Transition Metal Cluster Complexes Research Articles

Biomimetic Transition Metal Cluster Complexes: Synthetic Studies and Applications in the Reduction of Inert Small Molecules

Abstract Transition metal cluster complexes, particularly those containing iron and sulfur, are used as catalysts for the biological reduction of inert small molecules such as N2 and CO2. The structures of these biological clusters are complicated and the protein backbones around the clusters often play important roles in catalysis, hence reproducing or mimicking the enzymatic functions with synthetic cluster complexes remains a challenge. Appropriate assumptions and hypotheses on the relationships between the structures and functions of biological clusters are needed to develop synthetic molecular catalysts inspired by enzymes. This account reviews recent studies by the author and his coworkers on iron-containing biomimetic cluster complexes. Cubic Mo-Fe-S clusters supported by bulky cyclopentadienyl ligands on molybdenum were designed and synthesized, and their Fe sites captured and catalytically converted N2 under reducing conditions. Iron-hydride clusters, which are relevant to the active species of biological and industrial nitrogen fixation, also served as catalysts for the reduction of N2. Furthermore, various metal-sulfur clusters, ranging from a structural mimic of the complex active site of the N2-reducing enzyme to a simple and cubic [Fe4S4] cluster, were found to catalyze the biologically inaccessible direct conversion of CO2 to short-chain hydrocarbons. These studies have demonstrated the potential utility of biomimetic approaches to the catalytic reduction of inert small molecules, through the rational design and synthesis of simple yet appropriate iron-containing cluster complexes.

Palladium cluster complex [Pd13(μ4-C7H7)6]2+ (C7H7 = tropylium) with an fcc-close-packed cuboctahedral Pd13 core and isomers: theoretical insight into ligand-control of the Pd13 core structure.

One of the challenging targets in today's chemistry is size-, shape- and metal-atom packing-controlled synthesis of nano-scale transition metal cluster complexes because key factors governing these features have been elusive. Here, we present a DFT study on a recently synthesized palladium cluster complex [Pd13(μ4-C7H7)6]2+ (named Cubo-μ4; C7H7 = tropylium) with an fcc-close-packed cuboctahedral Pd13 core and possible isomers. The stability decreases in the order Cubo-μ4 > [Pd13(μ3-C7H7)3(μ4-C7H7)3]2+ with an hcp-close-packed anticuboctahedral Pd13 core (Anti-μ3,4) > [Pd13(μ3-C7H7)6]2+ with a non-close packed icosahedral Pd13 core (Ih-μ3) > [Pd13(μ4-C7H7)6]2+ with an anticuboctahedral Pd13 core (Anti-μ4) > [Pd13(μ3-C7H7)6]2+ with a cuboctahedral Pd13 core (Cubo-μ3). This ordering disagrees with the stability of the Pd13 core. The key factor governing the stability and metal-atom packing manner of these Pd13 cluster complexes is not the stability of the Pd13 core but the interaction energy between the Pd13 core and the [(C7H7)6]2+ ligand shell. The interaction energy is mainly determined by the charge-transfer from the Pd13 core to the [(C7H7)6]2+ ligand shell and the coordination mode of the C7H7 ligand (μ3- vs. μ4-coordination bond). In the μ4-coordination, all seven C atoms of the C7H7 ligand interact with four Pd atoms of the Pd4 plane using two CC double bonds and one π-allyl moiety. On the other hand, in the μ3-coordination, one or two C atoms of C7H7 cannot form bonding interaction with the Pd atom of the Pd3 plane. Thus, the use of appropriate capping ligands is one of the key points in the synthesis of nano-scale metal cluster complexes.

α-Pyridinyl Alcohols, α,α'-Pyridine Diols, α-Bipyridinyl Alcohols, and α,α'-Bipyridine Diols as Structure Motifs Towards Important Organic Molecules and Transition Metal Complexes.

The preparation and use of pyridinyl alcohols as ligands showed incredible increment in the past three decades. Important property of pyridinyl alcoholato ligands is their strong basicity, which is mainly due to the lack of resonance stabilization of the corresponding anion. This strongly basic anionic nature gives them high ability to make bridges between metal centers rather than to bind to only one metal center in a terminal fashion. They are needed as ligands due to their ability to interact with transition metals both covalently (with oxygen) and hemilabile coordination (through nitrogen). The review focuses on the wide application of α-pyridinyl alcohols, α,α'-pyridine diols, α- bipyridinyl alcohols, and α,α'-bipyridine diols as structure motifs in the preparation of important organic molecules which is due to their strongly basic anionic nature. It is clear from the review that in addition to their synthetic utility in the homogeneous and asymmetric catalytic reactions, the preparation of the crown ethers, cyclic and acyclic ethers, coordinated borates (boronic esters), pyridinyl-phosphine ligands, pyridinyl-phosphite ligands, and pyridinyl-phosphinite ligands is the other broad area of application of pyridinyl alcohols. In addition to the aforementioned applications they are used for modeling mode of action of enzymes and some therapeutic agents. Their strongly basic anionic nature gives them high ability to make bridges between metal centers rather than to bind to only one metal center in a terminal fashion in the synthesis of transition metal cluster complexes. Not least numbers of single molecule magnets that can be used as storage of high density information were the result of transition metal complexes of pyridinyl alcoholato ligands.

Synthesis, structural and magnetic characterisation of iron(ii/iii), cobalt(ii) and copper(ii) cluster complexes of the polytopic ligand: N-(2-pyridyl)-3-carboxypropanamide

Herein we describe the synthesis, structural and magnetic characterisation of three transition metal cluster complexes that feature the polytopic ligand N-(2-pyridyl)-3-carboxypropanamide (H2L): [Fe3(III)Fe2(II)(HL)6(O)(H2O)3][ClO4]5·3MeCN·4H2O, 1, [Co8(HL)8(O)(OH)4(MeOH)3(H2O)]-[ClO4]3·5MeOH·2H2O, 2, and [Cu6(L(ox))4(MeOH)(H2O)3]·MeOH, 3. Complex 1 is a mixed valence penta-nuclear iron cluster containing the archetypal {Fe3(III)O} triangular basic carboxylate cluster at its core, with two Fe(II) ions above and below the core coordinated to three bidentate pyridyl-amide groups. The structure of the octanuclear Co(II) complex, 2, is based upon a central Co4 square with the remaining four Co(II) centres at the 'wing-tips' of the complex. The cluster core is replete with bridging oxide, hydroxide and carboxylate groups. Cluster 3 contains an oxidised derivative of the ligand, L(ox), generated in situ through hydroxylation of an α-carbon atom. This hexanuclear cluster has a 'barrel-like' core and contains Cu(II) ions in both square planar and square-based pyramidal geometries. Bridging between Cu(II) centres is furnished by alkoxide and carboxylate groups. Magnetic studies on 1-3 reveals dominant antiferro-magnetic interactions for 1 and 2, leading to small non-zero spin ground states, while 3 shows ferro-magnetic exchange between the Cu(II) centres to give an S = 3 spin ground state.

Carbonyl substitution chemistry of some trimetallic transition metal cluster complexes with polyfunctional ligands

The trimetallic clusters [Ru 3(CO) 10(dppm)], [Ru 3(CO) 12] and [RuCo 2(CO) 11] react with a number of multifunctional secondary phosphine and tertiary arsine ligands to give products consequent on carbonyl substitution and, in the case of the secondary phosphines, PH activation. The reaction with the unresolved mixed P/S donor, 1-phenylphosphino-2-thio(ethane), HSCH 2CH 2PHPh ( LH 2), gave two products under various conditions which have been characterised by spectroscopic and crystallographic means. These two complexes [Ru 3(μ-dppm)(H)(CO) 7(LH)] and [Ru 3(μ-dppm)(H)(CO) 8(LH)Ru 3(μ-dppm)(CO) 9], show the versatility of the ligand, with it chelating in the former and bridging two Ru 3 units in the latter. The stereogenic centres in the molecules gave rise to complicated spectroscopic data which are consistent with the presence of diastereoisomers. In the case of [Ru 3(CO) 12] the reaction with LH 2 gave a poor yield of a tetranuclear butterfly cluster, [Ru 4(CO) 10(L) 2], in which two of the ligands bridge opposite hinge wingtip bonds of the cluster. A related ligand, HSCH 2CH 2AsMe(C 6H 4CH 2OMe), reacted with [RuCo 2(CO) 11] to give a low yield of the heterobimetallic Ru–Co adduct, [RuCo(CO) 6(SCH 2CH 2AsMe(C 6H 4CH 2OMe))], which appears to be the only one of its type so far structurally characterised. The secondary phosphine, HPMe(C 6H 4(CH 2OMe)) and its oxide HP(O)Me(C 6H 4(CH 2OMe)) also react with the cluster [Ru 3(CO) 10(dppm)] to give carbonyl substitution products, [Ru 3(CO) 5(dppm)(μ 2-PMe(C 6H 4CH 2OMe)) 4], and [Ru 3H(CO) 7(dppm)(μ 2,η 1-P( O)Me(C 6H 4CH 2OMe))]. The former consists of an open Ru 3 triangle with four phosphide ligands bridging the metal–metal bonds; the latter has the O atom symmetrically bridging one Ru–Ru bond, the P atom being attached to a non-bridged Ru atom.

New Cyclosiloxanolate Cluster Complexes of Transition Metals

New cyclosiloxanolate transition metal cluster complex derivatives were prepared. PhSiO2K reacted with NiX2 (X2 = Cl2 or acac) to give K2{[η6−(PhSiO2)6]2[μ3−(OH)]2Ni4K4}, a mixed group 1–group 10 metal complex. PhSiO2Na reacted with Ni(NH3)6I2 to give Na{[η6−(PhSiO2)6]2Ni6(μ6−I)} as the first example of “encapsulated” I− ion in siloxanolate complexes. The macrocyclic Na4{[η12−(PhSiO2)12]Cu4} complex reacted with η6−(1,3,5−C7H8)Cr(CO)3 to give the heterobimetallic adduct Na4{[η12−(PhSiO2)12]Cu4}· [Cr(CO)3]3 as one of the rare examples of heterobimetallic complexes with different oxidation numbers of the metals. The copper derivative {[η6−(PhSiO2)6]2Cu6(n−BuOH)5} reacted in MeOH/CHCl3 (1:6) with Et4NCN to give the hexanuclear complex {[η6−(PhSiO2)6]2Cu6(η2−C3H5N2O2)2}, containing 2-amino-2-oxoetanimidic acid methyl ester monoanion ligands, product of an unexpected C–C coupling reaction. This latter complex was characterized also by X-ray diffraction crystal and molecular structure determination.

ChemInform Abstract: Concepts and Models for Characterizing Homogeneous Reactions Catalyzed by Transition Metal Cluster Complexes

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis, structures and reaction mechanism of transition metal cluster complexes η 5 -RC 5 H 4 (CO) 2 MCo 3 (CO) 6 ( μ -CO) 3

The tetrahedral metal-cluster complexes containing alkylcyclopentadienyl ligand η5-RC5H4(CO)2 MCo3(CO)6(μ-CO)3(M = Mo, W; R=CH3, C2H5, n-C4H9, C6H5CH2) have been synthesized by thermal reaction of metal-metal single-bonded compounds [η5-RC5H4(CO)3M]2 with Co2(CO)8, and characterized by elemental analysis, 1R, 1H NMR and MS spectroscopies. The thermal reaction mechanism is studied and a single-crystal molecular structure of η5-n-C4H9C5H4(CO)2MoCo3(CO)6(μ-CO)3 determined with the X-ray diffraction method. The molecule crystallizes in the space group P21/C with cell parameters a= 1.0088(2), b= 1.3063(3), c=1 8320(5) ran, β = 96.04(2)°; the final deviation factor R = 0.041.

A comparison of bismuth- and antimony-containing transition metal cluster complexes

In recent years a number of transition metal clusters which incorporate bismuth and antimony have been reported. The structures and reaction chemistry of these complexes are compared.

Electronic structures of transition metal cluster complexes

Electronic structures of transition metal cluster complexes

Synthesis of tetrahedral mixed-metal clusters of the iron triad. Preparation and characterization of tridecacarbonyldihydroironosmiumdiruthenium and tridecacarbonyldihydroirondiosmiumruthenium

Abstract : Transition metal cluster complexes have become a very important class of compounds, principally because of their potential in catalysis. Clusters have been shown to behave as catalysts in their own right and they hold considerable promise for serving as models for catalytic surfaces. Clusters comprised of two or more different transition metals in the cluster framework are particularly interesting in this regard because of possible bimetallic effects. Further, mixed-metal clusters have non-equivalent bonding sites. As such they are ideally suited for modeling studies which employ variable temperature NMR to follow the movements of substrates over their surfaces. One of the problems which has hampered studies of mixed-metal clusters is their relative lack of availability. Only a very few isostructural series have been achieved, and general synthetic methods for mixed-metal clusters are lacking. Carbonylmetalates have been widely used as synthetic reagents in cluster chemistry and several of the reported reactions appear to be adaptable to design. This is particularly true of the reactions of Knight and Mays who prepared a series of Group 7 - Group 8 tetrameric mixed-metal clusters through the addition of a carbonylmetalate to a closed M3(CO)12 trimer.

Transition metal cluster complexes as catalysts. A review

Transition metal cluster complexes as catalysts. A review

ChemInform Abstract: A NOVEL BONDING SCHEME OF AN ALLENE SYSTEM IN A TRANSITION METAL CLUSTER COMPLEX. MOLECULAR STRUCTURE OF μ3‐η‐(1‐METHYL‐3‐ETHYL‐3‐ALLENYL)‐μ‐HYDRIDO‐TRIANGULO‐TRIS(TRICARBONY# LRUTHENIUM)(3RU‐RU)

Chemischer InformationsdienstVolume 7, Issue 30 Physical Organic Chemistry ChemInform Abstract: A NOVEL BONDING SCHEME OF AN ALLENE SYSTEM IN A TRANSITION METAL CLUSTER COMPLEX. MOLECULAR STRUCTURE OF μ3-η-(1-METHYL-3-ETHYL-3-ALLENYL)-μ-HYDRIDO-TRIANGULO-TRIS(TRICARBONY# LRUTHENIUM)(3RU-RU) GIULIANA GERVASIO, GIULIANA GERVASIOSearch for more papers by this authorDOMENICO OSELLO, DOMENICO OSELLOSearch for more papers by this authorMARIO VALLE, MARIO VALLESearch for more papers by this author GIULIANA GERVASIO, GIULIANA GERVASIOSearch for more papers by this authorDOMENICO OSELLO, DOMENICO OSELLOSearch for more papers by this authorMARIO VALLE, MARIO VALLESearch for more papers by this author First published: July 27, 1976 https://doi.org/10.1002/chin.197630078AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume7, Issue30July 27, 1976 RelatedInformation

A novel bonding scheme of an allene system in a transition metal cluster complex. Molecular structure of .mu.3-.eta.-(1-methyl-3-ethyl-3-allenyl)-.mu.-hydrido-triangulo-tris(tricarbonylruthenium)(3Ru-Ru)

A novel bonding scheme of an allene system in a transition metal cluster complex. Molecular structure of .mu.3-.eta.-(1-methyl-3-ethyl-3-allenyl)-.mu.-hydrido-triangulo-tris(tricarbonylruthenium)(3Ru-Ru)

Magnetic exchange in transition metal complexes. VIII. Molecular field theory of intercluster interactions in transition metal cluster complexes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMagnetic exchange in transition metal complexes. VIII. Molecular field theory of intercluster interactions in transition metal cluster complexesA. P. Ginsberg and M. E. LinesCite this: Inorg. Chem. 1972, 11, 9, 2289–2290Publication Date (Print):September 1, 1972Publication History Published online1 May 2002Published inissue 1 September 1972https://doi.org/10.1021/ic50115a074RIGHTS & PERMISSIONSArticle Views280Altmetric-Citations105LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (275 KB) Get e-Alerts Get e-Alerts

Evidence for Large Antisymmetric Superexchange in Tetrameric Copper Complexes

Transition metal cluster complexes often combine high local symmetry about individual magnetic ions with low spin-pair symmetry. These complexes should therefore enrich greatly the field of study of highly anisotropic, particularly asymmetric, exchange phenomena of low order. We illustrate by presenting evidence indicating strongly that the tetrameric copper complex ${\mathrm{Cu}}_{4}$O${{\mathrm{Cl}}_{6}[{\mathrm{O}\mathrm{P}({\mathrm{C}}_{6}{\mathrm{H}}_{5})}_{3}]}_{4}$ provides the first example in the literature of large (lowest-order) antisymmetric superexchange between orbitally degenerate magnetic ions.

Organometallic chalcogen complexes. XXIII. Preparation and structural characterization of a mixed transition metal cluster complex, [Re2Mo(h5-C5H5)(CO)8](S)[SMo(h5-C5H5)(CO)3], containing triply and quadruply bridging sulfur atoms. New synthetic route to highly clustered metal-sulfur systems

Organometallic chalcogen complexes. XXIII. Preparation and structural characterization of a mixed transition metal cluster complex, [Re2Mo(h5-C5H5)(CO)8](S)[SMo(h5-C5H5)(CO)3], containing triply and quadruply bridging sulfur atoms. New synthetic route to highly clustered metal-sulfur systems