Kyle Pearce

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06 Dec 08:56

[ASAP] Al–Sc Bonded Complexes: Synthesis, Structure, and Reaction with Benzene in the Presence of Alkyl Halide

by Genfeng Feng, Ka Lok Chan, Zhenyang Lin, and Makoto Yamashita

TOC Graphic

Journal of the American Chemical Society
DOI: 10.1021/jacs.2c09746
27 Nov 13:52

Alkaline‐Earth Metal Mediated Benzene‐to‐Biphenyl Coupling

by Jonathan Mai, Michael Morasch, Dawid Jędrzkiewicz, Jens Langer, Bastian Rösch, Sjoerd Harder
Alkaline-Earth Metal Mediated Benzene-to-Biphenyl Coupling

Attempts to isolate low-valent (BDI)Ae-Ae(BDI) complexes led to reduction of the benzene solvent and formation of (BDI)Ae-(C6H6)-Ae(BDI); BDI=β-diketiminate ligand, Ae=Ca or Sr. Reaction of bridging C6H6 2− with benzene gave (biphenyl)2− complexes. Ball-milling is an efficient synthetic tool for this dehydrogenative benzene-benzene coupling. Calculations suggest attack of C6H6 2− at benzene. This is facilitated by Ae2+⋅⋅⋅benzene coordination.


Abstract

Complex [(DIPePBDI)Ca]2(C6H6), with a C6H6 2− dianion bridging two Ca2+ ions, reacts with benzene to yield [(DIPePBDI)Ca]2(biphenyl) with a bridging biphenyl2− dianion (DIPePBDI=HC[C(Me)N-DIPeP]2; DIPeP=2,6-CH(Et)2-phenyl). The biphenyl complex was also prepared by reacting [(DIPePBDI)Ca]2(C6H6) with biphenyl or by reduction of [(DIPePBDI)CaI]2 with KC8 in presence of biphenyl. Benzene-benzene coupling was also observed when the deep purple product of ball-milling [(DIPPBDI)CaI(THF)]2 with K/KI was extracted with benzene (DIPP=2,6-CH(Me)2-phenyl) giving crystalline [(DIPPBDI)Ca(THF)]2(biphenyl) (52 % yield). Reduction of [(DIPePBDI)SrI]2 with KC8 gave highly labile [(DIPePBDI)Sr]2(C6H6) as a black powder (61 % yield) which reacts rapidly and selectively with benzene to [(DIPePBDI)Sr]2(biphenyl). DFT calculations show that the most likely route for biphenyl formation is a pathway in which the C6H6 2− dianion attacks neutral benzene. This is facilitated by metal-benzene coordination.

24 Nov 09:01

[ASAP] Synthesis, Characterization, and Structural Analysis of AM[Al(NONDipp)(H)(SiH2Ph)] (AM = Li, Na, K, Rb, Cs) Compounds, Made Via Oxidative Addition of Phenylsilane to Alkali Metal Aluminyls

by Gerd M. Ballmann, Matthew J. Evans, Thomas X. Gentner, Alan R. Kennedy, J. Robin Fulton, Martyn P. Coles, and Robert E. Mulvey

TOC Graphic

Inorganic Chemistry
DOI: 10.1021/acs.inorgchem.2c03010
18 Nov 08:59

Reduction of Na+ within a {Mg2Na2} Assembly

by Han-Ying Liu, Samuel E. Neale, Michael Stephen Hill, Mary F. Mahon, Claire L McMullin, Emma Richards
Reduction of Na+ within a {Mg2Na2} Assembly

Treatment of a low oxidation state {Mg2Na2} assembly with basic molecules that are less prone to reduction than the sodium cation itself induces the complete extrusion of the elemental alkali metal.


Abstract

Ionic compounds containing sodium cations are notable for their stability and resistance to redox reactivity unless highly reducing electrical potentials are applied. Here we report that treatment of a low oxidation state {Mg2Na2} species with non-reducible organic bases induces the spontaneous and completely selective extrusion of sodium metal and oxidation of the MgI centers to the more conventional MgII state. Although these processes are also characterized by a structural reorganisation of the initially chelated diamide spectator ligand, computational quantum chemical studies indicate that intramolecular electron transfer is abetted by the frontier molecular orbitals (HOMO/LUMO) of the {Mg2Na2} ensemble, which arise exclusively from the 3s valence atomic orbitals of the constituent sodium and magnesium atoms.

08 Nov 13:53

Anionic Magnesium and Calcium Hydrides: Transforming CO into Unsaturated Disilyl Ethers

by Jacob S. McMullen, Ryan Huo, Petra Vasko, Alison J. Edwards, Jamie Hicks
Anionic Magnesium and Calcium Hydrides: Transforming CO into Unsaturated Disilyl Ethers

CO has directly been transformed into small organic starting materials using earth-abundant, anionic group 2 hydride reagents.


Abstract

The synthesis, characterisation and reactivity of two isostructural anionic magnesium and calcium complexes is reported. By X-ray and neutron diffraction techniques, the anionic hydrides are shown to exist as dimers, held together by a range of interactions between the two anions and two bridging potassium cations. Unlike the vast proportion of previously reported dimeric group 2 hydrides, which have hydrides that bridge two group 2 centres, here the hydrides are shown to be “terminal”, but stabilised by interactions with the potassium cations. Both anionic hydrides were found to insert and couple CO under mild reaction conditions to give the corresponding group 2 cis-ethenediolate complexes. These cis-ethenediolate complexes were found to undergo salt elimination reactions with silyl chlorides, allowing access to small unsaturated disilyl ethers with a high percentage of their mass originating from the C1 source CO.

04 Nov 08:52

Triple dehydrofluorination as a route to amidine-functionalized, aromatic phosphorus heterocycles

Chem. Commun., 2022, 58,13580-13583
DOI: 10.1039/D2CC05178H, Communication
Open Access Open Access
Nathan T. Coles, Lucie J. Groth, Lea Dettling, Daniel S. Frost, Massimo Rigo, Samuel E. Neale, Christian Müller
Hitherto unknown amidine-functionalized phosphabenzenes selectively form by a cascade of dehydrofluorination reactions.
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31 Oct 10:56

[ASAP] Perdeuteration of Arenes via Hydrogen Isotope Exchange Catalyzed by the Superbasic Sodium Amide Donor Species NaTMP·PMDETA

by Andreu Tortajada and Eva Hevia

TOC Graphic

Journal of the American Chemical Society
DOI: 10.1021/jacs.2c09778
08 Apr 08:05

(PNSiMe3)4(NMe)6: A Robust Tetravalent Phosphaza‐adamantane Scaffold for Molecular and Macromolecular Construction

by Joseph Bedard, Nicholas Roberts, Mohsen Shayan, Karlee L Bamford, Ulrike Werner-Zwanziger, Katherine M. Marczenko, Saurabh S. Chitnis
(PNSiMe3)4(NMe)6: A Robust Tetravalent Phosphaza-adamantane Scaffold for Molecular and Macromolecular Construction**

The synthesis of a new air-stable and thermally robust tetrahedral tetravalent inorganic cage, (PNSiMe3)4(NMe)6 has been achieved. This cage allows four-fold functionalization reactions on its periphery to give unprecedented molecular and macromolecular constructs. This utility is shown by the synthesis of a tetrakis(bis(phosphine)iminium) ion and the first all P/N polyphazene network material.


Abstract

Tetraarylmethanes and adamantanes are important rigid covalent connectors that play a four-way scaffolding role in molecular and materials chemistry. We report the synthesis of a new tetravalent phosphaza-adamantane cage, (PNSiMe3)4(NMe)6 (2), that shows high thermal, air, and redox stability due to its geometry. It nevertheless participates in covalent four-fold functionalization reactions along its periphery. The combination of a robust core and reactive corona makes 2 a convenient inorganic scaffold upon which tetrahedral molecular and macromolecular chemistry can be constructed. This potential is demonstrated by the synthesis of a tetrakis(bis(phosphine)iminium) ion (in compound 3) and the first all P/N poly(phosphazene) network (5).

28 Mar 07:56

A Terphenyl Supported Dioxophosphorane Dimer: the Light Congener of Lawesson's and Woollins’ Reagents

by Laura E English, Aleksandra Pajak, Claire L McMullin, John P Lowe, Mary F Mahon, David Liptrot
A Terphenyl Supported Dioxophosphorane Dimer: the Light Congener of Lawesson's and Woollins’ Reagents

Pyridines have been shown to mediate the release of ethene from a terphenyl supported 1,3-dioxo-2-phospholane. This generates a dioxophosphorane dimer which is an oxygen analogue of Lawesson's and Woollins’ reagents. This compound was structurally characterised and its solution behaviour interrogated. Insight into the ethene release reaction is provided by the isolation of a DMAP-coordinated dioxophosphorane


Abstract

Thermolysis of a 1,3-dioxa-2-phospholane supported by the terphenyl ligand AriPr4 (AriPr4=[C6H3-2,6-(C6H3-2,6-iPr2)]) at 150 °C gives [AriPr4PO2]2 via loss of ethene. [AriPr4PO2]2 was characterised by X-ray crystallography and NMR spectroscopy; it contains a 4-membered P−O−P−O ring and is the isostructural oxygen analogue of Lawesson's and Woollins’ reagents. The dimeric structure of [AriPr4PO2]2 was found to persist in solution through VT NMR spectroscopy and DOSY, supported by DFT calculations. The addition of DMAP to the 1,3-dioxa-2-phospholane facilitates the loss of ethene to give AriPr4(DMAP)PO2 after days at room temperature, with this product also characterised by X-ray crystallography and NMR spectroscopy. Replacement of the DMAP with pyridine induces ethene loss from the 1,3-dioxa-2-phospholane to provide gram-scale samples of [AriPr4PO2]2 in 75 % yield in 2 days at only 100 °C.

25 Feb 11:01

Synthesis of Molecular Phenylcalcium Derivatives: Application to the Formation of Biaryls

by Michael Stephen Hill, Kyle G Pearce, Chiara Dinoi, Mary F Mahon, Laurent Maron, Ryan S Schwamm, Andrew S S Wilson
Synthesis of Molecular Phenylcalcium Derivatives: Application to the Formation of Biaryls

Isolable and hydrocarbon-soluble β-diketiminato calcium phenyls are accessible from the reaction of Ph2Hg and [(BDI)CaH]2. The compounds were shown to react with bromoarenes through a direct SNAr displacement of halide, leading to the uncatalyzed formation of biaryl molecules.


Abstract

Hydrocarbon-soluble β-diketiminato phenylcalcium derivatives, which display various modes of Ca−μ2-Ph−Ca bridging, are accessible from reactions of Ph2Hg and [(BDI)CaH]2. Although the resultant compounds are inert toward the C−H bonds of benzene, they yield selective and uncatalyzed biaryl formation when reacted with readily available aryl bromides.

16 Feb 08:51

On the reactivity of Al-group 11 (Cu, Ag, Au) bonds

Dalton Trans., 2022, 51,3913-3924
DOI: 10.1039/D2DT00404F, Paper
Han-Ying Liu, Samuel E. Neale, Michael S. Hill, Mary F. Mahon, Claire L. McMullin
Reactions of the seven-membered cyclic potassium diamidoalumanyl, [K{Al(SiNDipp)}]2 (SiNDipp = {CH2SiMe2NDipp}2; Dipp = 2,6-di-isopropylphenyl), with a variety of Cu(I), Ag(I) and Au(I) chloride N-heterocyclic carbene (NHC) adducts are described.
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03 Feb 10:16

Access to a Labile Monomeric Magnesium Radical by Ball‐Milling

by Dawid Jędrzkiewicz, Jonathan Mai, Jens Langer, Zachary Mathe, Neha Patel, Serena DeBeer, Sjoerd Harder
Access to a Labile Monomeric Magnesium Radical by Ball-Milling

Ball-milling of a magnesium iodide precursor with K/KI gave a mononuclear Mg radical which is stabilized by a CAAC ligand. Although stable in the crystalline state, the complex decomposed rapidly in solution. According to calculations and EPR spectroscopy, most of the spin density is localized on the CAAC ligand.


Abstract

In order to isolate a monometallic Mg radical, the precursor (Am)MgI⋅(CAAC) (1) was prepared (Am=tBuC(N-DIPP)2, DIPP=2,6-diisopropylphenyl, CAAC=cyclic (alkyl)(amino)carbene). Reduction of a solution of 1 in toluene with the reducing agent K/KI led to formation of a deep purple complex that rapidly decomposed. Ball-milling of 1 with K/KI gave the low-valent MgI complex (Am)Mg⋅(CAAC) (2) which after rapid extraction with pentane and crystallization was isolated in 15 % yield. Although a benzene solution of 2 decomposes rapidly to give Mg(Am)2 (3) and unidentified products, the radical is stable in the solid state. Its crystal structure shows planar trigonal coordination at Mg. The extremely short Mg−C distance of 2.056(2) Å indicates strong Mg−CAAC bonding. Calculations and EPR measurements show that most of the spin density is in a π* orbital located at the C−N bond in CAAC, leading to significant C−N bond elongation. This is supported by calculated NPA charges in 2: Mg +1.73, CAAC −0.82. Similar metal-to-CAAC charge transfer was calculated for M0(CAAC)2 and [MI(CAAC)2 +] (M=Be, Mg, Ca) complexes in which the metal charges range from +1.50 to +1.70. Although the spin density of the radical is mainly located at the CAAC ligand, complex 2 reacts as a low-valent MgI complex: reaction with a I2 solution in toluene gave (Am)MgI⋅(CAAC) (1) as the major product.

20 Jan 15:49

[ASAP] Facile Synthesis of the Dicyanophosphide Anion via Electrochemical Activation of White Phosphorus: An Avenue to Organophosphorus Compounds

by Yanbo Mei, Zeen Yan, and Liu Leo Liu

TOC Graphic

Journal of the American Chemical Society
DOI: 10.1021/jacs.1c11087
22 Dec 13:51

The structures of ring-expanded NHC supported copper(I) triphenylstannyls and their phenyl transfer reactivity towards heterocumulenes

Dalton Trans., 2022, 51,831-835
DOI: 10.1039/D1DT03109K, Communication
Open Access Open Access
Rex S. C. Charman, Mary F. Mahon, John P. Lowe, David J. Liptrot
A copper(I) stannyl supported by a ring-expanded N-heterocyclic carbene has been synthesised and its reactivity towards heterocumulenes has been investigated.
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29 Nov 13:02

Isocyanate deoxygenation by a molecular magnesium silanide

Dalton Trans., 2021, Advance Article
DOI: 10.1039/D1DT03775G, Paper
Open Access Open Access
Creative Commons Licence&nbsp This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Bibian Okokhere-Edeghoghon, Samuel E. Neale, Michael S. Hill, Mary F. Mahon, Claire L. McMullin
A molecular magnesium silanide is shown through a combined synthetic and computational study to effect siloxide formation and isocyanate deoxgenation via the initial formation of magnesium silamidate intermediates.
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23 Nov 20:22

A short, versatile route towards benzothiadiazinyl radicals

Chem. Sci., 2021, Advance Article
DOI: 10.1039/D1SC04248C, Edge Article
Open Access Open Access
Andryj M. Borys, Ewan R. Clark, Paul J. Saines, Antonio Alberola, Jeremy M. Rawson
A family of 1,2,4-benzothiadiazinyl radicals are accessible from 1,2,4-benzothiadiazine 1-chlorides which can be prepared in a single step by treatment of N-arylamidines in neat thionyl chloride at reflux.
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18 Oct 09:50

[ASAP] Reductive Dimerization of CO by a Na/Mg(I) Diamide

by Han-Ying Liu, Ryan J. Schwamm, Samuel E. Neale, Michael S. Hill, Claire L. McMullin, and Mary F. Mahon

TOC Graphic

Journal of the American Chemical Society
DOI: 10.1021/jacs.1c09467
30 Sep 10:03

A Benzodiphosphaborolediide

by Kyle G. Pearce, Elinor P. F. Canham, John F. Nixon, Ian R. Crossley
A Benzodiphosphaborolediide

The 1,3-diphosphaborolediide ligand motif, a hitherto missing member of the “hetero-Cp“ family, is obtained within an indenyl scaffold as its dilithium salt, as both thf and TMEDA solvates. This dianionic ligand exhibits aromaticity commensurate with its hybrid phospholide-borolediide nature, as is determined by NICS calculations and observed experimentally for both lithium salts. Additionally, coordination to zero-valent molybdenum is achieved, demonstrating a capacity to to coordinate readily as a π- and bridging π-,σ-type ligand.


Abstract

The first example of a diphosphaborolediide, the benzo-fused [C6H4P2BPh]2− (12− ), is prepared from ortho-bis(phosphino)benzene (C6H4{PH2}) and dichlorophenylborane, via a sequential lithiation approach. The dilithio-salt can be obtained as an oligomeric THF solvate or discrete TMEDA adduct, both of which are fully characterized, including by X-ray diffraction. Alongside NICS calculations, data strongly suggest some aromaticity within 12− , which is further supported by preliminary coordination studies that demonstrate η5-coordination to a zerovalent molybdenum center, as observed crystallographically for the oligomeric [{Mo(CO)3(η5-1)}{μ-η1-Mo(CO)3(TMEDA)}2] ⋅ [μ-Li(THF)][μ-Li(TMEDA)].

02 Sep 08:05

The Anionic Pathway in the Nickel‐Catalysed Cross‐Coupling of Aryl Ethers

by Andryj Borys, Eva Hevia
The Anionic Pathway in the Nickel-Catalysed Cross-Coupling of Aryl Ethers

Assessment of the rich co-complexation chemistry of Ni(COD)2 and PhLi has led to a new family of structurally diverse lithium nickelates being uncovered. Combined stoichiometric, catalytic, and kinetic studies reveal that these hetero-bimetallic complexes may be the key intermediates that facilitate the smooth C−O bond cleavage and cross-coupling of aryl ethers under mild conditions.


Abstract

The Ni-catalysed cross-coupling of aryl ethers is a powerful method to forge new C−C and C−heteroatom bonds. However, the inert C(sp2)−O bond means that a canonical mechanism that relies on the oxidative addition of the aryl ether to a Ni0 centre is thermodynamically and kinetically unfavourable, which suggests that alternative mechanisms may be involved. Here, we provide spectroscopic and structural insights into the anionic pathway, which relies on the formation of electron-rich hetero-bimetallic nickelates by adding organometallic nucleophiles to a Ni0 centre. Assessing the rich co-complexation chemistry between Ni(COD)2 and PhLi has led to the structures and solution-state chemistry of a diverse family of catalytically competent lithium nickelates being unveiled. In addition, we demonstrate dramatic solvent and donor effects, which suggest that the cooperative activation of the aryl ether substrate by Ni0-ate complexes plays a key role in the catalytic cycle.

27 Aug 09:08

[ASAP] The Phospha-Bora-Wittig Reaction

by Andryj M. Borys, Ella F. Rice, Gary S. Nichol, and Michael J. Cowley

TOC Graphic

Journal of the American Chemical Society
DOI: 10.1021/jacs.1c06228
01 Jul 08:15

[ASAP] A Cyaphide Transfer Reagent

by Daniel W. N. Wilson, Stephanie J. Urwin, Eric S. Yang, and Jose M. Goicoechea

TOC Graphic

Journal of the American Chemical Society
DOI: 10.1021/jacs.1c04417
15 Jun 08:44

C–H and C–F coordination of arenes in neutral alkaline earth metal complexes

Dalton Trans., 2021, 50,8685-8689
DOI: 10.1039/D1DT01532J, Communication
Jacob S. McMullen, Alison J. Edwards, Jamie Hicks
A series of neutral magnesium and calcium complexes that display various novel group 2⋯arene interaction have been synthesised and structurally characterised.
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04 May 12:42

Ambiphilic Al−Cu Bonding

by Michael Stephen Hill, Han-Ying Liu, Ryan Schwamm, Claire McMullin, Mary Mahon, Nasir Rajabi
Ambiphilic Al−Cu Bonding

Cu(ts) both ways: Carbene-supported copper-alumanyl complexes, [LCu-Al(SiNDipp)], display divergent reactivity with carbodiimides and CO2, implying an ambiphilicity in the Cu–Al interaction that is dependent on the identity of the carbene co-ligand.


Abstract

Copper-alumanyl complexes, [LCu-Al(SiNDipp)], where L=carbene=NHCiPr (N,N′-diisopropyl-4,5-dimethyl-2-ylidene) and Me2CAAC (1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene) and featuring unsupported Al−Cu bonds, have been prepared. Divergent reactivity observed with carbodiimides and CO2 implies an ambiphilicity in the Cu–Al interaction that is dependent on the identity of the carbene co-ligand.

04 May 12:33

Adducts of the Parent Boraphosphaketene H2BPCO and their Decarbonylative Insertion Chemistry

by Stephan Hagspiel, Felipe Fantuzzi, Rian D. Dewhurst, Annalena Gärtner, Felix Lindl, Anna Lamprecht, Holger Braunschweig
Adducts of the Parent Boraphosphaketene H2BPCO and their Decarbonylative Insertion Chemistry

The first examples of Lewis base adducts of the parent boraphosphaketene (H2B−PCO) are prepared, and their dimerization, decarbonylation and use as synthons for phosphinidenes is explored, leading to a number of different B/P-containing heterocycles and transition-metal complexes thereof.


Abstract

The first examples of Lewis base adducts of the parent boraphosphaketene (H2B-PCO) and their cyclodimers are prepared. One of these adducts is shown to undergo mild decarbonylation and phosphinidene insertion into a B−C bond of a borole, forming very rare examples of 1,2-phosphaborinines, B/P isosteres of benzene. The strong donor properties of these 1,2-phosphaborinines are confirmed by the synthesis of their π complexes with the Group 6 metals.

19 Jan 13:52

[ASAP] Beyond Ni{N(SiMe3)2}2: Synthesis of a Stable Solvated Sodium Tris-Amido Nickelate

by Andryj M. Borys and Eva Hevia

TOC Graphic

Organometallics
DOI: 10.1021/acs.organomet.0c00785
28 Oct 16:07

Spin‐Crossover Properties of an Iron(II) Coordination Nanohoop

by Maria Heras-Ojea, Jeff van Raden, Shayan Louie, Richard Collins, Daniel Pividori, Jordi Cirera, Karsten Meyer, Ramesh Jasti, Richard Layfield
Spin‐Crossover Properties of an Iron(II) Coordination Nanohoop

Addition of a bipyridyl embedded cycloparaphenylene (CPP) nanohoop to [Fe{H2B(pyz)2}] (pyz=pyrazolyl) produces the distorted octahedral complex [Fe(bipy[9]CPP){H2B(pyz)2}2]. Its spin‐crossover (SCO) properties are strongly influenced by a distortion associated with the nanohoop, implying that variations in nanohoop size may provide a way of tuning the SCO properties of iron compounds.


Abstract

Addition of the bipyridyl‐embedded cycloparaphenylene nanohoop bipy[9]CPP to [Fe{H2B(pyz)2}] (pyz=pyrazolyl) produces the distorted octahedral complex [Fe(bipy[9]CPP){H2B(pyz)2}2] (1). The molecular structure of 1 shows that the nanohoop ligand contains a non‐planar bipy unit. Magnetic susceptibility measurements indicate spin‐crossover (SCO) behaviour with a T 1/2 of 130 K, lower than that of 160 K observed with the related compound [Fe(bipy){H2B(pyz)2}2] (2), which contains a conventional bipy ligand. A computational study of 1 and 2 reveals that the curvature of the nanohoop leads to the different SCO properties, suggesting that the SCO behaviour of iron(II) can be tuned by varying the size and diameter of the nanohoop.

15 Oct 10:08

[ASAP] A Neutral Heteroatomic Zintl Cluster for the Catalytic Hydrogenation of Cyclic Alkenes

by Oliver P. E. Townrow, Cheuk Chung, Stuart A. Macgregor, Andrew S. Weller, and Jose M. Goicoechea

TOC Graphic

Journal of the American Chemical Society
DOI: 10.1021/jacs.0c09742
22 Apr 13:16

[ASAP] Versatile Coordination Chemistry of Hexa-tert-butyl-octaphosphine

by Toni Grell and Evamarie Hey-Hawkins*

TOC Graphic

Inorganic Chemistry
DOI: 10.1021/acs.inorgchem.0c00262
31 Mar 15:27

Phosphacycloalkyldiones: synthesis and coordinative behaviour of 6- and 7-member cyclic diketophosphanyls

Dalton Trans., 2020, 49,5482-5492
DOI: 10.1039/D0DT00864H, Paper
Kyle G. Pearce, Vladimir Simenok, Ian R. Crossley
Condensation of glutaryl and adipoyl chlorides with bis(silyl)phosphanes RP(SiMe3)2 (R = Me, nBu, tBu, Ph, Mes) affords the conformationally fluxional phosphacycloalkyldiones (CH2)n(CO)2PR (n = 3, 4); their coordination behaviour is explored.
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13 Nov 11:27

Isolation of a Perfectly Linear Uranium(II) Metallocene

by Richard Layfield, Fu-Sheng Guo, Nikolaus Tsoureas, Guo-Zhang Huang, Ming-Liang Tong, Akseli Mansikkamäki
Angewandte Chemie International Edition Isolation of a Perfectly Linear Uranium(II) Metallocene

A new generation: Reduction of the uranium(III) metallocene [(η5‐C5 i Pr5)2UI] with potassium graphite produces the “second‐generation” uranocene [(η5‐C5 i Pr5)2U], which contains uranium in the formal divalent oxidation state. The geometry of [(η5‐C5 i Pr5)2U] is that of a perfectly linear bis(cyclopentadienyl) sandwich complex.


Abstract

Reduction of the uranium(III) metallocene [(η5‐C5 i Pr5)2UI] (1) with potassium graphite produces the “second‐generation” uranocene [(η5‐C5 i Pr5)2U] (2), which contains uranium in the formal divalent oxidation state. The geometry of 2 is that of a perfectly linear bis(cyclopentadienyl) sandwich complex, with the ground‐state valence electron configuration of uranium(II) revealed by electronic spectroscopy and density functional theory to be 5f3 6d1. Appreciable covalent contributions to the metal‐ligand bonds were determined from a computational study of 2, including participation from the uranium 5f and 6d orbitals. Whereas three unpaired electrons in 2 occupy orbitals with essentially pure 5f character, the fourth electron resides in an orbital defined by strong 7s‐6d mixing.