Samarium(III) Pentalene Sandwich Compounds [Sm(η8-C8H4{SiiPr3-1,4}2)(Cp*)] and [Sm(η8-C8H4{SiiPr3-1,4}2)(η5-C8H5{SiiPr3-1,4}2)] and a Mixed-Valence Hexasamarium Cluster Derived from Sm(II)-Based Solvent Activation

Summerscales, Owen T.; Johnston, David R.; Cloke, F. Geoffrey N.; Hitchcock, Peter B.

doi:10.1021/om701152k

Cited by 19 publications

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“…These sandwich structures have very similar geometries around the Fe centre, with metalcentroid distances and near linear centroidmetalcentroid angles which are consistent with ferrocene and its pentalene analogues that have been previously determined by X-ray diffraction studies. [20][21][22][23][24] Removal of an allylic proton from 1 to form 2 results in a formal negative charge on the five membered ring of the coordinated pentalene ligand, to which potassium coordinates in an This is consistent with a localised double bond, and similar values are found in previously reported hydropentalenyl compounds [27] (dC=C = 1.329(8), 1.377(9) and 1.354(7) Å respectively).…”

Section: Iron Bis(pentalene) Complexessupporting

confidence: 81%

Complexes of iron(II) with silylated pentalene ligands; building blocks for homo- and heterobimetallics

et al. 2016

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(2016) Complexes of Iron(II) with silylated pentalene ligands; building blocks for homo-and heterobimetallics. Polyhedron, This version is available from Sussex Research Online: http://sro.sussex.ac.uk/59846/ This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the URL above for details on accessing the published version. Copyright and reuse:Sussex Research Online is a digital repository of the research output of the University.Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available.Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. DFT calculations on model mono-Fe(η 5 -Pn) compounds reveal the charge densities on the uncoordinated carbon atoms of the pentalene ligand, and hence the potential for incorporating these units into heteronuclear bimetallic complexes is assessed.

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Section: Iron Bis(pentalene) Complexessupporting

confidence: 81%

Complexes of iron(II) with silylated pentalene ligands; building blocks for homo- and heterobimetallics

et al. 2016

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“…[K] 2 with [SmCp*(μ-I)(THF) 2 ] 2 , in which we obtained not the anticipated Sm(II) anti-bimetallic species, but oxidized products Sm(η 8 ), and a mixed-valence hexasamarium cluster obtained via solvent activation of THF. 55 The results described above show that identical reactions with Eu and Yb have allowed successful access to Ln(II)-pentalene anti-bimetallic systems (1 and 2). Additionally, use of COT 1,4-Si i Pr 3 [K] 2 in the Sm reaction gave no evidence of oxidation of the metal centers (or solvent activation) occurring and the anticipated Sm(II) (5) species was obtained.…”

Section: Resultsmentioning

confidence: 84%

“…We have recently reported the analogous reaction of C 8 H 4 1,4-Si i Pr 3 [K] 2 with [SmCp*(μ-I)(THF) 2 ] 2 , in which we obtained not the anticipated Sm(II) anti-bimetallic species, but oxidized products Sm(η 8 -C 8 H 4 1,4-Si i Pr 3 )(η 5 -Cp*), Sm(η 8 -C 8 H 4 1,4-Si i Pr 3 )(η 5 -C 8 H 5 1,4-Si i Pr 3 ), and a mixed-valence hexasamarium cluster obtained via solvent activation of THF . The results described above show that identical reactions with Eu and Yb have allowed successful access to Ln(II)−pentalene anti-bimetallic systems ( 1 and 2 ).…”

Section: Resultsmentioning

confidence: 86%

“…The rings are bent at an angle of 161°, slightly smaller than that found for the unsilylated compound Sm(COT)(Cp*) (164°). , The average Sm−C(Cp*) distance of 2.691(4) Å reflects the trivalent Sm center; the equivalent distances found in the Sm(II) complexes 5 and 6 are 2.847(9) and 2.781(4) Å, respectively. 7 is the cyclooctatetraene analogue of the known pentalene complex Sm(C 8 H 4 1,4-Si i Pr 3 )(Cp*) and the Sm(III) base-free analogue of the U(III) compound U(COT 1,4-Si i Pr 3 )(Cp*)(THF) (the base-free U(III) complex is also known but has not been structurally characterized) …”

Section: Resultsmentioning

confidence: 99%

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Anti-Bimetallic Complexes of Divalent Lanthanides with Silylated Pentalene and Cyclooctatetraenyl Bridging Ligands as Molecular Models for Lanthanide-Based Polymers

et al. 2009

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The new pentalene antibimetallic compounds [MCp*(THF)] 2 (μ,η 5 :η 5 -C 8 H 4 1,4-Si i Pr 3) were prepared for M = Eu (1), Yb (2) from the one-pot reaction of MI 2 (THF) x and KCp* and the subsequent addition of 1 / 2 equiv of C 8 H 4 1,4-Si i Pr 3[K] 2 in THF. The related series of COT 1,4-Si i Pr 3 -bridged triple-deckers [MCp*(THF) x ] 2 (μ,η 8 :η 8 -COT 1,4-Si i Pr 3 ) (M=Eu, x=0 (3); M=Yb, x=0 (4); M=Sm, x=1 (5)) were synthesized similarly; additionally, the base-free derivative with M=Sm and x=0 (6) could be prepared by reaction of [SmCp*(μ-I)(THF) 2 ] 2 with COT 1,4-Si i Pr 3 [K] 2 in toluene with heating. The solid-state structures, as determined by X-ray diffraction, show antibimetallic arrangements in which the divalent lanthanide centers are held on opposing sides of a planar bridging ligand. The pentalene ligand coordinates in an approximate η 5 :η 5 mode, with the metal centers slipped toward the wingtip carbons, whereas the COT ligand is bound in an η 8 :η 8 fashion with the metal centers aligned with the centroid of the bridging ligand. Electronic spectroscopy suggests the Eu and Yb pentalene complexes have a smaller f-d gap than their COT analogues, indicating a greater extent of through-ligand metal-metal interaction in the pentalene species. [EuCp*(THF) x ] 2 (μ-COT 1,4-Si i Pr 3 ) displays a weak green-yellow emission in THF solution (λ max 509 nm, Φ em < 0.1%) upon excitation in the UV, consistent with a 4f 6 5d 1 f 4f 7 emission process, with a short lifetime indicative of Eu-Eu coupling through the bridging COT ligand. Cyclic voltammetry reveals that 1, 3, and 4 decompose rapidly upon oxidation, although the monocation 2 þ appears to be stable in THF solution. Through-ligand Yb-Yb coupling is suggested by the electrochemical data for 2, of magnitude similar to that observed for its transition-metal analogues. However, unfortunately, attempts to further quantify this conclusion by spectroscopic investigation of 2 þ were unsuccessful.

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“…This is found to occur for complexes in which bonding interactions are significantly increased, as folding of the carbocyclic framework results in distortion of the π-system and a loss of aromaticity. This binding mode is therefore generally seen with relatively large metal centers: found for early transition metals and f-elements. − When coordinated in this manner, a series of group 4 “pentalene bent metallocenes” can be envisaged whereby the two Cp rings are replaced with a single pentalene ligand. Using the Green et al electron counting system, this results in reduction of the formal electron count of the metal complex by 2; Pn* possesses eight electrons compared to 10 for two Cp ligands (Figure ) .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Group 4 Permethylpentalene Dichloride Complexes

et al. 2013

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We report the high-yield syntheses of the (η8-Pn*)MCl2 complexes (η8-Pn* = C8Me6; M = Ti, Zr, Hf), utilizing the cis-(SnMe3)2Pn* or cis-Li2Pn*(TMEDA) x synthons. Stereoselective synthesis of the appropriate Pn* precursor [cis-Li2Pn* and cis-(SnMe3)2Pn*] can be achieved by the appropriate choice of solvent. Treatment of cis-(SnMe3)2Pn* with TiCl4·2THF enabled the first high-yielding synthesis of a group 4 η8-Pn* complex, [η8-Pn*TiCl(μ-Cl)]2 (1). Analogous complexes for the remaining group 4 congeners have been synthesized via the reaction of Li2Pn*(TMEDA) x with MCl4·2THF (M = Zr, Hf). These have been found to incorporate LiCl, resulting in the chemical formula [η8-Pn*M(μ-Cl)3/2]2(μ-Cl)2Li·THF x [M = Zr (2), Hf (3)]. 1, 2, and 3 have all been fully characterized in the solution phase and in the solid state via single-crystal X-ray diffraction, revealing all three to be dimeric; 3 is the first structurally elucidated hafnium pentalene compound. The solid-state structure of trans-(SnMe3)2Pn* has also been reported. All three compounds have been produced in sufficiently high yields to act as excellent entry points to further group 4 η8-Pn* species via salt metathesis reactions.

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Samarium(III) Pentalene Sandwich Compounds [Sm(η⁸-C₈H₄{SiⁱPr₃-1,4}₂)(Cp*)] and [Sm(η⁸-C₈H₄{SiⁱPr₃-1,4}₂)(η⁵-C₈H₅{SiⁱPr₃-1,4}₂)] and a Mixed-Valence Hexasamarium Cluster Derived from Sm(II)-Based Solvent Activation

Cited by 19 publications

References 35 publications

Complexes of iron(II) with silylated pentalene ligands; building blocks for homo- and heterobimetallics

Complexes of iron(II) with silylated pentalene ligands; building blocks for homo- and heterobimetallics

Anti-Bimetallic Complexes of Divalent Lanthanides with Silylated Pentalene and Cyclooctatetraenyl Bridging Ligands as Molecular Models for Lanthanide-Based Polymers

Synthesis and Characterization of Group 4 Permethylpentalene Dichloride Complexes

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