Dinuclear Metal Center Research Articles

Reactions of [Fe 2(CO) 6(μ-CO)(μ-dppm)] with alkynes: Stepwise synthesis of tropone at a dinuclear metal centre

The di-iron complex [Fe 2(CO) 6(μ-CO)(μ-dppm)] [ 1; dppm = bis(diphenylphosphino)methane] reacts with alkynes R 1CCR 2 under UV irradiation to produce dimetallacyclopentenone complexes [Fe 2(CO) 5{ μ- σ: η 3-CR 1CR 2C(O)}( μ-dppm)] ( 2a-e; R 1 = R 2 = H, Me or Ph; R 1 = H, R 2 = Me or Ph). The complexes exist in two isomeric forms in which the diphosphine ligand is either cis or trans with respect to the organic ligand. In the cis isomers of complexes 2 the R 1 site is occupied by hydrogen, while in the trans isomers the R 1 site is occupied by Me or Ph, suggesting that steric factors control the geometry. The molecular structure of cis-[Fe 2(CO) 5{ μ- σ: η 3-CHCHC(O)}( μ-dppm)] ( 2a) has been elucidated by X-ray diffraction. The complex exists in the solid state as a mixture of enantiomers, shown by variable temperature NMR spectroscopy to interconvert in solution via ethyne migration from one CO ligand to another. Further reaction of 2a with ethyne affords [Fe 2(CO) 4{ μ- σ, σ′: η 2, η 2′-CHCHC(O)CHCH}( μ-dppm)] ( 3) and [Fe 2(CO) 4{ μ- η 3: η 3′-C 6H 6C(O)}( μ-dppm)] ( 4) stepwise, containing and three molecules of ethyne, respectively. X-ray diffraction studies show that 3 is a pentadienone “fly-over bridge” complex and that 4 is a complex of tropone, stabilized by a weak intramolecular CH…O hydrogen bond. Addition of diphenylacetylene to trans-[Fe 2(CO) 5{ μ- σ: η 3-CPhCPhC(O)}( μ-dppm)] ( 2e) affords the “ferrole” complex trans-[Fe 2(CO) 5{ μ- σ, σ′: η 4-C 4Ph 4}( μ-dppm)] ( 5), also crystallographically characterized. The different pathways for alkyne linking with 2a and 2e are traced to steric factors, arising from the different orientations of the diphosphine and organic ligands in the two species.

Structure and function of dinuclear metal centres in proteins: optical and magnetic studies

Structure and function of dinuclear metal centres in proteins: optical and magnetic studies

Sequence homology between purple acid phosphatases and phosphoprotein phosphatases: Are phosphoprotein phosphatases metalloproteins containing oxide-bridged dinuclear metal centers?

The amino acid sequences of mammalian purple acid phosphatases and phosphoprotein phosphatases are shown to possess regions of significant homology. The conserved residues contain a high percentage of possible metal-binding residues. The phosphoprotein phosphatases 1, 2A and 2B are proposed to be iron-zinc metalloenzymes with active sites isostructural (or nearly so) with those of the purple phosphatases.

Organic chemistry of dinuclear metal centres. Part 14. Synthesis, X-Ray structure, and reactivity of the ruthenium–ruthenium double-bonded complex [Ru2(μ-CO)(μ-C2Ph2)(η-C5H5)2

Ultraviolet irradiation of the metallacycle [Ru2(CO)(μ-CO){μ-C(O)C2Ph2}(η-C5H5)2] (1) in tetrahydrofuran (thf) gives the complex [Ru2(μ-CO)(μ-C2Ph2)(η-C5H5)2] (2), shown by X-ray diffraction to have a ruthenium–ruthenium double bond [RuRu 2.505(1) A] bridged transversely by a diphenylacetylene ligand. The loss of two molecules of CO in forming (2) is reversible; under 100 atm of CO at 50 °C complex (2) is converted into (1) in 60% yield. Treatment of unsaturated complex (2) with diazoalkanes RCHN2 (R = H, Me, or CO2Et) results in the corresponding uptake of two alkylidene units to form [Ru2(CO)(μ-CHR){η-C(Ph)C(Ph)CHR}(η-C5H5)2], existing as isomers for R = Me or CO2Et due to differing orientations of the μ-CHR substituent. The structure of [Ru2(CO)(μ-CH2){μ-C(Ph)C(Ph)CH2}(η-C5H5)2] (3) has been established by X-ray diffraction, revealing that one methylene co-ordinates to the dinuclear metal centre while the other links with the alkyne. There are non-bonding C–C distances of 3.07 A between the two μ-carbons of the complex, but only 2.78 A separating the μ-CH2 carbon and the CH2 carbon of the C(Ph)C(Ph)CH2 ligand. On thermolysis the latter two carbons link, accompanied by other processes, to afford [Ru2(CO)(μ-CO){μ-C(Ph)C(Ph)CHMe}(η-C5H5)2] (5). A co-product of the reaction of diazoethane with (2) is the di-μ-vinyl complex [Ru2(CO) (μ-CHCH2){μ-C(Ph)CHPh}(η-C5H5)2] (8). X-ray diffraction reveals that the two β-carbons of the vinyl groups are 2.99 A apart and it is these rather than the two μ(α) carbons (3.06 A apart) which link on thermolysis, affording complex (5) once more. Thermolysis of [Ru2(CO)(μ-CHCO2Et){μ-C(Ph)C(Ph)CH(CO2Et)}(η-C5H5)2] does not effect carbon–carbon bond formation. Instead, CO is ejected and its site occupied by an oxygen of a carboethoxy group in the complex [Ru2(μ-CHCO2Et){μ-C(Ph)C(Ph)CHC(O)OEt}(η-C5H5)2]. Treatment of complex (1) with BH3·thf or LiMe–HBF4–NaBH4 converts the metallacyclic ketone group into CH2 or CHMe respectively, yielding [Ru2(CO)(μ-CO){μ-C(Ph)C(Ph)CHR}(η-C5H5)2] (R = H or Me). The nature of the processes observed on thermolysis of complexes (3) and (8) suggests the importance of least-motion effects in determining the course of carbon–carbon bond formation at a dinuclear metal centre.

Molecular A-frames. Reversible addition of diazoalkanes to dinuclear metal centers and the formation of [Rh2(.mu.-N2CRCO2Et)(CO)2(dppm)2] (R = H, CO2Et)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular A-frames. Reversible addition of diazoalkanes to dinuclear metal centers and the formation of [Rh2(.mu.-N2CRCO2Et)(CO)2(dppm)2] (R = H, CO2Et)Carrie Woodcock and Richard EisenbergCite this: Organometallics 1985, 4, 1, 4–7Publication Date (Print):January 1, 1985Publication History Published online1 May 2002Published inissue 1 January 1985https://doi.org/10.1021/om00120a002RIGHTS & PERMISSIONSArticle Views75Altmetric-Citations27LEARN 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 (457 KB) Get e-Alerts Get e-Alerts

ChemInform Abstract: ORGANIC CHEMISTRY OF DINUCLEAR METAL CENTERS. PART 1. COMBINATION OF ALKYNES WITH CARBON MONOXIDE AT DIIRON AND DIRUTHENIUM CENTERS: CRYSTAL STRUCTURE OF μ‐CARBONYL‐1‐CARBONYL‐1,2‐BIS(η‐CYCLOPENTADIENYL)‐μ‐(Σ:1′‐3′‐.E# TA.‐3′‐OXO‐1′,2′‐DIPHENYLPROPEN‐1′,3′‐DIYL)DIRUTHENIUM(RU‐RU)

Chemischer InformationsdienstVolume 13, Issue 42 Organoelement Compounds ChemInform Abstract: ORGANIC CHEMISTRY OF DINUCLEAR METAL CENTERS. PART 1. COMBINATION OF ALKYNES WITH CARBON MONOXIDE AT DIIRON AND DIRUTHENIUM CENTERS: CRYSTAL STRUCTURE OF μ-CARBONYL-1-CARBONYL-1,2-BIS(η-CYCLOPENTADIENYL)-μ-(Σ:1′-3′-.E# TA.-3′-OXO-1′,2′-DIPHENYLPROPEN-1′,3′-DIYL)DIRUTHENIUM(RU-RU) A. F. DYKE, A. F. DYKESearch for more papers by this authorS. A. R. KNOX, S. A. R. KNOXSearch for more papers by this authorP. J. NAISH, P. J. NAISHSearch for more papers by this authorG. E. TAYLOR, G. E. TAYLORSearch for more papers by this author A. F. DYKE, A. F. DYKESearch for more papers by this authorS. A. R. KNOX, S. A. R. KNOXSearch for more papers by this authorP. J. NAISH, P. J. NAISHSearch for more papers by this authorG. E. TAYLOR, G. E. TAYLORSearch for more papers by this author First published: October 19, 1982 https://doi.org/10.1002/chin.198242319AboutPDF 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 onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume13, Issue42October 19, 1982 RelatedInformation