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Landaeta VR, Horsley Downie TM, Wolf R. Low-Valent Transition Metalate Anions in Synthesis, Small Molecule Activation, and Catalysis. Chem Rev 2024; 124:1323-1463. [PMID: 38354371 PMCID: PMC10906008 DOI: 10.1021/acs.chemrev.3c00121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 10/09/2023] [Accepted: 10/09/2023] [Indexed: 02/16/2024]
Abstract
This review surveys the synthesis and reactivity of low-oxidation state metalate anions of the d-block elements, with an emphasis on contributions reported between 2006 and 2022. Although the field has a long and rich history, the chemistry of transition metalate anions has been greatly enhanced in the last 15 years by the application of advanced concepts in complex synthesis and ligand design. In recent years, the potential of highly reactive metalate complexes in the fields of small molecule activation and homogeneous catalysis has become increasingly evident. Consequently, exciting applications in small molecule activation have been developed, including in catalytic transformations. This article intends to guide the reader through the fascinating world of low-valent transition metalates. The first part of the review describes the synthesis and reactivity of d-block metalates stabilized by an assortment of ligand frameworks, including carbonyls, isocyanides, alkenes and polyarenes, phosphines and phosphorus heterocycles, amides, and redox-active nitrogen-based ligands. Thereby, the reader will be familiarized with the impact of different ligand types on the physical and chemical properties of metalates. In addition, ion-pairing interactions and metal-metal bonding may have a dramatic influence on metalate structures and reactivities. The complex ramifications of these effects are examined in a separate section. The second part of the review is devoted to the reactivity of the metalates toward small inorganic molecules such as H2, N2, CO, CO2, P4 and related species. It is shown that the use of highly electron-rich and reactive metalates in small molecule activation translates into impressive catalytic properties in the hydrogenation of organic molecules and the reduction of N2, CO, and CO2. The results discussed in this review illustrate that the potential of transition metalate anions is increasingly being tapped for challenging catalytic processes with relevance to organic synthesis and energy conversion. Therefore, it is hoped that this review will serve as a useful resource to inspire further developments in this dynamic research field.
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Affiliation(s)
| | | | - Robert Wolf
- University of Regensburg, Institute
of Inorganic Chemistry, 93040 Regensburg, Germany
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Alvarez MA, García ME, García-Vivó D, Guerra AM, Ruiz MA. C≡N and N≡O Bond Cleavages of Acetonitrile and Nitrosyl Ligands at a Dimolybdenum Center to Render Ethylidyne and Acetamidinate Ligands. Inorg Chem 2024; 63:3207-3211. [PMID: 38306699 PMCID: PMC10880054 DOI: 10.1021/acs.inorgchem.3c03697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 01/26/2024] [Accepted: 01/27/2024] [Indexed: 02/04/2024]
Abstract
Extended reduction of [Mo2Cp2(μ-Cl)(μ-PtBu2)(NO)2] (1) with Na(Hg) in acetonitrile (MeCN) at room temperature resulted in an unprecedented full cleavage of the C≡N bond of a coordinated MeCN molecule to yield the vinylidene derivative Na[Mo2Cp2(μ-PtBu2)(μ-CCH2)(NO)2], which upon protonation with (NH4)PF6 gave the ethylidyne complex [Mo2Cp2(μ-PtBu2)(μ-CMe)(NO)2] [Mo1-Mo2 = 2.9218(2) Å] in a selective and reversible way. Controlled reduction of 1 at 273 K yielded instead, after protonation, the 30-electron acetamidinate complex [Mo2Cp2(μ-PtBu2)(μ-κN:κN'-HNCMeNH)(μ-NO)]PF6 [Mo1-Mo2 = 2.603(2) Å], in a process thought to stem from the paramagnetic MeCN-bridged intermediate [Mo2Cp2(μ-PtBu2)(μ-NCMe)(NO)2], followed by a complex sequence of elementary steps including cleavage of the N≡O bond of a nitrosyl ligand.
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Affiliation(s)
- M. Angeles Alvarez
- Departamento de Química
Orgánica e Inorgánica, Instituto Universitario de Química
Organometálica “Enrique Moles”, Universidad de Oviedo, E33071 Oviedo, Spain
| | - M. Esther García
- Departamento de Química
Orgánica e Inorgánica, Instituto Universitario de Química
Organometálica “Enrique Moles”, Universidad de Oviedo, E33071 Oviedo, Spain
| | - Daniel García-Vivó
- Departamento de Química
Orgánica e Inorgánica, Instituto Universitario de Química
Organometálica “Enrique Moles”, Universidad de Oviedo, E33071 Oviedo, Spain
| | - Ana M. Guerra
- Departamento de Química
Orgánica e Inorgánica, Instituto Universitario de Química
Organometálica “Enrique Moles”, Universidad de Oviedo, E33071 Oviedo, Spain
| | - Miguel A. Ruiz
- Departamento de Química
Orgánica e Inorgánica, Instituto Universitario de Química
Organometálica “Enrique Moles”, Universidad de Oviedo, E33071 Oviedo, Spain
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Takemoto S, Yoshii K, Yamano T, Tsurusaki A, Matsuzaka H. Metal-metal multiple bond formation induced by σ-acceptor Lewis acid ligands. Chem Commun (Camb) 2021; 57:923-926. [PMID: 33393949 DOI: 10.1039/d0cc07278h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of [Cp*Ru(μ-NHPh)]2 (Cp* = η5-C5Me5) with Lewis acids of the type MX2 (M = Zn, Sn, Pb; X = Cl, OTf) affords Ru2 → M donor-acceptor adducts characterized as π complexes of a Ru[double bond, length as m-dash]Ru double bond with M(ii) Lewis acids. The results illustrate for the first time the ability of σ-acceptor Lewis acid ligands to induce the formation of a metal-metal multiple bond via stabilizing dative interactions.
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Affiliation(s)
- Shin Takemoto
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
| | - Kaname Yoshii
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
| | - Takahiro Yamano
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
| | - Akihiro Tsurusaki
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
| | - Hiroyuki Matsuzaka
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
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Alvarez MA, García ME, García-Vivó D, Ramos A, Ruiz MA, Toyos A. N-O Bond Activation and Cleavage Reactions of the Nitrosyl-Bridged Complexes [M 2Cp 2(μ-PCy 2)(μ-NO)(NO) 2] (M = Mo, W). Inorg Chem 2018; 57:15314-15329. [PMID: 30461277 DOI: 10.1021/acs.inorgchem.8b02647] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The title complexes (1a,b) were prepared in two steps by first reacting the hydrides [M2Cp2(μ-H)(μ-PCy2)(CO)4] with [NO](BF4) in the presence of Na2CO3 to give dinitrosyls [M2Cp2(μ-PCy2)(CO)2(NO)2](BF4), which were then fully decarbonylated upon reaction with NaNO2 at 323 K. An isomer of the Mo2 complex having a cisoid arrangement of the terminal ligands ( cis-1a) was prepared upon irradiation of toluene solutions of 1a with visible-UV light at 288 K. The structure of these trinitrosyl complexes was investigated using X-ray diffraction and density functional theory (DFT) calculations, these revealing a genuine pyramidalization of the bridging NO that might be associated in part to an increase of charge at the N atom and anticipated a weakening of the N-O bond upon reaction with bases or reducing reagents. Complexes 1a,b reacted with [FeCp2](BF4) to give first the radicals [M2Cp2(μ-PCy2)(μ-NO)(NO)2](BF4) according to CV experiments, which then underwent H-abstraction to yield the nitroxyl-bridged complexes [M2Cp2(μ-PCy2)(μ-κ1:η2-HNO)(NO)2](BF4), alternatively prepared upon protonation with HBF4·OEt2. The novel coordination mode of the nitroxyl ligand in these products was thermodynamically favored over its tautomeric hydroximido form, according to DFT calculations, and similar nitrosomethane-bridged cations [M2Cp2(μ-PCy2)( μ-κ1:η2-MeNO)(NO)2]+ were prepared by reacting 1a,b with CF3SO3Me or [Me3O]BF4. Complexes 1 reacted with M(Hg) (M = Zn, Na) in tetrahydrofuran to give the amido-bridged derivatives [M2Cp2(μ-PCy2)(μ-NH2)(NO)2] with retention of stereochemistry, a transformation also induced by using mild O atom scavengers such as CO and phosphites in the presence of water. In the absence of water, phosphites accomplished a deoxygenation of the bridging NO of the Mo2 complexes to yield the phosphoraniminato-bridged derivatives [Mo2Cp2(μ-PCy2){μ-NP(OR)3}(NO)2] (R = Et, Ph), also with retention of stereochemistry.
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Affiliation(s)
- M Angeles Alvarez
- Departamento de Química Orgánica e Inorgánica/IUQOEM , Universidad de Oviedo , E-33071 Oviedo , Spain
| | - M Esther García
- Departamento de Química Orgánica e Inorgánica/IUQOEM , Universidad de Oviedo , E-33071 Oviedo , Spain
| | - Daniel García-Vivó
- Departamento de Química Orgánica e Inorgánica/IUQOEM , Universidad de Oviedo , E-33071 Oviedo , Spain
| | - Alberto Ramos
- Departamento de Química Orgánica e Inorgánica/IUQOEM , Universidad de Oviedo , E-33071 Oviedo , Spain
| | - Miguel A Ruiz
- Departamento de Química Orgánica e Inorgánica/IUQOEM , Universidad de Oviedo , E-33071 Oviedo , Spain
| | - Adrián Toyos
- Departamento de Química Orgánica e Inorgánica/IUQOEM , Universidad de Oviedo , E-33071 Oviedo , Spain
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Trapping of an Heterometallic Unsaturated Hydride: Structure and Properties of the Ammonia Complex [MoMnCp(μ-H)(μ-PPh2)(CO)5(NH3)]. INORGANICS 2018. [DOI: 10.3390/inorganics6040125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Complexes displaying multiple bonds between different metal atoms have considerable synthetic potential because of the combination of the high electronic and coordinative unsaturation associated to multiple bonds with the intrinsic polarity of heterometallic bonds but their number is scarce and its chemistry has been relatively little explored. In a preliminary study, our attempted synthesis of the unsaturated hydrides [MoMCp(μ-H)(μ-PR2)(CO)5] from anions [MoMCp(μ-PR2)(CO)5]− and (NH4)PF6 yielded instead the ammonia complexes [MoMCp(μ-H)(μ-PR2)(CO)5(NH3)] (M = Mn, R = Ph; M = Re, R = Cy). We have now examined the structure and behaviour of the MoMn complex (Mo–Mn = 3.087(3) Å) and found that it easily dissociates NH3 (this requiring some 40 kJ/mol, according to DFT calculations), to yield the undetectable unsaturated hydride [MoMnCp(μ-H)(μ-PPh2)(CO)5] (computed Mo–Mn = 2.796 Å), the latter readily adding simple donors L such as CNR (R = Xyl, p-C6H4OMe) and P(OMe)3, to give the corresponding electron-precise derivatives [MoMnCp(μ-H)(μ-PPh2)(CO)5(L)]. Thus the ammonia complex eventually behaves as a synthetic equivalent of the unsaturated hydride [MoMnCp(μ-H)(μ-PPh2)(CO)5]. The isocyanide derivatives retained the stereochemistry of the parent complex (Mo–Mn = 3.0770(4) Å when R = Xyl) but a carbonyl rearrangement takes place in the reaction with phosphite to leave the entering ligand trans to the PPh2 group, a position more favoured on steric grounds.
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Alvarez MA, García ME, García-Vivó D, Ruiz MA, Toyos A. E-H Bond Activation and Insertion Processes in the Reactions of the Unsaturated Hydride [W 2Cp 2(μ-H)(μ-PPh 2)(NO) 2]. Inorg Chem 2018; 57:2228-2241. [PMID: 29411970 DOI: 10.1021/acs.inorgchem.7b03111] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reactions of the title complex (1) with different p-block element (E) molecules was examined. Compound 1 reacted with BH3·THF at room temperature to give the trihydride [W2Cp2(μ-H)H2(μ-PPh2)(NO)2], which formally results from hydrogenation of 1, a reaction that actually does not take place when neat dihydrogen is used. Clean E-H bond oxidative addition, however, took place when 1 was reacted with HSnPh3, to give the related dihydride stannyl derivative [W2Cp2(μ-H)H(μ-PPh2)(NO)2(SnPh3)]. In contrast, the reaction of 1 with HSPh involved H2 elimination to give the thiolate-bridged complex [W2Cp2(μ-SPh)(μ-PPh2)(NO)2], while that with (p-tol)C(O)H resulted in insertion of the aldehyde to yield the related alkoxide complex [W2Cp2{μ-OCH2(p-tol)}(μ-PPh2)(NO)2]. Insertion also prevailed in the reactions of 1 with CNtBu, which, however, involved the competitive formation of new C-H or N-H bonds, to give a mixture of formimidoyl and aminocarbyne derivatives, [W2Cp2(μ-κ1:η2-HCNtBu)(μ-PPh2)(NO)2] (W-W = 3.0177(2) Å) and [W2Cp2{μ-C(NHtBu)}(μ-PPh2)(NO)2] (W-W = 2.9010(4) Å), respectively, even though the latter was thermodynamically preferred, according to density functional theory calculations. The former represents the first structurally characterized complex displaying a formimidoyl or iminoacyl ligand in the alkenyl-like μ-κ1:η2 coordination mode. The reaction of 1 with diazomethane proceeded with N2 elimination and C-H coupling to yield the agostic methyl-bridged complex [W2Cp2(μ-κ1:η2-CH3)(μ-PPh2)(NO)2] (calculated W-W = 2.923 Å), whereas the reaction with N2CH(SiMe3) proceeded with insertion of the diazoalkane to give the corresponding hydrazonide complex [W2Cp2{μ-NH(NCHSiMe3)}(μ-PPh2)(NO)2] (W-W = 2.8608(4) Å). The latter was converted under alkaline conditions to the methyldiazenide derivative [W2Cp2{μ-N(NMe)}(μ-PPh2)(NO)2] (W-W = 2.8730(2) Å), in a process involving hydrolysis of the C-Si bond coupled with a 1,3-H shift from N to C.
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Affiliation(s)
- M Angeles Alvarez
- Departamento de Química Orgánica e Inorgánica/IUQOEM, Universidad de Oviedo , E-33071 Oviedo, Spain
| | - M Esther García
- Departamento de Química Orgánica e Inorgánica/IUQOEM, Universidad de Oviedo , E-33071 Oviedo, Spain
| | - Daniel García-Vivó
- Departamento de Química Orgánica e Inorgánica/IUQOEM, Universidad de Oviedo , E-33071 Oviedo, Spain
| | - Miguel A Ruiz
- Departamento de Química Orgánica e Inorgánica/IUQOEM, Universidad de Oviedo , E-33071 Oviedo, Spain
| | - Adrián Toyos
- Departamento de Química Orgánica e Inorgánica/IUQOEM, Universidad de Oviedo , E-33071 Oviedo, Spain
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Angeles Alvarez M, Esther García M, García-Vivó D, Ruiz MA, Toyos A. Structure and dynamics of heterometallic clusters derived from addition of metal carbonyl fragments to the unsaturated hydride [W 2Cp 2(μ-H)(μ-PPh 2)(NO) 2]. Dalton Trans 2017; 46:15317-15329. [PMID: 29068454 DOI: 10.1039/c7dt03580b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The title complex reacted with [Fe2(CO)9] to give the trinuclear derivative [FeW2Cp2(μ-H)(μ-PPh2)(CO)4(NO)2] (W-W = 3.044(1) Å) as a result of full insertion of the 16-electron Fe(CO)4 fragment into the tricentric W-H-W bond of the parent substrate. In contrast, the reactions with the THF adducts [M(CO)5(THF)] (M = W, Mo) and [MnCp'(CO)2(THF)] (Cp' = C5H4Me) yielded the μ3-hydride derivatives [MW2Cp2(μ3-H)(μ-PPh2)(CO)5(NO)2] (W-W = 3.006(1) to 3.164(1) Å for the W3 compound) and [MnW2Cp2Cp'(μ3-H)(μ-PPh2)(CO)2(NO)2] respectively, all of them resulting from addition (rather than insertion) of the corresponding 16-electron fragment to the W2H moiety of the parent compound. Density Functional Theory calculations revealed that edge- and face-bridged hydride clusters were of similar energy in the W2Fe system, while the face-bridged structure was significantly more stable (by more than ca. 40 kJ mol-1) for the W3 system. Both clusters displayed fast rearrangement in solution involving a flapping movement of the puckered PW2M core of these molecules. This was combined, in the W2Fe cluster, with fast exchange between the almost isoenergetic edge- and face-bridged hydride isomers. The reactions of the title compound with several carbonyl dimers were also examined as an additional synthetic approach to the rational synthesis of heterometallic clusters, but were unsuccessful except in the case of [Co2(CO)8], which reacted at 253 K in the dark to give a mixture of the binuclear complex [CoWCp(μ-PPh2)(CO)4(NO)] (Co-W = 2.8623(6) Å) and the trinuclear cluster [CoW2Cp2(μ-PPh2)(CO)4(NO)2] (W-W = 3.1654(4) Å; W-Co = 2.638(1), 2.829(1) Å), the latter resulting from formal replacement of the hydride ligand with the 17-electron fragment Co(CO)4, which displayed an asymmetric binding to the W2 centre.
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Affiliation(s)
- M Angeles Alvarez
- Departamento de Química Orgánica e Inorgánica/IUQOEM, Universidad de Oviedo, E-33071 Oviedo, Spain.
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Alvarez MA, García ME, García-Vivó D, Rueda MT, Ruiz MA, Toyos A, Vega MF. Terminal vs. bridging coordination of CO and NO ligands after decarbonylation of [W 2Cp 2(μ-PR 2)(CO) 3(NO)] complexes (R = Ph, Cy). An experimental and computational study. Dalton Trans 2017; 46:10440-10451. [PMID: 28748981 DOI: 10.1039/c7dt02243c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Compounds [M2Cp2(μ-PPh2)(CO)3(NO)] (M = Mo, W) were prepared by reacting the corresponding radicals [M2Cp2(μ-PPh2)(CO)4] with NO, and displayed a terminal, linear NO ligand arranged cis to the P-donor ligand (Mo-Mo = 3.1400(7) Å). The related PCy2-bridged complex [W2Cp2(μ-PCy2)(CO)3(NO)] was prepared in a one-pot, three step procedure first involving deprotonation of the hydride complex [W2Cp2(μ-H)(μ-PCy2)(CO)4] with K[BH(sec-Bu)3], then oxidation of the resulting salt K[W2Cp2(μ-PCy2)(CO)4] with [FeCp2]BF4 at 243 K, and eventually by reacting the so-formed radical [W2Cp2(μ-PCy2)(CO)4] with NO. Photochemical decarbonylation of the Mo2 complex gave intractable mixtures of products. In contrast, photolysis of the ditungsten complexes yielded the corresponding dicarbonyls [W2Cp2(μ-PR2)(μ-κ1:η2-CO)(CO)(NO)] (R = Ph, Cy) as major products, which were characterized spectroscopically. The latter reacted readily with P(OMe)3 to give the corresponding derivatives [W2Cp2(μ-PR2)(CO)2(NO){P(OMe)3}], displaying a cisoid conformation of the P-donor ligands (P-W-P = 83.7(1)° when R = Cy). Density functional theory calculations on [W2Cp2(μ-PCy2)(μ-κ1:η2-CO)(CO)(NO)] and several potential isomers revealed that this electron-precise molecule (W-W = 3.121 Å) is almost isoenergetic with an unsaturated isomer having a μ-κ1:κ1-NO ligand (W-W = 2.677 Å) but their interconversion has a large kinetic barrier. It was concluded that formation of the κ1:η2-CO-bridged isomers in the photolytic experiment is favoured by the cisoid disposition of NO and PR2 ligands at the parent tricarbonyls, which precludes the NO ligand from easily rearranging into a bridging position after decarbonylation. The above calculations also revealed that the CO ligand is much better suited than NO for the μ-κ1:η2 coordination mode, since it can establish stronger end-on and side-on interactions with the dimetal centre.
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Affiliation(s)
- M Angeles Alvarez
- Departamento de Química Orgánica e Inorgánica/IUQOEM, Universidad de Oviedo, E-33071 Oviedo, Spain.
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