14221-06-8

Usage

Chemical Properties

yellow to greenish needle-like crystals or

Physical properties

Molybdenum (II) Acetate adopts the same Chinese lantern structure as related acetate dimers such as rhodium (II) acetate, copper (II) acetate, and chromium (II) acetate. Each Mo(II) center in Mo2(O2CCH3)4 has four d valence electrons. These eight d-electrons form one σ, two π bonds, and one δ bond, creating a bonding electron configuration of σ2π4δ2. Each of these bonds are formed by the overlapping of pairs of d orbitals.The four acetate groups bridge the two metal centers. The Mo-O bond between each Mo(II) center and O atom from acetate has a distance of 2.119 ?, and the Mo-Mo distance between the two metal centers is 2.0934 ?.

Uses

Molybdenum(II) acetate dimer is generally used as an intermediate compound in a process to form other quadruply bonded molybdenum compounds.

Application

Mo2(O2CCH3)4 is generally used as an intermediate compound in a process to form other quadruply bonded molybdenum compounds The acetate ligands can be replaced to give new compounds such as [Mo2Cl8]4- and Mo2Cl4[P(C4H9)3]4.

Preparation

Mo2(O2CCH3)4is prepared by treating molybdenum hexa carbonyl (Mo (CO)6) with acetic acid. The process strips CO ligands from hexacarbonyl results in the oxidation of Mo (0) to Mo (II). 2 Mo(CO)6 + 4 HO2CCH3 → Mo2(O2CCH3)4 + 12 CO + 2 H2 Trinuclear clusters are byproducts. The reaction of HO2CCH3 and Mo(CO)6 was first investigated by Bannister et al. in 1960. At the time, quadruple metal-metal bonds had not yet been discovered, so these authors proposed that "Mo(O2CCH3)2 was tetrahedral. This perspective changed with Mason's characterization .

Upstream product

• 105502-46-3 bis[dichloro(μ-bis(diphenylphosphino)amine)molybdenum(II)] 
• 127-09-3 sodium acetate 
• 64-19-7 acetic acid 
• 31355-55-2 trichlorotris(tetrahydrofuran)molybdenum(III) 
• 108-24-7 acetic anhydride 
• 13939-06-5 molybdenum hexacarbonyl 
• 104-15-4 toluene-4-sulfonic acid 
• 1493-13-6 trifluorormethanesulfonic acid 
• 16925-25-0 sodium hexafluoroantimonate 
• 80594-72-5 [Mo(CO)4Br₂]2 

Downstream Products

• 64508-32-3 β-Mo2Cl4(dppe)2 
• 80822-44-2 trans-Mo₂(O₂CCH₃)2Cl₂(PPh₃)2 
• 116791-09-4 Mo₂(O₂CCH₃)2Cl₂(dppe) 
• 80339-94-2 tetrakis{N-(2,6-dimethylphenyl)acetamido}bis(tetrahydrofuran)dimolybdenum(II) 
• 80327-51-1 tetrakis{N-(2,6-dimethylphenyl)acetamido}(pyridine)dimolybdenum(II)-benzene (1/1) 
• 76037-17-7 bis(acetato)bis[N,N'-bis(2,6-xylyl)acetamidinato]dimolybdenum tetrakis(tetrahydrofuranate) 
• 105502-46-3 bis[dichloro(μ-bis(diphenylphosphino)amine)molybdenum(II)] 
• 178383-67-0 Mo₂(O₂CC₆H₃-2-Cl-4-NO₂)4 

Relevant academic research and scientific papers

Trimolybdenum cluster compounds with two capping ethylidyne groups

Three compounds containing equilateral-triangular trimolybdenum clusters capped on both sides by ethylidyne (CCH3) groups are described: [Mo3(CCH3)2(O2CCH3) 6(H2O)3]SbF6·3H2O (1), [Mo3(CCH3)2(O2CCH3) 6(H2O)3](CF3SO3) 2 (2), and [Mo3(CCH3)2(O2CCH3) 6(H2O)3](p-CH3C6H 4SO3)2·10H2O (3). All three are obtained by suitable workup of the reaction mixture after refluxing Mo(CO)6 with a 10:1 v/v mixture of acetic acid and acetic anhydride. For the last two permanganate oxidation is used. The crystal structures of the three compounds have been solved and refined. In 1, where there are five electrons for the Mo3 cluster, the Mo-Mo bond orders are 5/6 and the mean Mo-Mo distance is 2.814 (5) A?; this is about 0.06 A? longer than that in a closely related cluster with Mo-Mo bond orders of 1.0. In 2 and 3, which each contain a bicapped Mo3 cluster with only four electrons, and hence a bond order of 2/3, the mean Mo-Mo distances are 2.883 (1) A? and 2.892 (1) A?, i.e., about 0.13 A? longer than for the Mo-Mo bonds of order 1.0. The cation in 1 has one unpaired electron showing an essentially constant g factor slightly above 2.0 in the range 4-300 K according to bulk susceptibility measurements. It shows no EPR spectrum but has a sharp 360-MHz 1H NMR spectrum in which the resonance of the O2CCH3 protons is shifted to 14 ppm downfield while that of the CCH3 protons is broadened and shifted 85 ppm downfield. The cations in 2 and 3 appear to be paramagnetic, but the temperature dependence is unusual and still under study. The cation gives an 1H NMR spectrum with lines at 15.6 and 27.1 ppm with relative intensities of 3.3 to 1.0.

Dimolybdenum tetracarboxylates as auxiliary chromophores in chiroptical studies of vic-diols

The aim of the present work was to check the suitability of dimolybdenum carboxylates, other than commonly used [Mo2(OAc)4], as auxiliary chromophores for determining the absolute configuration of optically active vic-diols by means of electronic circular dichroism (ECD). To this end, a set of dimolybdenum tetracarboxylates was synthesized, and subsequently, the two most promising compounds were selected, namely dimolybdenum tetrakis(μ-pivalate) and tetrakis(μ-isovalerate). The selection was based on their solubility in commonly used solvents, their stability in solution, their tolerance to air exposure, as well as their utility for dichroic studies. The stability of the obtained in situ chiral complexes was verified by measuring the dependence of ECD, UV-vis, and NMR spectra on time, temperature, and concentration. We have shown that the ECD spectra of diverse vic-diols with these complexes are suitable for configurational assignment based on the correlation between signs of Cotton effects (CEs) arising in the spectra and the stereostructure of the ligand. Furthermore, to aid in the interpretation of experimental results, a separate set of DFT calculations has been incorporated to provide additional insight into the structure of the chiral complexes involved. In contrast to the earlier assumptions, experiments showed that the chelating mode of ligation is preferred for the studied complexes.

Hierarchically Ordered Two-Dimensional Coordination Polymers Assembled from Redox-Active Dimolybdenum Clusters

Coordination polymers (CPs) supporting tunable through-framework conduction and responsive properties are of significant interest for enabling a new generation of active devices. However, such architectures are rare. We report a redox-active CP composed of two-dimensional (2D) lattices of coordinatively bonded Mo2(INA)4 clusters (INA = isonicotinate). The 2D lattices are commensurately stacked and their ordering topology can be synthetically tuned. The material has a hierarchical pore structure (pore sizes distributed between 7 and 33 ?) and exhibits unique CO2 adsorption (nominally Type VI) for an isotherm collected at 195 K. Furthermore, cyclic voltammetry and electrokinetic analyses identify a quasi-reversible feature at E1/2 = -1.275 V versus ferrocene/ferrocenium that can be ascribed to the [Mo2(INA)4]0/-1 redox couple, with an associated standard heterogeneous electron transfer rate constant ks = 1.49 s-1. The tunable structure, porosity, and redox activity of our material may render it a promising platform for CPs with responsive properties.

Preparation of core-shell coordination molecular assemblies via the enrichment of structure-directing codes of bridging ligands and metathesis of metal units

A series of molybdenum- and copper-based MOPs were synthesized through coordination-driven process of a bridging ligand (3,3′-PDBAD, L1) and dimetal paddlewheel clusters. Three conformers of the ligand exist with an ideal bridging angle between the two carboxylate groups of 0° (H2α-L1), 120°(H2β-L1), and of 90°(H2γ-L1), respectively. At ambient or lower temperature, H2L1 and Mo2(OAc)4 or Cu2(OAc)4 were crystallized into a molecular square with γ-L1 and Mo2/Cu2 units. With proper temperature elevation, not only the molecular square with γ-L1 but also a lantern-shaped cage with α-L1 formed simultaneously. Similar to how Watson-Crick pairs stabilize the helical structure of duplex DNA, the core-shell molecular assembly possesses favorable H-bonding interaction sites. This is dictated by the ligand conformation in the shell, coding for the formation and providing stabilization of the central lantern shaped core, which was not observed without this complementary interaction. On the basis of the crystallographic implications, a heterobimetallic cage was obtained through a postsynthetic metal ion metathesis, showing different reactivity of coordination bonds in the core and shell. As an innovative synthetic strategy, the site-selective metathesis broadens the structural diversity and properties of coordination assemblies.

Microwave-assisted synthesis of dimolybdenum tetracarboxylates and a decanuclear osmium cluster

An improved method for the synthesis of dimolybdenum tetracarboxylates has been developed. The standard procedure for the preparation of these compounds involves extended reflux (up to 20 h) of a mixture of Mo(CO)6 and the appropriate carboxylic acid, along with its anhydride, under an inert atmosphere. Using a microwave reactor and a closed vessel, Mo2(acetate)4, Mo2(propionate)4 and Mo2(benzoate)4 have been prepared in superior yields in less than 1 h. Furthermore, this new method does not require the use of the acid anhydride or the use of an inert gas. An improved method for the preparation of [N(PPh3)2]2[Os10C(CO)24] directly from Os3(CO)12 has also been developed. The published synthesis of this osmium cluster calls for the pyrolysis of Os3(CO)11(py) for 64 h. Microwave irradiation of a mixture of Os3(CO)12 and diglyme in a closed vessel yields the desired product in just over 1 h.

Syntheses and structures of di(carboxylato)hexakis(acetonitrile)-dimolybdenum(II) bis(tetrafluoroborate) and trans-[di(μ-acetato)-di(acetonitrile)di(μ-bis(diphenylphosphino)amine) dimolybdenum (II)] bis(tetrafluoroborate)

Di(carboxylato)hexakis(acetonitrile)dimolybdenum(II) bis(tetrafluoroborate) s, [Mo2(μ-O2CR)2(CH3CN) 6](BF4)2(R = CH3,CH2Cl, C(CH3)3, CF3) (3a-d), are easily accessible by reacting [Mo2(CH3CN)8](BF4)4 (2) with a stoichiometric amount or a slight excess of the appropriate carboxylic acid and anhydride in acetonitrile. A large excess of carboxylic acid leads to the formation of tetracarboxylates. As an example cis-[Mo2(μ-O2CCH2Cl)2(CH 3CN)6](BF4)2 (3b) has been structurally characterized. Crystallographic data are as follows: space group: I42d (No. 122), a = b = 10.733(2), c = 59.448(5) A?, V = 6848(2) A?3, Z = 8, d(Mo-Mo) = 2.140(1) A?. Trans-[Mo2(μ-O2CCH3)2(dppa) 2(CH3CN)2](BF4)2 (4) can be synthesized from cis-[Mo2(μ-O2CCH3)2(CH 3CN)6](BF4)2 (3a) and bis(diphenylphosphino)amine (dppa) at room temperature. This result contradicts earlier reports where bulky diphosphines such as dppm (sterically very similar to dppa) did not lead to bis-diphosphine products. Furthermore our results indicate that in all the syntheses reported to date for [Mo2(μ-O2CCH3)2(LL) 2](BF4)2 type-compounds [Mo2(μ-O2CCH3)2(CH 3CN)6](BF4)2 acts as the precursor compound. Crystallographic data for 4 are as follows: P21/c (No. 14), a = 19.683(3), b = 15.129(2), c = 21.084(1) A?, β = 101.30(1)°, V = 6848(2) A?3, Z = 4. There are two independent molecules of the cation in the unit cell, d(Mo-Mo) = 2.133(1) and 2.136(1) A?.

Lewis acid enhanced axial ligation of [Mo2]4+ complexes

We report here the syntheses, X-ray crystal structures, electrochemistry, and density functional theory (DFT) single-point calculations of three new complexes: tetrakis(monothiosuccinimidato)dimolybdenum(II) [Mo 2(SNO5)4, 1a], tetrakis(6-thioxo-2-piperidinonato) dimolybdenum(II) [Mo2(SNO6)4, 1b], and chlorotetrakis(monothiosuccinimidato)pyridinelithiumdimolybdenum(II) [pyLiMo2(SNO5)4Cl, 2-py]. X-ray crystallography shows unusually short axial Mo2-Cl bond lengths in 2-py, 2.6533(6) A, and dimeric 2-dim, 2.644(1) A, which we propose result from an increased Lewis acidity of the Mo2 unit in the presence of the proximal Li + ion. When 2-py is dissolved in MeCN, the lithium reversibly dissociates, forming an equilibrium mixture of (MeCNLiMo2(SNO5) 4Cl) (2-MeCN) and [Li(MeCN)4]+[Mo 2(SNO5)4Cl]- (3). Cyclic voltammetry was used to determine the equilibrium lithium binding constant (room temperature, K eq = 95 ± 1). From analysis of the temperature dependence of the equilibrium constant, thermodynamic parameters for the formation of 2-MeCN from 3 (ΔH = -6.96 ± 0.93 kJ mol-1 and ΔS = 13.9 ± 3.5 J mol-1 K-1) were extracted. DFT calculations indicate that Li+ affects the Mo-Cl bond length through polarization of metal-metal bonding/antibonding molecular orbitals when lithium and chloride are added to the dimolybdenum core.

Synthesis and crystal structure of [Re(CO)3(μ-CH3CO2)(THF)]4

A tetrameric complex [Re(CO)3(μ-CH3CO2)(THF)]4 (1) is formed in high yield when the reaction product of Re(CO)5Cl with acetic acid in refluxing 1,2-dichlorobenzene is dissolved in THF. The use of Re2(CO)10 instead of rhenium pentacarbonyl chloride also affords 1. The characterization of 1·3THF·0.5C6H14 has been accomplished by X-ray crystallography. The structure of the tetrameric molecule 1 consists of four rhenium(I) atoms bridged by four acetate ligands. The coordination of each metal center is fulfilled by three CO groups and one THF molecule in a way that all carbonyls are trans to oxygen atoms. The geometry of each acetate bridge is anti-syn providing a Re to Re separation of 5.40 A. This bonding mode is seen here for the first time in rhenium carboxylates. Different coordination types for Re-RCO2 interaction are also discussed in the paper.

Synthesis, X-ray Structure Analysis and Spectroscopic Characterization of trans-Aquabis(μ-benzoato-κ2 O:O′) bis[μ-N,N′-bis(4-methoxyphenyl) formamidinato-κ2 N:N′] dimolybdenum(II)

Abstract: The title compound, trans-Mo2(DAniF)2(OOCC6H5)2(H2O) (I) has a quadruply bonded Mo2 4+ unit equatorially coordinated by two N,N′-bis(4-methoxyphenyl)formamidinate (referred as DAniF) ligands and two benzoate (OOCC6H5) groups in transverse, and axially coordinated by one aqua oxygen atom. The compound crystallizes in the space group C2/c with one molecule in the asymmetric unit and features a Mo–Mo bond length of 2.0983(4) ?, which is typical for dimolybdenum quadruple bonds. In the crystal, the offsetstacking between pairs of phenyl rings creating a one-dimensional linear chain perpendicular to the Mo–Mo directions, with a distance between phenyl rings of 3.44?? and the center-to-center distance of 3.83??. The coordinated water oxygen atoms act as donors and uncoordinated methoxyl group oxygen atoms act as acceptors in intermolecular O–H?O hydrogen bonds.stacking between phenyl rings assemble the molecules into a three-dimensional framework. Graphical Abstract: The offsetstacking between phenyl rings of quadruply bonded Mo2 4+ paddle-wheel molecules create a one-dimensional linear chain. [Figure not available: see fulltext.].

Dicarboxylate-bridged (Mo2)n (n = 2, 3, 4) paddle-wheel complexes: Potential intermediate building blocks for metal-organic frameworks

The treatment of the dimeric paddle-wheel (PW) compound [Mo 2(NCCH3)10][BF4]41 with oxalic acid (0.5 equiv.), 1,1-cyclobutanedicarboxylic acid (1 equiv.), 5-hydroxyisophthalic acid (1 equiv.) (m-bdc-OH) or 2,3,5,6- tetrafluoroterephthalic acid (0.5 or 1 equiv.) leads to the formation of macromolecular dicarboxylate-linked (Mo2)n entities (n = 2, 3, 4). The structure of the compounds depends on the length and geometry of the organic linkers. In the case of oxalic acid, the dimeric compound [(CH 3CN)8Mo2(OOC-COO)Mo2(NCCH 3)8][BF4]62 is formed selectively, whereas the use of 2,3,5,6-tetrafluoroterephthalic acid affords the square-shaped complex [(CH3CN)6Mo2(OOC-C 6F4-COO)]4[BF4]83. Bent linkers with a bridging angle of 109° and 120°, respectively, lead to the formation of the molecular loop [(CH3CN)6Mo 2(OOC-C4H6-COO)]2[BF 4]44 and the bowl-shaped molecular triangle [(CH 3CN)6Mo2(m-bdc-OH)]3[BF 4]65. All complexes are characterised by X-ray single crystal diffraction, NMR (1H, 11B, 13C and 19F) and UV-Vis spectroscopy.