). The former also results from the direct reaction of thpymSH with Fe₃(CO)₁₂ and reacts with H₂S to afford 6. The molecular structures of all these new complexes have been determined by X-ray diffraction studies.     

Palladium nitrosyl carboxylate clusters: Synthesis and reactivity. X-ray structures of Pd4(μ-CO)2(μ-NO)(μ-RCO2)5 (R = Pr, Bu)

New palladium nitrosyl carboxylate complexes Pd₈(CO)_4−m(NO)_m(NO₂)₄(RCO₂)₈ (m = 2, 4) were obtained by the treatment of palladium carbonyl carboxylates clusters cyclo-Pd_n(μ-CO)_n(μ-RCO₂)_n (n = 6) (1) with gaseous nitrogen monoxide. These complexes are the products of CO substitution in early described Pd₈(CO)₄(NO₂)₄(RCO₂)₈ clusters. By adding an excess of corresponding acid to reaction mixture Pd₄(CO)₂(NO)(RCO₂)₅ complexes were obtained, their structures were determined by X-ray diffraction analysis. These clusters are intermediate products of transformation of 6-nuclear initial clusters into various 8-nuclear complexes. This fact demonstrates that carboxylate ligands can be used as stabilizers for intermediate unstable polynuclear palladium compounds.     

Cluster-containing carbon-rich molecules: Reactions of ruthenium cluster carbonyls with {Au(PR3)}2(μ-CCCC) (R = Ph, tol)

Complexes containing C₄ ligands attached to one or two AuRu₃ clusters by conventional σ, 2π interactions have been obtained from reactions between (R₃P)AuC≡CC≡CAu(PR₃) (R = Ph, tol) or Au(C≡CC≡CH){P(tol)₃} and either Ru₃(CO)₁₂, Ru₃(CO)₁₀(NCMe)₂ or Ru₃(μ-dppm)(CO)₁₀. The X-ray determined structures of {(R₃P)AuRu₃(CO)₉}₂(μ₃,η²:μ₃,η²-C₂C₂) [R = Ph (1) (three solvates), tol (2)], AuRu₃{μ₃,η²-C₂C≡CAu(PPh₃)}(CO)₉(PPh₃) (3) and {(Ph₃P)AuRu₃(μ-dppm)(CO)₇} (μ₃,η²:μ₃,η²-C₂C₂){Ru₃(μ-H)(μ-dppm)(CO)₇} (4) are reported.     

Reactions of Cu3(dppm)3(μ3-OH)(ClO4)2 (dppm = bis-(diphenylphosphino) methane) with Soft Heterocumulenes

The reaction of [Cu₃(dppm)₃(μ₃-OH)](ClO₄)₂ (1) with heterocumulenes (XCS; X = NPh, NMe and S) has been studied. The μ₃-OH ligand inserts into PhNCS and MeNCS only in the presence of methanol. Insertion products are formed in accord with earlier observations made with copper(I)-aryloxides. On heating, the insertion products convert to a S bridged cluster [Cu₄(dppm)₄(μ₄-S)](ClO₄)₂ (8), having a tetrameric core. However, in the reaction with CS₂, 1 is converted to 8 even at room temperature in the presence of methanol. On the other hand, the dimeric complex [Cu₂(dppm)₂(CH₃CN)₄](ClO₄)₂, reacts with CS₂ to give (diphenylphosphinomethyl)-diphenylphosphine sulfide, Ph₂P-CH₂-P(S)Ph₂ (dppmS), which forms the complex [Cu(dppmS)₂]ClO₄ (9). A single crystal X-ray crystallographic study of 9, the first copper(I) complex of dppmS has been taken up to confirm the mono-oxidation of the dppm ligand and the nuclearity of the complex. Reactions of complex 1 with heterocumulenes and with elemental sulfur, are compared.     

trans-dinitro- and trans-dinitratoruthenium complexes [RuNO(NH3)2(NO2)2(OH)] and [RuNO(NH3)2(H2O)(NO3)2]NO3·H2O

Methods for the synthesis of trans-diammino complexes [RuNO(NH₃)₂(NO₂)₂(OH)] (I) and [RuNO(NH₃)₂(H₂O)(NO₃)₂](NO₃)·H₂O (II) are suggested. The compounds were studied by IR spectroscopy and X-ray phase and X-ray structural analyses. Crystal data: space group P-1; a = 6.2328(2) ?, b = 11.0488(3) ?, c = 11.0981(4) ?, α = 71.942(1)°, β = 83.291(1)°, γ = 86.877(1)° (I); space group P2₁; a = 6.6290(2) ?, b = 13.4389(5) ?, c = 7.0180(2) ?, β 114.281(1)° (II). Complex II readily lost some part of crystal water on storage in open air. Original Russian Text Copyright ? 2009 by M. A. Il’in, E. V. Kabin, V. A. Emel’yanov, I. A. Baidina, and V. A. Vorob’yov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 2, pp. 341–348, March–April, 2009.     

[Cu(dca)2(en)]n: a two-dimensional copper(II) coordination polymer with both μ1,5-dca and pseudo-μ1,3-dca bridges

A copper(II)-dicyanamide (dca=dicyanamide anion, [N(CN)₂]⁻) compound, [Cu(dca)₂(en)]_n (1) (en=ethylene diamine), has been synthesized and its structure has been determined by single X-ray diffraction analysis. It crystallizes in the monoclinic space group C2/c with unit cell dimensions: β=99.499°, Z=8, and 1 is the first coordination polymer containing both μ_1,5-dca and pseudo-μ_1,3-bridging dca. The adjacent copper atoms are connected by dca with μ_1,5-bridging mode to form a chain structure. Furthermore, the chains are cross linked via the pseudo-μ_1,3-bridging dca into a 2D layer structure. Magnetic characterization of 1 suggests that the complex exhibits a weak antiferromagnetic interaction between the copper(II) ions.     

[M(dipicH2)(H2O)3], M = Ni,Cu, Zn (dipicH2 = dipicolinic acid) – A combined crystallographic,spectroscopic and computational study

Cationic metal complexes of dipicolinic acid (dipicH₂) are stabilized by [Ce(dipic)₃]²⁻ ions in the three isomorphous crystals [M(dipicH₂)(OH₂)₃][Ce(dipic)₃] · 3H₂O (M = Ni, 1; Cu, 2; Zn, 3). Magnetic dilution provided by the bulky anions leads to well-resolved EPR spectra in polycrystalline samples of 2. The cations have 4+2 coordination, the carbonyl atom of the carboxylic acid groups coordinating weakly from trans positions. In the case of 2 this steric distortion is augmented by Jahn–Teller distortion. All the three structures are satisfactorily modelled by calculations based on density functional theory (DFT). The switch of the Jahn–Teller axis upon deprotonation of the complex, leading to the neutral species Cu(dipic)(H₂O)₃, is also reproduced by DFT. Electronic transition energies as well as the g-tensor component of the d⁹ complex obtained are in good agreement with experiment. However, the calculated hyperfine coupling constants are in error. DFT also fails to satisfactorily account for the electronic transition in the d⁸ ion in 1.     

Cu(NO3)2(La(NO3)3)-CO(NH2)2-H2O三元体系的等温溶度研究

本文首次报道三元体系Cu(NO₃)₂-CO(NH₂)₂-H₂O(30℃)和La(NO₃)₃-CO(NH₂)₂-H₂O(25℃)的等温溶度及饱和溶液、折光率,绘制相应的溶度图及折光率-组成图。体系中发现有组成为Cu(NO₃)₂·4CO(NH相似文献   

A general route for the synthesis of hydrido-carboxylate complexes of the type MH(CO)(κ-OCOR)(PPh3)2 [M = Ru,Os; R = CH3, CH2Cl,C6H5, CH(CH3)2] and their use as precatalysts for hydrogenation and hydroformylation reactions

The synthesis and solid-state IR, ¹H and ³¹P{¹H} NMR spectroscopic characterization of complexes of the type MH(CO)(κ³-OCOR)(PPh₃)₂ [M = Ru, Os; R = CH₃, CH₂Cl, C₆H₅ and CH(CH₃)₂] are reported in this paper. These compounds were obtained by reaction of the respective cationic complex [MH(CO)(NCMe)₂(PPh₃)₂]BF₄ with the sodium salt of the corresponding carboxylic acid in a 1:1 v/v dichloromethane/methanol solution at room temperature. The spectroscopic data of these complexes and some DFT calculations reveal an octahedral geometry with a bidentated carboxylate, two equivalent triphenylphosphines in a mutually trans positions, a linear hydride and a linear carbonyl both in the cis-positions of the coordination sphere. The catalytic results indicate that these complexes are efficient and regioselective precatalysts for the quinoline hydrogenation and for the hydroformylation of 1-hexene, under mild reaction conditions (130 °C and 4 atm H₂ and 120 °C and 15 atm H₂/CO, respectively). For benzothiophene hydrogenation, the osmium complexes showed low activities whereas the analogous ruthenium complexes were catalytically inactive under somewhat more drastic reaction conditions to those of the quinoline hydrogenation (140 °C and 10 atm H₂).